Side effects of terazosin

Terazosin

Generic Name: terazosin (ter AY zo sin)
Brand Names: Hytrin

Medically reviewed by Sanjai Sinha, MD Last updated on Apr 11, 2019.

  • Overview
  • Side Effects
  • Dosage
  • Professional
  • Interactions
  • More

What is terazosin?

Terazosin is in a group of drugs called alpha-adrenergic blockers. Terazosin relaxes your veins and arteries so that blood can more easily pass through them. It also relaxes the muscles in the prostate and bladder neck, making it easier to urinate.

Terazosin is used to treat hypertension (high blood pressure), or to improve urination in men with benign prostatic hyperplasia (enlarged prostate).

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

Important information

Terazosin may cause dizziness or fainting, especially when you first start taking it or when you start taking it again. You may wish to take this medication only at bedtime if it causes you to feel light-headed. Be careful if you drive or do anything that requires you to be alert. Avoid standing for long periods of time or becoming overheated during exercise and in hot weather. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

You should not use this medication if you are allergic to terazosin.

If you stop taking terazosin for any reason, call your doctor before you start taking it again. You may need a dose adjustment.

Terazosin can affect your pupils during cataract surgery. Tell your eye surgeon ahead of time that you are using terazosin. Do not stop using terazosin before surgery unless your surgeon tells you to.

Tell your doctor about all other medications you use, especially other blood pressure medications including diuretics (water pills).

Before taking this medicine

You should not use this medication if you are allergic to terazosin.

If you have a history of prostate cancer, you may need a dose adjustment or special tests to safely take terazosin.

Terazosin can affect your pupils during cataract surgery. Tell your eye surgeon ahead of time that you are using this medication. Do not stop using terazosin before surgery unless your surgeon tells you to.

FDA pregnancy category C. It is not known whether terazosin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication. It is not known whether terazosin passes into breast milk or if it could harm a nursing baby. Do not use terazosin without telling your doctor if you are breast-feeding a baby.

How should I take terazosin?

Take terazosin exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Your doctor may occasionally change your terazosin dose to make sure you get the best results.

Terazosin lowers blood pressure and may cause dizziness or fainting, especially when you first start taking it, or when you start taking it again. You may wish to take this medication only at bedtime if it causes you to feel light-headed. Call your doctor if you have severe dizziness or feel like you might pass out.

You may feel very dizzy when you first wake up. Be careful when standing or sitting up from a lying position.

If you stop taking terazosin for any reason, call your doctor before you start taking it again. You may need a dose adjustment.

Your blood pressure or prostate will need to be checked often. Visit your doctor regularly.

If you are being treated for high blood pressure, keep using terazosin even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.

Some things can cause your blood pressure to get too low. This includes vomiting, diarrhea, heavy sweating, heart disease, dialysis, a low-salt diet, or taking diuretics (water pills). Tell your doctor if you have a prolonged illness that causes diarrhea or vomiting.

Store terazosin at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

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

If you miss your doses for several days in a row, contact your doctor before restarting the medication. You may need a lower dose.

What happens if I overdose?

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

Overdose symptoms may include extreme dizziness or fainting.

What should I avoid?

Terazosin may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

To prevent dizziness, avoid standing for long periods of time or becoming overheated during exercise and in hot weather.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall. Drinking alcohol can increase certain side effects of terazosin.

Terazosin side effects

Get emergency medical help if you have any of these signs of an allergic reaction to terazosin: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:

  • fast or pounding heartbeats or fluttering in your chest;

  • feeling like you might pass out;

  • swelling in your hands, ankles, or feet; or

  • penis erection that is painful or lasts 4 hours or longer.

Less serious terazosin side effects may include:

  • mild dizziness;

  • weakness, drowsiness;

  • blurred vision;

  • nausea; or

  • headache.

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.

Terazosin dosing information

Usual Adult Dose for Hypertension:

Initial dose: 1 mg orally once a day at bedtime
Maintenance dose: 1-5 mg orally once a day.
Maximum dose: 20 mg per day.

Usual Adult Dose for Benign Prostatic Hyperplasia:

Initial dose: 1 mg orally once a day at bedtime.
Maintenance dose: Increased in a stepwise fashion to 2 mg, 5 mg, or 10 mg once a day to achieve desired improvement of symptoms.

What other drugs will affect terazosin?

Tell your doctor about all other medications you use, especially:

This list is not complete and other drugs may interact with terazosin. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Further information

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 1996-2020 Cerner Multum, Inc. Version: 8.01.

Medical Disclaimer

More about terazosin

  • Side Effects
  • During Pregnancy or Breastfeeding
  • Dosage Information
  • Drug Images
  • Drug Interactions
  • Support Group
  • Pricing & Coupons
  • En Español
  • 38 Reviews
  • Drug class: antiadrenergic agents, peripherally acting
  • FDA Alerts (1)

Consumer resources

  • Terazosin
  • Terazosin (Advanced Reading)

Other brands: Hytrin

Professional resources

  • Terazosin Hydrochloride (AHFS Monograph)
  • … +3 more

Related treatment guides

  • Benign Prostatic Hyperplasia
  • High Blood Pressure
  • Hyperhidrosis
  • Prepak Systems Inc.
  • Ranbaxy Laboratories
  • Rebel Distributors Corp.
  • Redpharm Drug
  • Remedy Repack
  • Resource Optimization and Innovation LLC
  • Sandoz
  • Southwood Pharmaceuticals
  • Teva Pharmaceutical Industries Ltd.
  • Torpharm Inc.
  • Tya Pharmaceuticals
  • UDL Laboratories
  • Va Cmop Dallas
  • Vangard Labs Inc.
  • Dosage forms

    Form Route Strength
    Capsule, liquid filled Oral 1 mg/1
    Capsule, liquid filled Oral 10 mg/1
    Capsule, liquid filled Oral 2 mg/1
    Capsule, liquid filled Oral 5 mg/1
    Tablet Oral 1 mg/1
    Tablet Oral 10 mg/1
    Tablet Oral 2 mg/1
    Tablet Oral 5 mg/1
    Kit; tablet Oral
    Tablet Oral 1 mg
    Tablet Oral 10 mg
    Tablet Oral 2 mg
    Tablet Oral 5 mg
    Capsule Oral 1 mg/1
    Capsule Oral 10 mg/1
    Capsule Oral 2 mg/1
    Capsule Oral 5 mg/1
    Tablet Oral

    Prices

    Unit description Cost Unit
    Hytrin 10 mg Tablet 1.85USD tablet
    Terazosin HCl 1 mg capsule 1.67USD capsule
    Terazosin HCl 10 mg capsule 1.67USD capsule
    Terazosin HCl 2 mg capsule 1.67USD capsule
    Terazosin HCl 5 mg capsule 1.67USD capsule
    Hytrin 5 mg Tablet 1.26USD tablet
    Hytrin 2 mg Tablet 0.93USD tablet
    Apo-Terazosin 10 mg Tablet 0.92USD tablet
    Novo-Terazosin 10 mg Tablet 0.92USD tablet
    Nu-Terazosin 10 mg Tablet 0.92USD tablet
    Pms-Terazosin 10 mg Tablet 0.92USD tablet
    Ratio-Terazosin 10 mg Tablet 0.92USD tablet
    Hytrin 1 mg Tablet 0.73USD tablet
    Apo-Terazosin 5 mg Tablet 0.63USD tablet
    Novo-Terazosin 5 mg Tablet 0.63USD tablet
    Nu-Terazosin 5 mg Tablet 0.63USD tablet
    Pms-Terazosin 5 mg Tablet 0.63USD tablet
    Ratio-Terazosin 5 mg Tablet 0.63USD tablet
    Apo-Terazosin 2 mg Tablet 0.46USD tablet
    Novo-Terazosin 2 mg Tablet 0.46USD tablet
    Nu-Terazosin 2 mg Tablet 0.46USD tablet
    Pms-Terazosin 2 mg Tablet 0.46USD tablet
    Ratio-Terazosin 2 mg Tablet 0.46USD tablet
    Apo-Terazosin 1 mg Tablet 0.37USD tablet
    Novo-Terazosin 1 mg Tablet 0.37USD tablet
    Nu-Terazosin 1 mg Tablet 0.37USD tablet
    Pms-Terazosin 1 mg Tablet 0.37USD tablet
    Ratio-Terazosin 1 mg Tablet 0.37USD tablet

    DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only. Patents

    Patent Number Pediatric Extension Approved Expires (estimated)
    Unlock Additional Data
    US5294615 No 1994-03-15 2013-04-29 US
    US5212176 No 1993-05-18 2010-06-29 US

    Additional Data Available

    • Filed On Filed On

      The date on which a patent was filed with the relevant government.

      Learn more

    Properties

    State Solid Experimental Properties

    Property Value Source
    melting point (°C) 271-274

    Predicted Properties

    Property Value Source
    Water Solubility 1.5 mg/mL ALOGPS
    logP 1.12 ALOGPS
    logP 1.18 ChemAxon
    logS -2.4 ALOGPS
    pKa (Strongest Acidic) 19.93 ChemAxon
    pKa (Strongest Basic) 7.24 ChemAxon
    Physiological Charge 1 ChemAxon
    Hydrogen Acceptor Count 8 ChemAxon
    Hydrogen Donor Count 1 ChemAxon
    Polar Surface Area 103.04 Å2 ChemAxon
    Rotatable Bond Count 4 ChemAxon
    Refractivity 105.18 m3·mol-1 ChemAxon
    Polarizability 41.26 Å3 ChemAxon
    Number of Rings 4 ChemAxon
    Bioavailability 1 ChemAxon
    Rule of Five Yes ChemAxon
    Ghose Filter Yes ChemAxon
    Veber’s Rule No ChemAxon
    MDDR-like Rule No ChemAxon

    Predicted ADMET features

    Property Value Probability
    Human Intestinal Absorption + 1.0
    Blood Brain Barrier + 0.9646
    Caco-2 permeable + 0.8868
    P-glycoprotein substrate Substrate 0.698
    P-glycoprotein inhibitor I Non-inhibitor 0.5666
    P-glycoprotein inhibitor II Non-inhibitor 0.8619
    Renal organic cation transporter Non-inhibitor 0.6319
    CYP450 2C9 substrate Non-substrate 0.8864
    CYP450 2D6 substrate Non-substrate 0.8032
    CYP450 3A4 substrate Substrate 0.7753
    CYP450 1A2 substrate Non-inhibitor 0.9046
    CYP450 2C9 inhibitor Non-inhibitor 0.9435
    CYP450 2D6 inhibitor Non-inhibitor 0.9628
    CYP450 2C19 inhibitor Non-inhibitor 0.9492
    CYP450 3A4 inhibitor Non-inhibitor 0.7905
    CYP450 inhibitory promiscuity Low CYP Inhibitory Promiscuity 0.901
    Ames test Non AMES toxic 0.5943
    Carcinogenicity Non-carcinogens 0.906
    Biodegradation Not ready biodegradable 0.9785
    Rat acute toxicity 2.2262 LD50, mol/kg Not applicable
    hERG inhibition (predictor I) Weak inhibitor 0.8368
    hERG inhibition (predictor II) Inhibitor 0.8204

    ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397)

    Spectra

    Mass Spec (NIST) Not Available Spectra

    Taxonomy

    Description This compound belongs to the class of organic compounds known as n-arylpiperazines. These are organic compounds containing a piperazine ring where the nitrogen ring atom carries an aryl group. Kingdom Organic compounds Super Class Organoheterocyclic compounds Class Diazinanes Sub Class Piperazines Direct Parent N-arylpiperazines Alternative Parents Quinazolinamines / Anisoles / Dialkylarylamines / Alkyl aryl ethers / Aminopyrimidines and derivatives / Imidolactams / Tetrahydrofurans / Tertiary carboxylic acid amides / Heteroaromatic compounds / Amino acids and derivativesOxacyclic compounds / Azacyclic compounds / Dialkyl ethers / Primary amines / Organic oxides / Carbonyl compounds / Organopnictogen compounds / Hydrocarbon derivatives show 8 more Substituents N-arylpiperazine / Quinazolinamine / Diazanaphthalene / Quinazoline / Anisole / Dialkylarylamine / Alkyl aryl ether / Aminopyrimidine / Pyrimidine / ImidolactamBenzenoid / Heteroaromatic compound / Tetrahydrofuran / Tertiary carboxylic acid amide / Amino acid or derivatives / Carboxamide group / Carboxylic acid derivative / Dialkyl ether / Ether / Oxacycle / Azacycle / Organic oxygen compound / Amine / Organic nitrogen compound / Hydrocarbon derivative / Carbonyl group / Organonitrogen compound / Organooxygen compound / Primary amine / Organopnictogen compound / Organic oxide / Aromatic heteropolycyclic compound show 22 more Molecular Framework Aromatic heteropolycyclic compounds External Descriptors primary amino compound, furans, quinazolines, piperazines (CHEBI:9445)

    Targets

    Binding Properties

    × Details Binding Properties1. Alpha-1A adrenergic receptor Kind Protein Organism Humans Pharmacological action Yes Actions Antagonist General Function Protein heterodimerization activity Specific Function This alpha-adrenergic receptor mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. Its effect is mediated by G(q) and G(11) prot… Gene Name ADRA1A Uniprot ID P35348 Uniprot Name Alpha-1A adrenergic receptor Molecular Weight 51486.005 Da

    1. Chapple CR: Medical therapy and quality of life. Eur Urol. 1998;34 Suppl 2:10-7; discussion 46.
    2. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5.
    3. Lee E, Lee C: Clinical comparison of selective and non-selective alpha 1A-adrenoreceptor antagonists in benign prostatic hyperplasia: studies on tamsulosin in a fixed dose and terazosin in increasing doses. Br J Urol. 1997 Oct;80(4):606-11.
    4. Michel MC, Grubbel B, Taguchi K, Verfurth F, Otto T, Kropfl D: Drugs for treatment of benign prostatic hyperplasia: affinity comparison at cloned alpha 1-adrenoceptor subtypes and in human prostate. J Auton Pharmacol. 1996 Feb;16(1):21-8.
    5. Na YJ, Guo YL, Gu FL: Clinical comparison of selective and non-selective alpha 1A-adrenoceptor antagonists for bladder outlet obstruction associated with benign prostatic hyperplasia: studies on tamsulosin and terazosin in Chinese patients. The Chinese Tamsulosin Study Group. J Med. 1998;29(5-6):289-304.
    6. Roehrborn CG, Schwinn DA: Alpha1-adrenergic receptors and their inhibitors in lower urinary tract symptoms and benign prostatic hyperplasia. J Urol. 2004 Mar;171(3):1029-35.

    × Details Binding Properties2. Alpha-1B adrenergic receptor Kind Protein Organism Humans Pharmacological action Yes Actions Antagonist General Function Protein heterodimerization activity Specific Function This alpha-adrenergic receptor mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. Its effect is mediated by G(q) and G(11) prot… Gene Name ADRA1B Uniprot ID P35368 Uniprot Name Alpha-1B adrenergic receptor Molecular Weight 56835.375 Da

    1. Boyle P, Robertson C, Manski R, Padley RJ, Roehrborn CG: Meta-analysis of randomized trials of terazosin in the treatment of benign prostatic hyperplasia. Urology. 2001 Nov;58(5):717-22.
    2. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5.
    3. Simpson P: Stimulation of hypertrophy of cultured neonatal rat heart cells through an alpha 1-adrenergic receptor and induction of beating through an alpha 1- and beta 1-adrenergic receptor interaction. Evidence for independent regulation of growth and beating. Circ Res. 1985 Jun;56(6):884-94.
    4. Vincent J, Dachman W, Blaschke TF, Hoffman BB: Pharmacological tolerance to alpha 1-adrenergic receptor antagonism mediated by terazosin in humans. J Clin Invest. 1992 Nov;90(5):1763-8.

    × Details Binding Properties3. Alpha-1D adrenergic receptor Kind Protein Organism Humans Pharmacological action Yes Actions Antagonist General Function Alpha1-adrenergic receptor activity Specific Function This alpha-adrenergic receptor mediates its effect through the influx of extracellular calcium. Gene Name ADRA1D Uniprot ID P25100 Uniprot Name Alpha-1D adrenergic receptor Molecular Weight 60462.205 Da

    1. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5.

    ×

    Property Measurement pH Temperature (°C)
    IC 50 (nM) 17782.79 N/A N/A 21185626

    Details Binding Properties4. Potassium voltage-gated channel subfamily H member 2 Kind Protein Organism Humans Pharmacological action Unknown Actions Inhibitor General Function Voltage-gated potassium channel activity involved in ventricular cardiac muscle cell action potential repolarization Specific Function Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel. Channel properties are modulated by cAMP and subunit assembly. Mediates the rapidly activating component of the … Gene Name KCNH2 Uniprot ID Q12809 Uniprot Name Potassium voltage-gated channel subfamily H member 2 Molecular Weight 126653.52 Da Kind Protein Organism Humans Pharmacological action Unknown Actions Inhibitor General Function Voltage-gated potassium channel activity Specific Function Pore-forming (alpha) subunit of voltage-gated potassium channel. Elicits a slowly activating, rectifying current (By similarity). Channel properties may be modulated by cAMP and subunit assembly. Gene Name KCNH6 Uniprot ID Q9H252 Uniprot Name Potassium voltage-gated channel subfamily H member 6 Molecular Weight 109923.705 Da Kind Protein Organism Humans Pharmacological action Unknown Actions Inhibitor General Function Voltage-gated potassium channel activity Specific Function Pore-forming (alpha) subunit of voltage-gated potassium channel. Channel properties may be modulated by cAMP and subunit assembly. Gene Name KCNH7 Uniprot ID Q9NS40 Uniprot Name Potassium voltage-gated channel subfamily H member 7 Molecular Weight 134998.525 Da Kind Protein Organism Humans Pharmacological action Yes Actions Inducer General Function Type iii transforming growth factor beta receptor binding Specific Function Multifunctional protein that controls proliferation, differentiation and other functions in many cell types. Many cells synthesize TGFB1 and have specific receptors for it. It positively and negati… Gene Name TGFB1 Uniprot ID P01137 Uniprot Name Transforming growth factor beta-1 Molecular Weight 44340.685 Da

    1. Papadopoulos G, Vlachodimitropoulos D, Kyroudi A, Kouloukoussa M, Perrea D, Mitropoulos D: Terazosin treatment induces caspase-3 expression in the rat ventral prostate. J Clin Med Res. 2013 Apr;5(2):127-31. doi: 10.4021/jocmr1215w. Epub 2013 Feb 25.
    2. Glassman DT, Chon JK, Borkowski A, Jacobs SC, Kyprianou N: Combined effect of terazosin and finasteride on apoptosis, cell proliferation, and transforming growth factor-beta expression in benign prostatic hyperplasia. Prostate. 2001 Jan 1;46(1):45-51.

    Transporters

    Kind Protein Organism Humans Pharmacological action Unknown Actions Inhibitor General Function Xenobiotic-transporting atpase activity Specific Function Energy-dependent efflux pump responsible for decreased drug accumulation in multidrug-resistant cells. Gene Name ABCB1 Uniprot ID P08183 Uniprot Name Multidrug resistance protein 1 Molecular Weight 141477.255 Da ×Unlock Data

    There is additional data available for commercial users including Adverse Effects, Contraindications, and Blackbox Warnings. Contact us to learn more about these and other features.

    Learn more

    Drug created on June 13, 2005 07:24 / Updated on February 02, 2020 04:29

  • tell your doctor if you have or have ever had prostate cancer.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking terazosin, call your doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking terazosin. If you need to have eye surgery at any time during or after your treatment, be sure to tell your doctor that you are taking or have taken terazosin.
  • you should know that terazosin may make you drowsy or dizzy. Do not drive a car, operate machinery or perform dangerous tasks for 12 hours after the first time you take terazosin or after your dose is increased, and until you know how this medication affects you.
  • you should know that terazosin may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking terazosin, when your dose is increased, or when treatment with terazosin is stopped for several days and then restarted. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. If you experience these symptoms, sit or lie down. If these symptoms do not improve, call your doctor.
  • talk to your doctor about the risks and benefits of taking terazosin if you are 65 years of age or older. Older adults should not usually take terazosin to treat high blood pressure, because it is not as safe or effective as other medications that can be used to treat the same condition.
  • About terazosin

    Type of medicine An alpha-blocker
    Used for Enlargement of the prostate gland in men; high blood pressure
    Also called Hytrin®; Benph®
    Available as Tablets

    Terazosin belongs to a group of medicines known as alpha-blockers. It works by blocking the action of certain nerve impulses. This blocking action is useful in two different medical conditions. It is used to help control the symptoms of prostate gland enlargement in men, and it is also prescribed to reduce high blood pressure in people with hypertension.

    The prostate gland commonly becomes larger in older men. Prostate gland enlargement is also called benign prostatic hyperplasia (BPH). The prostate gland is situated close to the bladder, so its enlargement can cause problems with passing urine. Common symptoms that are experienced are having to wait before your urine starts to flow, taking longer at the toilet, dribbling urine, and a feeling that your bladder is not quite empty. Terazosin works by relaxing the muscles around your bladder and prostate gland so that you can pass urine more easily.

    Terazosin works in high blood pressure by widening (relaxing) blood vessel walls. This lowers your blood pressure and allows blood to circulate more freely around your body.

    Before taking terazosin

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

    • If you ever feel dizzy or faint when you stand up, or if you have ever fainted after passing urine.
    • If you need to have cataract eye surgery.
    • If you are pregnant or breastfeeding.
    • If you have ever had an allergic reaction to a medicine.
    • If you are taking or using 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 terazosin

    • Before you start the treatment, read the manufacturer’s printed information leaflet from inside the pack. It will give you more information about terazosin and will provide you with a full list of the side-effects which you may experience from taking it.
    • Take terazosin exactly as your doctor tells you to. Swallow the tablet with a drink of water. You can take terazosin either before or after a meal.
    • There are several strengths of terazosin tablet available: 1 mg, 2 mg, 5 mg, and 10 mg. When you first start the treatment, your doctor may give you a low dose which will then later be increased. This allows your doctor to make sure that you have the dose that helps your condition and avoids any unwanted symptoms.
    • Your first dose of terazosin may make you feel dizzy or faint, so it is important that you take it just before you go to bed. If you feel dizzy or weary, or if you start sweating, remain lying down until these symptoms have completely gone.
    • Take terazosin once every day. After the first dose, you can take your dose at a time of day that best suits you. You should, however, try to take your doses at the same time of day each day, as this will help you to remember to take the tablets regularly.
    • If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, skip the forgotten dose. Do not take two doses at the same time to make up for a missed dose.

    Getting the most from your treatment

    • Terazosin can cause dizziness, particularly when you first start taking it. This may affect your ability to drive. Make sure your reactions are normal before you drive or do things which would be dangerous if you were not fully alert.
    • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. Your doctor is likely to want to take your blood pressure from time to time, particularly when you first start the treatment.
    • You are advised not to drink alcohol while you are on terazosin. Alcohol increases the risk of side-effects from terazosin, such as feeling faint or dizzy.
    • If you are taking terazosin for urinary symptoms, consider reducing or stopping the amount of caffeine you drink (commonly found in tea, coffee and cola). Caffeine can make your symptoms worse, so drinking less of these things may benefit you. Also, if you are a smoker, stopping smoking may significantly improve your symptoms. This is because nicotine irritates the bladder. You can ask your doctor for advice on quitting.
    • If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking terazosin. This is because your blood pressure may drop suddenly if you have an anaesthetic. If you are having cataract surgery, it is particularly important that you tell your surgeon you are on terazosin. This is because an eye problem known as ‘floppy iris syndrome’ has developed in some people and your doctor may advise you to stop taking terazosin for a short while.
    • If you buy any medicines check with a pharmacist that they are suitable to take with your other medicines. Some painkillers called non-steroidal anti-inflammatory drugs (NSAIDs) can reduce the blood pressure-lowering effect of terazosin.

    Can terazosin 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 terazosin. 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 terazosin side-effects (these affect less than 1 in 10 people) What can I do if I experience this?
    Feeling tired, dizzy or faint, blurred vision Do not drive and do not use tools or machines while affected
    Feeling light-headed when getting up from a lying or sitting position Getting up more slowly may help. If you begin to feel dizzy, lie down so that you do not faint, then sit for a few moments to prevent the dizziness returning
    Feeling sick Stick to simple foods – avoid rich or spicy meals
    The sensation of having a ‘thumping heart’ (palpitations), blocked nose, swollen hands or feet If any of these become troublesome, speak with your doctor

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

    How to store terazosin

    • Keep all medicines out of the reach and sight of children.
    • Store in a cool, dry place, away from direct heat and light.

    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. 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.

    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.

    Terazosin Side Effects

    Visit your doctor or health care professional for regular checks on your progress. Check your blood pressure regularly. Ask your doctor or health care professional what your blood pressure should be and when you should contact him or her.

    Drowsiness and dizziness are more likely to occur after the first dose, after an increase in dose, or during hot weather or exercise. These effects can decrease once your body adjusts to this medicine. Do not drive, use machinery, or do anything that needs mental alertness until you know how this drug affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol can make you more drowsy and dizzy. Avoid alcoholic drinks.

    Do not treat yourself for coughs, colds, or pain while you are taking this medicine without asking your doctor or health care professional for advice. Some ingredients may increase your blood pressure.

    Your mouth may get dry. Chewing sugarless gum or sucking hard candy, and drinking plenty of water may help. Contact your doctor if the problem does not go away or is severe.

    For males, contact your doctor or health care professional right away if you have an erection that lasts longer than 4 hours or if it becomes painful. This may be a sign of a serious problem and must be treated right away to prevent permanent damage.

    About the author

    Leave a Reply

    Your email address will not be published. Required fields are marked *