How to take ampicillin?


Ampicillin Side Effects

Medically reviewed by Last updated on Sep 3, 2018.

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In Summary

Commonly reported side effects of ampicillin include: eosinophilia and skin rash. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to ampicillin: oral capsules, oral for suspension, parenteral powder for injection or infusion

Side effects include:

GI effects (diarrhea, nausea), rash.

For Healthcare Professionals

Applies to ampicillin: compounding powder, injectable powder for injection, oral capsule, oral powder for reconstitution


Very common (10% or more): Rash, pruritus, exanthema, itching

Common (1% to 10%): Morbilliform rash

Uncommon (0.1% to 1%): Angioneurotic edema, allergic vasculitis, exfoliative dermatitis, exudative erythema multiforme, urticaria, Stevens-Johnson syndrome, toxic epidermal necrolysis

Frequency not reported: Erythematous maculopapular rash (including mildly pruritic), macular rash, purpura, maculopapular rash, skin reactions (e.g., erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis), other skin rashes, erythematous eruptions, acute generalized exanthematous pustulosis


Glossitis, stomatitis, black hairy tongue, nausea, vomiting, enterocolitis, pseudomembranous colitis, and diarrhea were typically associated with oral formulations.

Acute pancreatitis has been reported and confirmed by rechallenge with this drug in a patient in whom there was no other obvious cause of pancreatitis.

Very common (10% or more): Diarrhea, nausea, vomiting, flatulence/meteorism, soft stools, abdominal pain

Uncommon (0.1% to 1%): Glossitis, stomatitis, enterocolitis, pseudomembranous colitis

Frequency not reported: Oral candidiasis/moniliasis, black hairy tongue, Clostridium difficile-associated diarrhea, hemorrhagic colitis, sore mouth/tongue, pancreatitis, gastritis, generalized abdominal cramps


Common (1% to 10%): Localized phlebitis

Frequency not reported: Phlebitis at IV administration site, pain at IM administration site


Common (1% to 10%): Swelling and pain, exanthema and enanthem in the oral region

Uncommon (0.1% to 1%): Infection with fungi/resistant bacteria (especially during prolonged and/or repeated use), drug fever

Frequency not reported: Fever (including high fever)


Uncommon (0.1% to 1%): Serious allergic reactions (e.g., serum sickness, allergic nephritis)

Rare (0.01% to 0.1%): Life-threatening anaphylactic shock

Frequency not reported: Anaphylaxis, serum sickness-like reactions, hypersensitivity reactions (including urticarial rash, erythema multiforme, exfoliative dermatitis, edema, hypotension, fever, eosinophilia, dyspnea, interstitial nephritis, Henoch-Schonlein purpura, focal glomerulonephritis, Stevens-Johnson syndrome, bullous pemphigoid, hypersensitivity myocarditis, toxic epidermal necrolysis, fixed drug eruptions)


Very rare (less than 0.01%): Granulocytopenia, pancytopenia, prolonged bleeding time, prolonged prothrombin time

Frequency not reported: Prolonged activated partial thromboplastin time, platelet aggregation abnormalities, neutropenia, Henoch Schonlein purpura, red cell aplasia

Anemia, thrombocytopenia, hemolytic anemia, thrombocytopenic purpura, eosinophilia, leukopenia, and agranulocytosis have been reported during treatment with penicillins. In general, these reactions were reversible after stopping therapy and were believed to be sensitivity reactions.

Neutropenia was described in a case report of 3 pediatric patients who received high doses (150 to 400 mg/kg) of this drug IV. In all 3 cases, white blood cell and neutrophil counts returned to normal after discontinuation of therapy.

Nervous system

Seizures have been reported with renal dysfunction or at very high IV doses.

Seizures have been reported in patients with high serum drug levels, although these patients were otherwise very ill. High cerebral spinal fluid (CSF) levels of some penicillins were known to be potentially neurotoxic, and the CSF level of this drug increased significantly in meningitis.

Generalized seizures have been described in 2 patients during use of this drug, although in both cases, there were underlying disease factors that may have predisposed the patients to seizure activity.

Encephalopathy has occurred when blood drug level reached 800 mg/L.

Toxic symptoms (e.g., drowsiness, hyperreflexia, myoclonic twitches, convulsions, coma) have occurred at lower drug levels in patients with meningitis; the blood-brain barrier became more permeable in meningitis.

Rare (0.01% to 0.1%): Headache, dizziness, myoclonus, seizures

Frequency not reported: Encephalopathy, drowsiness, hyperreflexia, myoclonic twitches, convulsions, coma


Uncommon (0.1% to 1%): Acute interstitial nephritis

Very rare (less than 0.01%): Acute renal failure with excretion of urine crystals

Frequency not reported: Interstitial nephritis, nephropathy, glomerulonephritis


Uncommon (0.1% to 1%): Transaminase elevation

Frequency not reported: Hepatitis, cholestatic jaundice, elevated AST, moderately increased transaminases (transient), elevated ALT, cholestasis

Mild, temporary elevation in AST reported in patients who received larger (2 to 4 times) and more frequent IM injections than usual. Evidence indicated AST was released at IM injection sites for this drug and increased AST did not necessarily indicate liver involvement.


Crystalluria has been reported with high-dose IV administration.

Uncommon (0.1% to 1%): Crystalluria

Frequency not reported: Vaginal candidiasis/moniliasis


Uncommon (0.1% to 1%): Laryngeal edema

Frequency not reported: Laryngeal stridor


Frequency not reported: Arthralgia


Frequency not reported: Anorexia

1. Poe RH, Condemi JJ, Weinstein SS, Schuster RJ “Adult respiratory distress syndrome related to ampicillin sensitivity.” Chest 3 (1980): 449-51

2. “Product Information. Polycillin (ampicillin).” Apothecon Inc, Plainsboro, NJ.

4. Dolovich J, Ruhno J, Sauder DN, Ahlstedt S, Hargreave FE “Isolated late cutaneous skin test response to ampicillin: a distinct entity.” J Allergy Clin Immunol 82 (1988): 676-9

5. Chan HL “Fixed drug eruption to bacampicillin (ampicillin).” Arch Dermatol 120 (1984): 542

6. Cobbs CG, Livingston W “Shigella sonnei gastroenteritis after oral ampicillin therapy for an unrelated disorder.” South Med J 73 (1980): 1545-6

7. Midtvedt T, Carlstedt-Duke B, Hoverstad T, et al “Influence of peroral antibiotics upon the biotransformatory activity of the intestinal microflora in healthy subjects.” Eur J Clin Invest 16 (1986): 11-7

8. Guay DR, Craft JC “Comparative safety and efficacy of clarithromycin and ampicillin in the treatment of out-patients with acute bacterial exacerbation of chronic bronchitis.” J Intern Med 231 (1992): 295-301

9. Brause BD, Romankiewicz JA, Gotz V, Franklin JE Jr, Roberts RB “Comparative study of diarrhea associated with clindamycin and ampicillin therapy.” Am J Gastroenterol 73 (1980): 244-8

10. Craig WA, Gerber AU “Worldwide experience with bacampicillin administered twice a day.” Rev Infect Dis 3 (1981): 171-7

12. Hanline MH “Acute pancreatitis caused by ampicillin.” South Med J 80 (1987): 1069

13. Johnson JR, Lyons MF, Pearce W, et al “Therapy for women hospitalized with acute pyelonephritis: a randomized trial of ampicillin versus trimethoprim-sulfamethoxasole for 14 days.” J Infect Dis 163 (1991): 325-30

14. Konstantinidis AB, Markopoulos A, Trigonides G “Ampicillin induced erythema multiforme.” J Oral Med 40 (1985): 168-70

16. Beeching NJ, Gruer LD, Findlay CD, Geddes AM “A case of Henoch-Schonlein purpura syndrome following oral ampicillin.” J Antimicrob Chemother 10 (1982): 479-82

17. Castro SM, Schwartz RH, Nazarian LF “Ampicillin and amoxicillin delayed hypersensitivity: Side-chain-specific allergic reactions in a child.” Pediatr Asthma Allerg Immun 10 (1996): 197-203

18. Adcock BB, Rodman DP “Ampicillin-specific rashes.” Arch Fam Med 5 (1996): 301-4

20. Guinta JL, Fiumara N “Ampicillin allergy presenting as secondary syphilis.” Oral Surg Oral Med Oral Patho 2 (1984): 152-4

21. Marra CA, Shalansky KF “Ampicillin-induced macropapular versus urticarial rash.” Ann Pharmacother 30 (1996): 401-2

22. Chikwava KR, Savell VH Jr, Boyd TK “Fatal cephalosporin-induced acute hypersensitivity myocarditis.” Pediatr Cardiol 27 (2006): 777-80

23. Tagami H, Tatsuta K, Iwatski K, Yamada M “Delayed hypersensitivity in ampicillin-induced toxic epidermal necrolysis.” Arch Dermatol 119 (1983): 910-3

24. Heim K, Alge A, Marth C “Anaphylactic reaction to ampicillin and severe complication in the fetus.” Lancet 337 (1991): 859-60

25. Garty BZ, Offer I, Livni E, Danon YL “Erythema multiforme and hypersensitivity myocarditis caused by ampicillin.” Ann Pharmacother 28 (1994): 730-1

26. Hughes GS “Ampicillin and hematologic effects.” Ann Intern Med 99 (1983): 573

27. Berliner S, Sidi Y, Shaklai M, Pinkhas J “Appearance of thrombocytopenia and benign monoclonal gammopathy following intake of drugs.” Acta Haematol 67 (1982): 71-2

28. Singh N, Yu VL, Mieles LA, Wagener MM “Beta-lactam antibiotic-induced leukopenia in severe hepatic dysfunction: risk factors and implications for dosing in patients with liver disease.” Am J Med 94 (1993): 251-6

29. Hodgman T, Dasta JF, Armstrong DK, Visconti JA, Reilley TE “Ampicillin-associated seizures.” South Med J 77 (1984): 1323-5

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer

More about ampicillin

  • During Pregnancy or Breastfeeding
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  • Drug class: aminopenicillins

Consumer resources

  • Ampicillin
  • Ampicillin injection
  • Ampicillin Capsules
  • Ampicillin Injection Solution
  • Ampicillin Oral Suspension

Other brands: Principen, Omnipen-N, Totacillin-N

Professional resources

  • Ampicillin Trihydrate (AHFS Monograph)
  • … +5 more

Related treatment guides

  • Bacterial Infection
  • Bacterial Endocarditis Prevention
  • Bacteremia
  • Bronchitis
  • … +19 more

Ampicillin for infection

This leaflet is about the use of ampicillin for bacterial infection in children.

This leaflet has been written for parents and carers about how to use this medicine in children. Our information sometimes differs from that provided by the manufacturers, because their information is usually aimed at adult patients. Please read this leaflet carefully. Keep it somewhere safe so that you can read it again.

Name of drug

Brand name: Penbritin®, Rimacillin®

There is also a form of ampicillin with another medicine flucloxacillin, this is called co-fluampicil. Co-fluampicil is used for infections that are severe or caused by certain types of bacteria. Brands include Flu-Amp®.

Why is it important for my child to take this medicine?

It is important that your child takes this medicine in the way that your doctor has told you to so that it kills the harmful bacteria and gets rid of the infection.

What is ampicillin available as?

  • Capsules: 250 mg, 500 mg
  • Liquid medicine (suspension): 125 mg or 250 mg in 5 mL; may contain a small amount of sugar

When should I give ampicillin?

Ampicillin is usually given four times a day. This is usually first thing in the morning, at lunchtime, late afternoon and at bedtime. Ideally, these times are at least 4 hours apart (e.g. 8 am, midday, 4 pm, 8pm).

Give the medicine at about the same times each day so that this becomes part of your child’s daily routine, which will help you to remember.

How much should I give?

Your doctor will work out the amount of ampicillin (the dose) that is right for your child. The dose will be shown on the medicine label.

It is important that you follow your doctor’s instructions about how much to give.

How should I give it?

This medicine works best when the stomach is empty, so try to give it to your child ½ – 1 hour before they eat. It is OK for your child to have a glass of water, milk or juice after taking ampicillin.

Capsules should be swallowed whole with a glass of water, squash or milk (but not juice). Your child should not chew the capsule.

Liquid medicine: Shake the medicine well. Measure out the right amount using a medicine spoon or oral syringe. You can get these from your pharmacist. Do not use a kitchen teaspoon as it will not give the right amount.

When should the medicine start working?

The medicine will start working straight away and your child should start to get better after taking the medicine for 2 days. It is important that they take the whole course of medicine that has been prescribed. Do not stop early.

What if my child is sick (vomits)?

  • If your child is sick less than 30 minutes after having a dose of ampicillin, give them the same dose again.
  • If your child is sick more than 30 minutes after having a dose of ampicillin, you do not need to give them another dose. Wait until the next normal dose.

If your child is sick again, seek advice from your GP, pharmacist or hospital. They will decide what to do based on your child’s condition and the specific medicine involved.

What if I forget to give it?

Do not give the missed dose. Just give the next dose as usual.

What if I give too much?

Ampicillin is generally a safe drug, and is unlikely to cause harm if your child has an extra dose by mistake.

If you worried you may have given your child too much, contact your doctor or local NHS services (111 in England and Scotland, 0845 4647 in Wales). Have the medicine packet with you if you telephone for advice.

Are there any possible side-effects?

We use medicines to make our children better, but sometimes they have other effects that we don’t want (side-effects).

Side-effects that you must do something about

If your child is short of breath or wheezing, or their face, lips or tongue start to swell, or they develop a rash, they may be allergic to ampicillin. Take your child to hospital or call an ambulance straight away.

If your child gets a lumpy red rash, they may have another infection such as glandular fever. Take them to your doctor.

Other side-effects you need to know about
  • Your child may get some stomach pains, diarrhoea (runny poo), vomiting or feel sick when they first start taking ampicillin. These side-effects are usually mild and improve with time. Giving the medicine just before some food may help. The section ‘Important things to know about taking antibiotics’ below contains advice on what to do about diarrhoea.
  • If your child has diarrhoea that lasts for longer than 4 days, or it has blood in it, contact your doctor.
  • You may see white patches inside your child’s mouth and throat, and girls may get itching or soreness around the vagina. This is caused by a fungal infection called thrush. If you think your child may have thrush, contact your doctor or pharmacist for advice.

There may, sometimes, be other side-effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor. You can report any suspected side-effects to a UK safety scheme at

Important things to know about taking antibiotics

  • It is important that your child completes the course of antibiotic. This means that they must take the medicine for the number of days that the doctor has told you to, or until all of the medicine has been taken. If you stop giving the antibiotic too soon, the bacteria that are left will start to multiply again, and may cause another infection. There is also a risk that these bacteria will be ‘resistant’ to the first antibiotic. This means that it might not work next time, and your child might need a different antibiotic, which might not work as well or cause more side-effects.
  • Children are sometimes sick (vomit) or get diarrhoea when taking antibiotics. Encourage them to drink water to replace the fluid they have lost.
  • Do not give your child any medicine to stop the diarrhoea unless your doctor has told you to.
  • Try to give the medicine at about the same times each day, to help you remember, and to make sure that there is the right amount of medicine in your child’s body to kill the bacteria.
  • Only give this medicine to your child for their current infection.
  • Never save medicine for future illnesses. Give old or unused antibiotics to your pharmacist to dispose of.
  • Only give the antibiotic to the child for whom it was prescribed. Never give it to anyone else, even if their condition appears to be the same, as this could do harm.

If you think someone else may have taken the medicine by accident, contact your doctor for advice.

  • Antibiotics only kill bacteria; they do not kill viruses. This means that they do not work against colds, sore throats, flu or other infections that are caused by viruses. Your doctor will not prescribe antibiotics for these illnesses.

Can other medicines be given at the same time as ampicillin?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.
  • Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal or complementary medicines.

Is there anything else I need to know about ampicillin?

  • Your child should not have ampicillin if they are allergic to penicillin antibiotics.
  • If your child has ever had an allergic reaction or other reaction to any medicine, tell your doctor. If you have forgotten to tell your doctor, check with the doctor or pharmacist before giving ampicillin to your child.

Where should I keep this medicine?

  • Keep the medicine in a cupboard, away from heat and direct sunlight. It does not need to be kept in the fridge.
  • Make sure that children cannot see or reach it.
  • Keep the medicine in the container it came in.

Who to contact for more information

Your child’s doctor, pharmacist or nurse will be able to give you more information about ampicillin and about other medicines used to treat bacterial infections.

Ampicillin (injection)

Generic Name: ampicillin (injection) (AMP i sil in)
Brand Name: Omnipen-N, Totacillin-N

Medically reviewed by on Apr 15, 2019 – Written by Cerner Multum

  • Overview
  • Side Effects
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  • Professional
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What is ampicillin injection?

Ampicillin is a penicillin antibiotic that fights bacteria.

Ampicillin injection is used to treat or prevent many different types of infections such as bladder infections, pneumonia, meningitis, gonorrhea, and infections of the stomach, intestines, heart, or blood.

Ampicillin may also be used for purposes not listed in this medication guide.

Important Information

You should not use ampicillin if you are allergic to any penicillin antibiotic.

Before taking this medicine

You should not use this medicine if you are allergic to ampicillin or to any other penicillin antibiotic, such as amoxicillin (Amoxil, Augmentin, Moxatag, and others), carbenicillin, dicloxacillin, or penicillin.

To make sure ampicillin is safe for you, tell your doctor if you have:

  • allergies to any foods or drugs;

  • an allergy to a cephalosporin antibiotic, such as cefdinir (Omnicef), cefprozil (Cefzil), cefuroxime (Ceftin), cephalexin (Keflex), and others; or

  • if you also take a medicine called allopurinol.

This medicine is not expected to harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Ampicillin can make birth control pills less effective. Ask your doctor about using non hormonal birth control (condom, diaphragm with spermicide) to prevent pregnancy.

Ampicillin can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

How is ampicillin injection given?

Ampicillin is injected into a muscle, or into a vein through an IV. You may be shown how to use an IV at home. Do not self-inject ampicillin if you do not understand how to give the injection and properly dispose of used needles, IV tubing, and other items used to inject the medicine.

You may need to mix ampicillin with a liquid (diluent) before using it. If you are using the injections at home, be sure you understand how to properly mix and store the medicine. You should use the injection as soon as possible after mixing it.

Use a disposable needle and syringe only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof “sharps” disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.

If you are being treated for gonorrhea, your doctor may also have you tested for syphilis, another sexually transmitted disease.

Your doctor may switch you from ampicillin injection to an oral form of this medicine. Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Ampicillin will not treat a viral infection such as the flu or a common cold.

If you use this medicine long-term, you may need frequent medical tests.

Ampicillin can cause unusual results with certain lab tests for glucose (sugar) in the urine. Tell any doctor who treats you that you are using this medicine.

Store unmixed ampicillin at room temperature away from moisture and heat.

After mixing your medicine, you will need to use it within a certain number of hours. This will depend on the diluent used, and whether the mixture is stored at room temperature or in a refrigerator. Carefully follow the mixing and storage instructions provided with your medicine. Ask your pharmacist if you have questions.

What happens if I miss a dose?

Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while receiving ampicillin injection?

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Ampicillin injection side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • severe stomach pain, diarrhea that is watery or bloody;

  • fever, swollen glands, skin rash, joint pain, general ill feeling; or

  • pale skin, easy bruising or bleeding, unusual weakness.

Common side effects may include:

  • nausea, vomiting, stomach pain;

  • itching or rash;

  • swollen, black, or “hairy” tongue; or

  • vaginal itching or discharge.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect ampicillin injection?

Other drugs may interact with ampicillin, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2018 Cerner Multum, Inc. Version: 1.01.

Medical Disclaimer

  • Side Effects
  • During Pregnancy or Breastfeeding
  • Dosage Information
  • Drug Images
  • Drug Interactions
  • Compare Alternatives
  • Support Group
  • Pricing & Coupons
  • 3 Reviews
  • Drug class: aminopenicillins
  • Ampicillin
  • Ampicillin Capsules
  • Ampicillin Injection Solution
  • Ampicillin Oral Suspension

Other brands: Principen, Omnipen-N, Totacillin-N

  • Ampicillin Trihydrate (AHFS Monograph)
  • … +5 more
  • Bacterial Infection
  • Bacterial Endocarditis Prevention
  • Bacteremia
  • Bronchitis
  • … +19 more

About ampicillin

Type of medicine A penicillin antibiotic
Used for Infections (in adults and children)
Also called Penbritin®;
In combination with flucloxacillin: co-fluampicil
Available as Capsules, oral liquid medicine and injection

Ampicillin is given to treat a bacterial infection. It is mainly prescribed for sinus and chest infections, urine infections, and ear infections. It is a penicillin antibiotic which treats infection by killing the germs (bacteria) responsible for the infection.

Ampicillin is also available in combination with another penicillin antibiotic called flucloxacillin. The combination is called co-fluampicil.

Before taking ampicillin

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking ampicillin it is important that your doctor knows:

  • If you suspect you may have glandular fever (the symptoms are high temperature (fever), sore throat, swollen glands).
  • If you have an allergic condition, or if you have ever had an allergic reaction to a medicine. This is especially important if you have ever had a bad reaction to any penicillin antibiotic.
  • If you have any problems with the way your kidneys work.
  • If you are pregnant or breastfeeding. Ampicillin is not known to be harmful to babies; however, it is still important that you tell your doctor if you are expecting or breastfeeding a baby.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

How to take ampicillin

  • Before you start the treatment, read the manufacturer’s printed information leaflet from inside the pack. It will give you more information about ampicillin and will provide you with a full list of the side-effects which you may experience from taking it.
  • Take ampicillin exactly as your doctor tells you to. It is usually taken four times a day, every six hours. Your doctor or pharmacist will tell you how you should take the medication, and this information will be printed on the label of the pack to remind you. It is important that you space out the doses evenly during the day. Swallow the capsules with a drink of water.
  • You should take ampicillin when your stomach is empty, which means taking your doses one hour before you eat any food, or waiting until two hours afterwards. This is because your body absorbs less ampicillin after a meal, which means the medicine is less effective.
  • If you have been given liquid medicine for a child, read the directions carefully to make sure you measure out the correct amount of medicine.
  • If you forget to take a dose, take one as soon as you remember. Try to take the correct number of doses each day, but do not take two doses at the same time to make up for a forgotten dose.

Getting the most from your treatment

  • Even if you feel your infection has cleared up, keep taking the antibiotic until the course is finished (unless a doctor tells you to stop). This is to prevent the infection from coming back.
  • Antibiotics are prescribed in short courses of treatment. Your doctor will tell you how long your course of treatment will last – this is not usually for longer than 14 days. If you still feel unwell after finishing the course, go back to see your doctor.
  • Some people develop redness and itching in the mouth or vagina (thrush) after taking a course of antibiotics. If this happens to you, speak with your doctor or pharmacist for advice.
  • If you are taking the contraceptive ‘pill’ at the same time as this antibiotic, the effectiveness of the ‘pill’ can be reduced if you have a bout of being sick (vomiting) or diarrhoea which lasts for more than 24 hours. If this should happen, ask your doctor or pharmacist for advice about what additional contraceptive precautions to use over the next few days. There is no need to use additional precautions for any bouts of sickness or diarrhoea which last for less than 24 hours.
  • Ampicillin can stop the oral typhoid vaccine from working. If you are due to have any vaccinations, make sure the person treating you knows that you are taking this antibiotic.

Can ampicillin cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with ampicillin. You will find a full list in the manufacturer’s information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common ampicillin side-effects (these affect less than 1 in 10 people) What can I do if I experience this?
Feeling sick (nausea) or being sick (vomiting) Stick to simple foods
Diarrhoea Drink plenty of water to replace any lost fluids. If the diarrhoea continues, becomes severe, or contains blood, let your doctor know straightaway
Redness and itching in the mouth or vagina (thrush) Speak with a pharmacist or your doctor for advice about treatment
Skin rash Let your doctor know as soon as possible as your treatment will need to be changed

Important: if you develop an itchy rash, swollen face or mouth, or have difficulty breathing, these may be signs that you are allergic to a penicillin antibiotic. Do not take any more ampicillin and speak with your doctor or go to your local accident and emergency department straightaway.

If you experience any other symptoms which you think may be due to the antibiotic, speak with your doctor or pharmacist for further advice.

How to store ampicillin

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • If you have been given liquid medicine, store it in a refrigerator. It will have been made up by the pharmacy and lasts for seven days, so check the expiry date on the bottle and do not use it after this date.

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you buy any medicines, check with a pharmacist that they are safe to take with your other medicines.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Updated 3/2019

How long it takes for a medication to leave your body depends on its dose, and its metabolism. But you may be asking how long it takes for the medication’s effects to go away. That can take longer, sometimes much longer. Antidepressants are among the trickiest ones. Here is the simple part: medications disappear from your body more quickly at first, and then more slowly when there is less of it around for the body to find and remove.

The concept of half-life: simple

The result is a relatively smooth curve (of declining amounts in the blood) that falls steeply at first and very slowly at the very end. We measure the disappearance of a meditation from the bloodstream using a concept of “half-life”: the amount of time it takes for the amount of medication in your bloodstream to fall by half. This may sound complex but it’s actually pretty simple.

It turns out that the rate of decrease is consistent, in a funny way. The amount of time it takes for the concentration (the amount of medication in a given amount of blood) to decrease by one half stays the same, even though the rate of decrease is fast at first and slow later, as shown in the graph.

Medication leaving the body

Here’s how that works. Imagine that you have a medication in your body that starts out with 100 units in every drop of blood. When you stop taking it, your body continues to metabolize it, so the concentration is going to decrease. Let’s say this is a medication that disappears quickly, like methylphenidate/Ritalin: in about three hours, half of it is gone. So at three hours after the last dose, you have 50 units in every drop of blood. Now, because the liver will have a harder time finding those 50 units to remove (compared to when there were 100 units in every drop), the rate of disappearance slows down. In three more hours (six hours from the last dose), you’ll be down to 25 units. Three hours later, you’ll be down to 12.5 units. Three hours later, 7.25 units; then 3.125 units, and so forth. As you can see, the numbers very slowly approach zero.

So, when has all the medication left your body? There is no obvious “zero”, because the very end of this process takes a long time.

Using half-life in medicine

Instead, in medicine we make an assumption. It’s not perfectly accurate but close enough. We say the medication is pretty much gone after “4 to 5 half lives”. If the medication has a half-life of 3 hours, then it will be close to gone in 12 to 15 hours after the last dose. But notice that half was gone in 3 hours, and by 6 hours you were down to a quarter of the original highest amount. The medication effects could be gone even though some medication is still in your blood.

Most medications have a half-life of about 24 hours, so they are gone — or close to it — in 4-5 days. A few medications have very long half-lives. Fluoxetine/Prozac, for example, takes almost a week to decrease by half, so even when it is no longer being swallowed, it takes slightly over a month for it to be completely gone.

But when is the medication effect gone?

I’m guessing the question you are really asking is how long does it take the effects of your medication to go away. Of course the changes in the brain chemistry that medications create do not immediately reverse themselves. It takes many more days — perhaps weeks, or even months — for the brain chemistry to go back to the way it was before the medication was started. So even though the medication goes away fairly quickly, the effects can last much longer than that. Sometimes people can stay well for months before relapsing. By then, it’s not so clear if stopping the medication was really the culprit.

How long for antidepressant effects to go away?

My area of interest, as you’ll see throughout this website, is the spectrum of mood disorders, from plain depression to “bipolar”. Antidepressants can do really weird things in some people, even those in the middle of the mood spectrum who don’t look “bipolar”. They can cause agitation, irritability, insomnia, and more.

Ironically, antidepressants can have these weird effects when they are started, or months after they’ve started — but also when they are stopped. And unfortunately, for some people the effects of stopping an antidepressant can last for weeks, or months. This is not a half-life issue, it’s a brain effects issue. If that’s why you landed here, I’m sorry; and I’d urge you to learn more on my antidepressant withdrawal page.

A reminder

In any case , you should not stop any medication without talking about it with your doctor or nurse practitioner. She or he can help you plan for what comes next. For many medications, especially if they are stopped suddenly, some very bad things can happen when they are stopped without some kind of supervision and backup plan. So make sure you DO NOT do this on your own.

Ampi 500 Uses


Did you have any side effects with this medicine? No Yes

  • Ampi 500 indications
  • Uses of Ampi 500 in details
  • Ampi 500 description
  • Ampi 500 dosage
  • Ampi 500 interactions
  • Ampi 500 side effects
  • Ampi 500 contraindications

What is Ampi 500?

Penicillins are used to treat infections caused by bacteria. They work by killing the bacteria or preventing their growth.

There are several different kinds of penicillins. Each is used to treat different kinds of infections. One kind of penicillin usually may not be used in place of another. In addition, penicillins are used to treat bacterial infections in many different parts of the body. They are sometimes given with other antibacterial medicines (antibiotics). Some of the penicillins may also be used for other problems as determined by your doctor. However, none of the penicillins will work for colds, flu, or other virus infections.

Penicillins are available only with your doctor’s prescription.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, penicillins are used in certain patients with the following medical conditions:

  • Chlamydia infections in pregnant women—Amoxicillin and Ampi 500
  • Gas gangrene—Penicillin G
  • Helicobacter pylori-associated gastritis or peptic ulcer disease—Amoxicillin
  • Leptospirosis—Ampi 500 and penicillin G
  • Lyme disease—Amoxicillin and penicillin V
  • Typhoid fever—Amoxicillin and Ampi 500

Ampi 500 indications

An indication is a term used for the list of condition or symptom or illness for which the medicine is prescribed or used by the patient. For example, acetaminophen or paracetamol is used for fever by the patient, or the doctor prescribes it for a headache or body pains. Now fever, headache and body pains are the indications of paracetamol. A patient should be aware of the indications of medications used for common conditions because they can be taken over the counter in the pharmacy meaning without prescription by the Physician. sponsored

Ampi 500 for Injection, USP is indicated in the treatment of infections caused by susceptible strains of the designated organisms in the following conditions:

Respiratory Tract Infections caused by S. pneumoniae (formerly D. pneumoniae), Staphylococcus aureus (penicillinase and nonpenicillinase-producing), H. influenzae, and Group A beta-hemolytic streptococci.

Bacterial Meningitis caused by E. coli, Group B Streptococci, and other Gram-negative bacteria (Listeria monocytogenes, N. meningitidis). The addition of an aminoglycoside with Ampi 500 may increase its effectiveness against Gram-negative bacteria.

Septicemia and Endocarditis caused by susceptible Gram-positive organisms including Streptococcus sp., penicillin G-susceptible staphylococci, and enterococci. Gram-negative sepsis caused by E. coli, Proteus mirabilis and Salmonella sp. respond to Ampi 500. Endocarditis due to enterococcal strains usually respond to intravenous therapy. The addition of an aminoglycoside may enhance the effectiveness of Ampi 500 when treating streptococcal endocarditis.

Urinary Tract Infections caused by sensitive strains of E. coli and Proteus mirabilis.

Gastrointestinal Infections caused by Salmonella typhosa (typhoid fever), other Salmonella sp., and Shigella sp. (dysentery) usually respond to oral or intravenous therapy.

Bacteriology studies to determine the causative organisms and their susceptibility to Ampi 500 should be performed. Therapy may be instituted prior to obtaining results of susceptibility testing.

It is advisable to reserve the parenteral form of this drug for moderately severe and severe infections and for patients who are unable to take the oral forms. A change to oral Ampi 500 may be made as soon as appropriate.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of Ampi 500 for Injection, USP and other antibacterial drugs, Ampi 500 for Injection, USP should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

Indicated surgical procedures should be performed.

How should I use Ampi 500?

Use Ampi 500 solution as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Ampi 500 solution is usually given as an injection at your doctor’s office, hospital, or clinic. If you will be using Ampi 500 solution at home, a health care provider will teach you how to use it. Be sure you understand how to use Ampi 500 solution. Follow the procedures you are taught when you use a dose. Contact your health care provider if you have any questions.
  • Do not use Ampi 500 solution if it contains particles, is cloudy or discolored, or if the vial is cracked or damaged.
  • Use Ampi 500 solution on a regular schedule to get the most benefit from it. Using Ampi 500 solution at the same time each day will help you remember to use it.
  • If Ampi 500 solution is given intravenously (IV) or intramuscularly (IM), it should be given within 1 hour of mixture. After 1 hour, it begins to lose its potency.
  • To clear up your infection completely, use Ampi 500 solution for the full course of treatment. Keep using it even if you feel better in a few days.
  • Keep this product, as well as syringes and needles, out of the reach of children and pets. Do not reuse needles, syringes, or other materials. Ask your health care provider how to dispose of these materials after use. Follow all local rules for disposal.
  • If you miss a dose of Ampi 500 solution, use it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not use 2 doses at once.

Ask your health care provider any questions you may have about how to use Ampi 500 solution.

Uses of Ampi 500 in details

There are specific as well as general uses of a drug or medicine. A medicine can be used to prevent a disease, treat a disease over a period or cure a disease. It can also be used to treat the particular symptom of the disease. The drug use depends on the form the patient takes it. It may be more useful in injection form or sometimes in tablet form. The drug can be used for a single troubling symptom or a life-threatening condition. While some medications can be stopped after few days, some drugs need to be continued for prolonged period to get the benefit from it. sponsored

Ampi 500 is used to treat a wide variety of bacterial infections. It is a penicillin-type antibiotic. It works by stopping the growth of bacteria.

This antibiotic treats only bacterial infections. It will not work for viral infections (e.g., common cold, flu). Unnecessary use or overuse of any antibiotic can lead to its decreased effectiveness.

How to use Ampi 500

Take this medication by mouth usually 4 times a day (every 6 hours), or as directed by your doctor. Take Ampi 500 on an empty stomach (1 hour before or 2 hours after a meal) with a full glass of water. Drink plenty of fluids while using this medication unless your doctor tells you otherwise.

The dosage is based on your medical condition and response to therapy.

Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals.

Continue to take this medication until the full-prescribed amount is finished even if symptoms disappear after a few days. Stopping the medication too early may allow bacteria to continue to grow, which may result in a relapse of the infection.

Inform your doctor if your condition persists or worsens.

Ampi 500 description


A topical anti-infective agent effective against gram-negative and gram-positive bacteria. It is used for superficial wounds, burns, ulcers, and skin infections. Ampi 500 has also been administered orally in the treatment of trypanosomiasis.

Ampi 500 dosage

Adults and children weighing over 20 Kg: For genitourinary or gastrointestinal tract infections other than gonorrhea in men and women, the usual dose is 500 mg q.i.d. in equally spaced doses; severe or chronic infections may require larger doses. For the treatment of gonorrhea in both men and women, a single oral dose of 3.5 grams of Ampi 500 administered simultaneously with 1 gram of probenecid is recommended. Physicians are cautioned to use no less than the above recommended dosage for the treatment of gonorrhea. Follow-up cultures should be obtained from the original site(s) of infection 7 to 14 days after therapy. In women, it is also desirable to obtain culture test-of-cure from both the endocervical and anal canals. Prolonged intensive therapy is needed for complications such as prostatitis and epididymitis. For respiratory tract infections, the usual dose is 250 mg q.i.d. in equally spaced doses.

Pediatric Patients weighing 20 Kg or less: For genitourinary or gastrointestinal tract infections, the usual dose is 100 mg/kg/day total, q.i.d. in equally divided and spaced doses.

For respiratory tract infections, the usual dose is 50 mg/kg/day total, in equally divided and spaced doses three to four times daily. Doses for children should not exceed doses recommended for adults.

All patients, irrespective of age and weight: Larger doses may be required for severe or chronic infections. Although Ampi 500 is resistant to degradation by gastric acid, it should be administered at least one half-hour before or two hours after meals for maximal absorption. Except for the single dose regimen for gonorrhea referred to above, therapy should be continued for a minimum of 48 to 72 hours after the patient becomes asymptomatic or evidence that bacterial eradication has been obtained. In infections caused by hemolytic strains of streptococci, a minimum of 10 days’ treatment is recommended to guard against the risk of rheumatic fever or glomerulonephritis. In the treatment of chronic urinary or gastrointestinal infections, frequent bacteriologic and clinical appraisal is necessary during therapy and may be necessary for several months afterwards. Stubborn infections may require treatment for several weeks. Smaller doses than those indicated above should not be used.

Directions for mixing

Oral Suspension

Prepare suspension at time of dispensing. For ease of preparation, add water to the bottle in two portions and shake well after each addition.

125 mg/5 mL

Add a total of 86 mL to the 100 mL package and 170 mL to the 200 mL package. This will provide 100 mL and 200 mL of suspension, respectively. Each 5 mL (teaspoonful) will contain Ampi 500 trihydrate equivalent to 125 mg Ampi 500.

250 mg/5 mL

Add a total of 70 mL to the 100 mL package and 139 mL to the 200 mL package. This will provide 100 mL and 200 mL of suspension, respectively. Each 5 mL (teaspoonful) will contain Ampi 500 trihydrate equivalent to 250 mg Ampi 500.

Ampi 500 interactions

See also:
What other drugs will affect Ampi 500?


As penicillins like Ampi 500 only show activity against proliferating organisms, they should not be combined with bacteriostatic antibiotics. But if consistent with susceptibility tests, they may be combined with other bactericidal antibiotics (cephalosporins, aminoglycosides).

If applied concomitantly, probenecid leads to higher and sustained plasma levels by suppressing renal elimination. As a result, probenecid may reduce the distribution and diffusion of Ampi 500 in body tissues.

Patients simultaneously receiving allopurinol run a higher risk of developing rashes.

In rare cases Ampi 500, like other antibiotics, may reduce the effectiveness of oral contraceptives.

If IM injections are painful, Ampi 500 may be injected in a 0.5% procaine hydrochloride solution.

Ampi 500 may reduce the urinary excretion of atenolol.

Ampi 500 may interfere with urinary amino acid determinations by paper chromatography.

Incompatibilities: To prevent undesirable chemical reactions, no other drugs should be added to the solutions for injection or infusion. If unavoidable, other drugs (antibiotics) should be given before or after Ampi 500 dosing. Mixing with other solutions eg, whole blood, plasma, inverted sugars or dextrans, should be avoided.

Ampi 500 side effects

See also:
What are the possible side effects of Ampi 500?

As with other penicillins, it may be expected that untoward reactions will be essentially limited to sensitivity phenomena. They are more likely to occur in individuals who have previously demonstrated hypersensitivity to penicillins and in those with a history of allergy, asthma, hay fever, or urticaria.

The following adverse reactions have been reported as associated with the use of Ampi 500:

Glossitis, stomatitis, black “hairy” tongue, nausea, vomiting, enterocolitis, pseudomembranous colitis, and diarrhea. (These reactions are usually associated with oral dosage forms.)

Hypersensitivity Reactions

Skin rashes and urticaria have been reported frequently. A few cases of exfoliative dermatitis and erythema multiforme have been reported. Anaphylaxis is the most serious reaction experienced and has usually been associated with the parenteral dosage form.

Note: Urticaria, other skin rashes, and serum sickness-like reactions may be controlled with antihistamines and, if necessary, systemic corticosteroids. Whenever such reactions occur, Ampi 500 should be discontinued, unless, in the opinion of the physician, the condition being treated is life-threatening and amenable only to Ampi 500 therapy. Serious anaphylactic reactions require the immediate use of epinephrine, oxygen, and intravenous steroids.

Liver – A moderate rise in serum glutamic oxaloacetic transaminase (SGOT) has been noted, particularly in infants, but the significance of this finding is unknown. Mild transitory SGOT elevations have been observed in individuals receiving larger (two to four times) than usual and oft-repeated intramuscular injections. Evidence indicates that glutamic oxaloacetic transaminase (GOT) is released at the site of intramuscular injection of Ampi 500 sodium and that the presence of increased amounts of this enzyme in the blood does not necessarily indicate liver involvement.

Hemic and Lymphatic Systems – Anemia, thrombocytopenia, thrombocytopenic purpura, eosinophilia, leukopenia, and agranulocytosis have been reported during therapy with the penicillins. These reactions are usually reversible on discontinuation of therapy and are believed to be hypersensitivity phenomena.

Ampi 500 contraindications

See also:
What is the most important information I should know about Ampi 500?

Before using Ampi 500, tell your doctor if you are allergic to cephalosporins such as Ceclor, Ceftin, Duricef, Keflex, and others, or if you have asthma, kidney disease, a bleeding or blood clotting disorder, mononucleosis (also called “mono”), or a history of any type of allergy.

Ampi 500 can make birth control pills less effective, which may result in pregnancy. Before taking Ampi 500, tell your doctor if you use birth control pills.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Ampi 500 will not treat a viral infection such as the common cold or flu.

Do not share this medication with another person, even if they have the same symptoms you have.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, stop taking Ampi 500 and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Active ingredient matches for Ampi 500:



The results of a survey conducted on for Ampi 500 are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Ampi 500. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.

User reports

1 consumer reported useful

Was the Ampi 500 drug useful in terms of decreasing the symptom or the disease?
According to the reports released by website users, the below mentioned percentages of users say the drug is useful / not useful to them in decreasing their symptoms/disease. The usefulness of the drug depends on many factors, like severity of the disease, perception of symptom, or disease by the patient, brand name used , other associated conditions of the patient. If the drug is not effective or useful in your case, you need to meet the doctor to get re-evaluated about your symptoms/disease, and he will prescribe an alternative drug.

Users %
Useful 1 100.0%

Consumer reported price estimates

No survey data has been collected yet

2 consumers reported time for results

To what extent do I have to use Ampi 500 before I begin to see changes in my health conditions?
As part of the reports released by website users, it takes 1 day and a few days before you notice an improvement in your health conditions.
Please note, it doesn’t mean you will start to notice such health improvement in the same time frame as other users. There are many factors to consider, and we implore you to visit your doctor to know how long before you can see improvements in your health while taking Ampi 500. To get the time effectiveness of using Ampi 500 drug by other patients, please click here.

Users %
1 day 1 50.0%
5 days 1 50.0%

2 consumers reported age

Users %
30-45 1 50.0%
16-29 1 50.0%

Consumer reviews

There are no reviews yet. Be the first to write one!

Information checked by Dr. Sachin Kumar, MD Pharmacology

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