- Before taking vardenafil,
- CLINICAL PHARMACOLOGY
- Mechanism Of Action
- Effects On Blood Pressure
- Effects On Blood Pressure And Heart Rate When LEVITRA Is Combined With Nitrates
- Blood Pressure Effects In Patients On Stable Alpha-Blocker Treatment
- Blood Pressure Effects In Normotensive Men After Forced Titration With Alpha-Blockers
- Effects On Cardiac Electrophysiology
- Effects On Exercise Treadmill Test In Patients With Coronary Artery Disease (CAD)
- Effects On Eye
- Effects On Sperm Motility/Morphology
- Pharmacokinetics In Specific Populations
- Clinical Studies
- Uses and risks of Vardenafil, or Levitra
The following serious adverse reactions with the use of LEVITRA (vardenafil) are discussed elsewhere in the labeling:
- Cardiovascular Effects
- Effects on Eye
- Sudden Hearing Loss
- QT Prolongation
Clinical Studies Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
LEVITRA was administered to over 4430 men (mean age 56, range 18-89 years; 81% White, 6% Black, 2% Asian, 2% Hispanic and 9% Other) during controlled and uncontrolled clinical trials worldwide. Over 2200 patients were treated for 6 months or longer and 880 patients were treated for at least 1 year.
In placebo-controlled clinical trials, the discontinuation rate due to adverse events was 3.4% for LEVITRA compared to 1.1% for placebo.
When LEVITRA was taken as recommended in placebo-controlled clinical trials, the following adverse reactions were reported (see Table 1).
Table 1: Adverse Reactions Reported By ≥2% of Patients Treated with LEVITRA and More Frequent on Drug than Placebo in Fixed and Flexiblea Dose Randomized, Controlled Trials of 5 mg, 10 mg, or 20 mg Vardenafil
|Adverse Reaction||Percentage of Patients Reporting Reactions|
N = 1199
N = 2203
|Increased Creatine Kinase||1%||2%|
| a) Flexible dose studies started all patients at LEVITRA 10 mg and allowed decrease in dose to 5 mg or increase in dose to 20 mg based on side effects and efficacy.
b) All the events listed in the above table were deemed to be adverse drug reactions with the exception of accidental injury.
Back pain was reported in 2.0% of patients treated with LEVITRA and 1.7% of patients on placebo
Placebo-controlled trials suggested a dose effect in the incidence of some adverse reactions (headache, flushing, dyspepsia, nausea, and rhinitis) over the 5 mg, 10 mg, and 20 mg doses of LEVITRA.
All Vardenafil Studies
LEVITRA film-coated tablets and vardenafil orally disintegrating tablets have been administered to over 17,000 men (mean age 54.5, range 18.89 years; 70% White, 5% Black, 13% Asian, 4% Hispanic and 8% Other) during controlled and uncontrolled clinical trials worldwide. The number of patients treated for 6 months or longer was 3357, and 1350 patients were treated for at least 1 year.
In the placebo-controlled clinical trials for LEVITRA film-coated tablets and vardenafil orally disintegrating tablets, the discontinuation rate due to adverse events was 1.9% for vardenafil compared to 0.8% for placebo.
The following section identifies additional, less frequent adverse reactions (<2%) reported during the clinical development of LEVITRA film-coated tablets and vardenafil orally disintegrating tablets. Excluded from this list are those adverse reactions that are infrequent and minor, those events that may be commonly observed in the absence of drug therapy, and those events that are not reasonably associated with the drug:
Body as a whole: allergic edema and angioedema, feeling unwell, allergic reactions, chest pain
Auditory: tinnitus, vertigo
Cardiovascular: palpitation, tachycardia, angina pectoris, myocardial infarction, ventricular tachyarrhythmias, hypotension
Digestive: nausea, gastrointestinal and abdominal pain, dry mouth, diarrhea, gastroesophageal reflux disease, gastritis, vomiting, increase in transaminases
Musculoskeletal: increase in creatine phosphokinase (CPK), increased muscle tone and cramping, myalgia
Nervous: paresthesia and dysesthesia, somnolence, sleep disorder, syncope, amnesia, seizure
Respiratory: dyspnea, sinus congestion
Skin and appendages: erythema, rash
Ophthalmologic: visual disturbance, ocular hyperemia, visual color distortions, eye pain and eye discomfort, photophobia, increase in intraocular pressure, conjunctivitis
Urogenital: increase in erection, priapism
The following adverse reactions have been identified during post approval use of LEVITRA. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency or establish a causal relationship to drug exposure.
Non-arteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision, has been reported rarely postmarketing in temporal association with the use of PDE5 inhibitors, including vardenafil. Most, but not all, of these patients had underlying anatomic or vascular risk factors for development of NAION, including but not necessarily limited to: low cup to disc ratio (“crowded disc”), age over 50, diabetes, hypertension, coronary artery disease, hyperlipidemia and smoking .
Visual disturbances including vision loss (temporary or permanent), such as visual field defect, retinal vein occlusion, and reduced visual acuity, have also been reported rarely in postmarketing experience. It is not possible to determine whether these events are related directly to the use of vardenafil.
Seizure, seizure recurrence and transient global amnesia have been reported postmarketing in temporal association with vardenafil.
Cases of sudden decrease or loss of hearing have been reported postmarketing in temporal association with the use of PDE5 inhibitors, including vardenafil. In some cases, medical conditions and other factors were reported that may have also played a role in the otologic adverse events. In many cases, medical follow-up information was limited. It is not possible to determine whether these reported events are related directly to the use of vardenafil, to the patient’s underlying risk factors for hearing loss, a combination of these factors, or to other factors .
Read the entire FDA prescribing information for Levitra (Vardenafil HCl)
Before taking vardenafil,
- tell your doctor and pharmacist if you are allergic to vardenafil,any other medications. or any of the ingredients in vardenafil tablets. Ask your pharmacist for a list of the ingredients.
- do not take vardenafil if you are taking or have recently taken riociguat (Adempas) or nitrates such as isosorbide dinitrate (Dilatrate-SR, Isordil, in BiDil), isosorbide mononitrate (Monoket), and nitroglycerin (Minitran, Nitro-Dur, Nitromist, Nitrostat, others). Nitrates come as tablets, sublingual (under the tongue) tablets, sprays, patches, pastes, and ointments. Ask your doctor if you are not sure if any of your medications contain nitrates.
- do not take street drugs containing nitrates such as amyl nitrate and butyl nitrate (‘poppers’) while taking vardenafil.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: alpha blockers such as alfuzosin (Uroxatral), doxazosin (Cardura), prazosin (Minipress), tamsulosin (Flomax, in Jalyn), and terazosin; amiodarone (Cordarone, Pacerone); antifungals such as fluconazole (Diflucan), itraconazole (Onmel, Sporanox), and ketoconazole (Nizoral); clarithromycin (Biaxin, in Prevpac); disopyramide (Norpace); erythromycin (E.E.S., E-Mycin, Erythrocin); haloperidol (Haldol); HIV protease inhibitors including atazanavir (Reyataz, in Evotaz), indinavir (Crixivan), ritonavir (Norvir, in Kaletra), and saquinavir (Invirase); medications for high blood pressure or irregular heartbeat; other medications or treatments for erectile dysfunction; methadone (Dolophine, Methadose); moxifloxacin (Avelox); pimozide (Orap); procainamide; quinidine (in Nuedexta); sotalol (Betapace, Sorine, Sotylize); thioridazine; and verapamil (Calan, Covera, Verelan, others). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may interact with vardenafil, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
- tell your doctor what herbal products you are taking, especially St. John’s wort.
- tell your doctor if you smoke and if you have ever had an erection that lasted more than 4 hours. Also tell your doctor if you have or have ever had a condition that affects the shape of the penis, such as angulation, cavernosal fibrosis, or Peyronie’s disease; diabetes; high cholesterol; high or low blood pressure; irregular heartbeat; a heart attack; angina (chest pain); a stroke; ulcers in the stomach or intestine; a bleeding disorder; blood cell problems such as sickle cell anemia (a disease of the red blood cells), multiple myeloma (cancer of the plasma cells), or leukemia (cancer of the white blood cells); seizures; and liver, kidney, or heart disease. Also tell your doctor if you or any of your family members have or have ever had long QT syndrome (a heart condition) or retinitis pigmentosus (an eye disease) or if you have ever had severe vision loss, especially if you were told that the vision loss was caused by a blockage of blood flow to the nerves that help you see. Tell your doctor if you have ever been advised by a health care professional to avoid sexual activity for medical reasons.
- you should know that vardenafil is only for use in males. Women should not take vardenafil, especially if they are or could become pregnant or are breast-feeding. If a pregnant woman takes vardenafil, she should call her doctor.
- if you are having surgery, including dental surgery or any dental procedure, tell the doctor or dentist that you are taking vardenafil.
- you should know that sexual activity may be a strain on your heart, especially if you have heart disease. If you have chest pain during sexual activity, call your doctor immediately and avoid sexual activity until your doctor tells you otherwise.
- tell all your health care providers that you are taking vardenafil. If you ever need emergency medical treatment for a heart problem, the health care providers who treat you will need to know when you last took vardenafil.
- if you have phenylketonuria (PKU, an inherited condition in which a special diet must be followed to prevent mental retardation), you should know that the rapidly disintegrating tablets are sweetened with aspartame, a source of phenylalanine.
- if you have fructose intolerance (an inherited condition in which the body lacks the protein needed to break down fructose,), you should know that the the rapidly disintegrating tablets are sweetened with sorbitol. Tell your doctor if you have fructose intolerance.
Mechanism Of Action
Penile erection is a hemodynamic process initiated by the relaxation of smooth muscle in the corpus cavernosum and its associated arterioles. During sexual stimulation, nitric oxide is released from nerve endings and endothelial cells in the corpus cavernosum. Nitric oxide activates the enzyme guanylate cyclase resulting in increased synthesis of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum. The cGMP in turn triggers smooth muscle relaxation, allowing increased blood flow into the penis, resulting in erection. The tissue concentration of cGMP is regulated by both the rates of synthesis and degradation via phosphodiesterases (PDEs). The most abundant PDE in the human corpus cavernosum is the cGMP-specific phosphodiesterase type 5 (PDE5); therefore, the inhibition of PDE5 enhances erectile function by increasing the amount of cGMP. Because sexual stimulation is required to initiate the local release of nitric oxide, the inhibition of PDE5 has no effect in the absence of sexual stimulation.
In vitro studies have shown that vardenafil is a selective inhibitor of PDE5. The inhibitory effect of vardenafil is more selective on PDE5 than for other known phosphodiesterases (>15-fold relative to PDE6, >130-fold relative to PDE1, >300-fold relative to PDE11, and >1,000-fold relative to PDE2, 3, 4, 7, 8, 9, and 10).
Effects On Blood Pressure
In a clinical pharmacology study of patients with erectile dysfunction, single doses of vardenafil 20 mg caused a mean maximum decrease in supine blood pressure of 7 mmHg systolic and 8 mmHg diastolic (compared to placebo), accompanied by a mean maximum increase of heart rate of 4 beats per minute. The maximum decrease in blood pressure occurred between 1 and 4 hours after dosing. Following multiple dosing for 31 days, similar blood pressure responses were observed on Day 31 as on Day 1. Vardenafil may add to the blood pressure lowering effects of antihypertensive agents .
Effects On Blood Pressure And Heart Rate When LEVITRA Is Combined With Nitrates
A study was conducted in which the blood pressure and heart rate response to 0.4 mg nitroglycerin (NTG) sublingually was evaluated in 18 healthy subjects following pretreatment with LEVITRA 20 mg at various times before NTG administration. LEVITRA 20 mg caused an additional time-related reduction in blood pressure and increase in heart rate in association with NTG administration. The blood pressure effects were observed when LEVITRA 20 mg was dosed 1 or 4 hours before NTG and the heart rate effects were observed when 20 mg was dosed 1, 4, or 8 hours before NTG. Additional blood pressure and heart rate changes were not detected when LEVITRA 20 mg was dosed 24 hours before NTG. (See Figure 1.)
Figure 1: Placebo-subtracted point estimates (with 90% CI) of mean maximal blood pressure and heart rate effects of pre-dosing with vardenafil 20 mg at 24, 8, 4, and 1 hour before 0.4 mg NTG sublingually
Because the disease state of patients requiring nitrate therapy is anticipated to increase the likelihood of hypotension, the use of vardenafil by patients on nitrate therapy or on nitric oxide donors is contraindicated .
Blood Pressure Effects In Patients On Stable Alpha-Blocker Treatment
Three clinical pharmacology studies were conducted in patients with benign prostatic hyperplasia (BPH) on stable-dose alpha-blocker treatment, consisting of alfuzosin, tamsulosin or terazosin.
This study was designed to evaluate the effect of 5 mg vardenafil compared to placebo when administered to BPH patients on chronic alpha-blocker therapy in two separate cohorts: tamsulosin 0.4 mg daily (cohort 1, n=21) and terazosin 5 or 10 mg daily (cohort 2, n=21). The design was a randomized, double blind, cross-over study with four treatments: vardenafil 5 mg or placebo administered simultaneously with the alpha-blocker and vardenafil 5 mg or placebo administered 6 hours after the alpha-blocker. Blood pressure and pulse were evaluated over the 6-hour interval after vardenafil dosing. For blood pressure (BP) results see Table 2. One patient after simultaneous treatment with 5 mg vardenafil and 10 mg terazosin exhibited symptomatic hypotension with standing blood pressure of 80/60 mmHg occurring one hour after administration and subsequent mild dizziness and moderate lightheadedness lasting for 6 hours. For vardenafil and placebo, five and two patients, respectively, experienced a decrease in standing systolic blood pressure (SBP) of >30 mmHg following simultaneous administration of terazosin. Hypotension was not observed when vardenafil 5 mg and terazosin were administered 6 hours apart. Following simultaneous administration of vardenafil 5 mg and tamsulosin, two patients had a standing SBP of <85 mmHg. A decrease in standing SBP of >30 mmHg was observed in two patients on tamsulosin receiving simultaneous vardenafil and in one patient receiving simultaneous placebo treatment. When tamsulosin and vardenafil 5 mg were separated by 6 hours, two patients had a standing SBP <85 mmHg and one patient had a decrease in SBP of >30 mmHg. There were no severe adverse events related to hypotension reported during the study. There were no cases of syncope.
Table 2: Mean (95% C.I.) maximal change from baseline in systolic blood pressure (mmHg) following vardenafil 5 mg in BPH patients on stable alpha-blocker therapy (Study 1)
Blood pressure effects (standing SBP) in normotensive men on stable dose of tamsulosin 0.4 mg following simultaneous administration of vardenafil 5 mg or placebo, or following administration of vardenafil 5 mg or placebo separated by 6 hours are shown in Figure 2. Blood pressure effects (standing SBP) in normotensive men on stable dose terazosin (5 or 10 mg) following simultaneous administration of vardenafil 5 mg or placebo, or following administration of vardenafil 5 mg or placebo separated by 6 hours, are shown in Figure 3.
Figure 2: Mean change from baseline in standing systolic blood pressure (mmHg) over 6 hour interval following simultaneous or 6 hr separation administration of vardenafil 5 mg or placebo with stable dose tamsulosin 0.4 mg in normotensive BPH patients (Study 1)
Figure 3: Mean change from baseline in standing systolic blood pressure (mmHg) over 6 hour interval following simultaneous or 6 hr separation administration of vardenafil 5 mg or placebo with stable dose terazosin (5 or 10 mg) in normotensive BPH patients (Study 1)
This study was designed to evaluate the effect of 10 mg vardenafil (stage 1) and 20 mg vardenafil (stage 2) compared to placebo, when administered to a single cohort of BPH patients (n=23) on stable therapy with tamsulosin 0.4 mg or 0.8 mg daily for at least four weeks. The design was a randomized, double blind, two-period cross-over study. Vardenafil or placebo was given simultaneously with tamsulosin. Blood pressure and pulse were evaluated over the 6hour interval after vardenafil dosing. For BP results see Table 3. One patient experienced a decrease from baseline in standing SBP of >30 mmHg following vardenafil 10 mg. There were no other instances of outlier blood pressure values (standing SBP <85 mmHg or decrease from baseline in standing SBP of >30 mmHg). Three patients reported dizziness following vardenafil 20 mg. There were no cases of syncope.
Table 3: Mean (95% C.I.) maximal change from baseline in systolic blood pressure (mmHg) following vardenafil 10 and 20 mg in BPH patients on stable alpha-blocker therapy with tamsulosin 0.4 or 0.8 mg daily (Study 2)
Blood pressure effects (standing SBP) in normotensive men on stable dose of tamsulosin 0.4 mg following simultaneous administration of vardenafil 10 mg, vardenafil 20 mg or placebo are shown in Figure 4.
Figure 4: Mean change from baseline in standing systolic blood pressure (mmHg) over 6 hour interval following simultaneous administration of vardenafil 10 mg (Stage 1), vardenafil 20 mg (Stage 2), or placebo with stable dose tamsulosin 0.4 mg in normotensive BPH patients (Study 2)
This study was designed to evaluate the effect of single doses of 5 mg vardenafil (stage 1) and 10 mg vardenafil (stage 2) compared to placebo, when administered to a single cohort of BPH patients (n=24) on stable therapy with alfuzosin 10 mg daily for at least four weeks. The design was a randomized, double blind, 3period cross-over study. Vardenafil or placebo was administered 4 hours after the administration of alfuzosin. Blood pressure and pulse were evaluated over a 10-hour interval after dosing of vardenafil or placebo. For BP results see Table 4.
Table 4: Mean (95% C.I.) maximal change from baseline in systolic blood pressure (mmHg) following vardenafil 5 and 10 mg in BPH patients on stable alpha-blocker therapy with alfuzosin 10 mg daily (Study 3)
One patient experienced decreases from baseline in standing systolic blood pressure >30 mm Hg after administration of vardenafil 5 mg film-coated tablet and vardenafil 10 mg film-coated tablet. No instances of standing systolic blood pressure <85 mm Hg were observed during this study. Four patients, one dosed with placebo, two dosed with vardenafil 5 mg film-coated tablets and one dosed with vardenafil 10 mg film-coated tablets, reported dizziness. Blood pressure effects (standing SBP) in normotensive men on a stable dose of alfuzosin 10 mg following administration of vardenafil 5 mg, vardenafil 10 mg, or placebo separated by 4 hours, are shown in Figure 5.
Figure 5: Mean change from baseline in standing systolic blood pressure (mmHg) over 6 hour interval following 4 hr separation administration of vardenafil 5 mg (stage 1), vardenafil 10 mg (stage 2) or placebo with stable dose
Blood Pressure Effects In Normotensive Men After Forced Titration With Alpha-Blockers
Two randomized, double blind, placebo-controlled clinical pharmacology studies with healthy normotensive volunteers (age range, 45-74 years) were performed after forced titration of the alpha-blocker terazosin to 10 mg daily over 14 days (n=29), and after initiation of tamsulosin 0.4 mg daily for five days (n=24). There were no severe adverse events related to hypotension in either study. Symptoms of hypotension were a cause for withdrawal in 2 subjects receiving terazosin and in 4 subjects receiving tamsulosin. Instances of outlier blood pressure values (defined as standing SBP <85 mmHg and/or a decrease from baseline of standing SBP >30 mmHg) were observed in 9/24 subjects receiving tamsulosin and 19/29 receiving terazosin. The incidence of subjects with standing SBP <85 mmHg given vardenafil and terazosin to achieve simultaneous Tmax led to early termination of that arm of the study. In most (7/8) of these subjects, instances of standing SBP <85 mmHg were not associated with symptoms. Among subjects treated with terazosin, outlier values were observed more frequently when vardenafil and terazosin were given to achieve simultaneous Tmax than when dosing was administered to separate Tmax by 6 hours. There were 3 cases of dizziness observed with concomitant administration of terazosin and vardenafil. Seven subjects experienced dizziness mainly occurring with simultaneous Tmax administration of tamsulosin. There were no cases of syncope.
Table 5: Mean (95% C.I.) maximal change in baseline in systolic blood pressure (mmHg) following vardenafil 10 and 20 mg in healthy volunteers on daily alpha-blocker therapy
Figure 6: Mean change from baseline in standing systolic blood pressure (mmHg) over 6 hour interval following simultaneous or 6 hr separation administration of vardenafil 10 mg, vardenafil 20 mg or placebo with terazosin (10 mg) in healthy volunteers
Figure 7: Mean change from baseline in standing systolic blood pressure (mmHg) over 6 hour interval following simultaneous or 6 hr separation administration of vardenafil 10 mg, vardenafil 20 mg or placebo with tamsulosin
Effects On Cardiac Electrophysiology
The effect of 10 mg and 80 mg vardenafil on QT interval was evaluated in a single-dose, double-blind, randomized, placebo-and active-controlled (moxifloxacin 400 mg) crossover study in 59 healthy males (81% White, 12% Black, 7% Hispanic) aged 45-60 years. The QT interval was measured at one hour post dose because this time point approximates the average time of peak vardenafil concentration. The 80 mg dose of LEVITRA (four times the highest recommended dose) was chosen because this dose yields plasma concentrations covering those observed upon co-administration of a low-dose of LEVITRA (5 mg) and 600 mg BID of ritonavir. Of the CYP3A4 inhibitors that have been studied, ritonavir causes the most significant drug-drug interaction with vardenafil. Table 6 summarizes the effect on mean uncorrected QT and mean corrected QT interval (QTc) with different methods of correction (Fridericia and a linear individual correction method) at one hour post-dose. No single correction method is known to be more valid than the other. In this study, the mean increase in heart rate associated with a 10 mg dose of LEVITRA compared to placebo was 5 beats/minute and with an 80 mg dose of LEVITRA the mean increase was 6 beats/minute.
Table 6. Mean QT and QTc changes in msec (90% CI) from baseline relative to placebo at 1 hour post-dose with different methodologies to correct for the effect of heart rate.
Therapeutic and supratherapeutic doses of vardenafil and the active control moxifloxacin produced similar increases in QTc interval. This study, however, was not designed to make direct statistical comparisons between the drug or the dose levels. The clinical impact of these QTc changes is unknown .
In a separate postmarketing study of 44 healthy volunteers, single doses of 10 mg LEVITRA resulted in a placebo- subtracted mean change from baseline of QTcF (Fridericia correction) of 5 msec (90% CI: 2,8). Single doses of gatifloxacin 400mg resulted in a placebo-subtracted mean change from baseline QTcF of 4 msec (90% CI: 1,7). When LEVITRA 10mg and gatifloxacin 400 mg were co-administered, the mean QTcF change from baseline was additive when compared to either drug alone and produced a mean QTcF change of 9 msec from baseline (90% CI: 6,11). The clinical impact of these QT changes is unknown .
Effects On Exercise Treadmill Test In Patients With Coronary Artery Disease (CAD)
In two independent trials that assessed 10 mg (n=41) and 20 mg (n=39) vardenafil, respectively, vardenafil did not alter the total treadmill exercise time compared to placebo. The patient population included men aged 40-80 years with stable exercise-induced angina documented by at least one of the following: 1) prior history of myocardial infarction (MI), coronary artery bypass graft (CABG), percutaneous transluminal coronary angioplasty (PTCA), or stenting (not within 6 months); 2) positive coronary angiogram showing at least 60% narrowing of the diameter of at least one major coronary artery; or 3) a positive stress echocardiogram or stress nuclear perfusion study.
Results of these studies showed that LEVITRA did not alter the total treadmill exercise time compared to placebo (10 mg LEVITRA vs. placebo: 433±109 and 426±105 seconds, respectively; 20 mg LEVITRA vs. placebo: 414±114 and 411±124 seconds, respectively). The total time to angina was not altered by LEVITRA when compared to placebo (10 mg LEVITRA vs. placebo: 291±123 and 292±110 seconds; 20 mg LEVITRA vs. placebo: 354±137 and 347±143 seconds, respectively). The total time to 1 mm or greater ST-segment depression was similar to placebo in both the 10 mg and the 20 mg LEVITRA groups (10 mg LEVITRA vs. placebo: 380±108 and 334±108 seconds; 20 mg LEVITRA vs. placebo: 364±101 and 366±105 seconds, respectively).
Effects On Eye
Single oral doses of phosphodiesterase inhibitors have demonstrated transient dose-related impairment of color discrimination (blue/green) using the Farnsworth-Munsell 100-hue test and reductions in electroretinogram (ERG) b-wave amplitudes, with peak effects near the time of peak plasma levels. These findings are consistent with the inhibition of PDE6 in rods and cones, which is involved in phototransduction in the retina. The findings were most evident one hour after administration, diminishing but still present 6 hours after administration. In a single dose study in 25 normal males, LEVITRA 40 mg, twice the maximum daily recommended dose, did not alter visual acuity, intraocular pressure, fundoscopic and slit lamp findings.
In another double-blind, placebo controlled clinical trial, at least 15 doses of 20 mg vardenafil were administered over 8 weeks versus placebo to 52 males. Thirty-two (32) males (62%) of the patients completed the trial. Retinal function was measured by ERG and FM-100 test 2, 6 and 24 hours after dosing. The trial was designed to detect changes in retinal function that might occur in more than 10% of patients. Vardenafil did not produce clinically significant ERG or FM-100 effects in healthy men compared to placebo. Two patients on vardenafil in the trial reported episodes of transient cyanopsia (objects appear blue).
Effects On Sperm Motility/Morphology
There was no effect on sperm motility or morphology after single 20 mg oral doses of vardenafil in healthy volunteers.
The pharmacokinetics of vardenafil are approximately dose proportional over the recommended dose range..
Mean vardenafil plasma concentrations measured after the administration of a single oral dose of 20 mg to healthy male volunteers are depicted in Figure 8.
Figure 8: Plasma Vardenafil Concentration (Mean ± SD) Curve for a Single 20 mg LEVITRA Dose
Vardenafil is rapidly absorbed with absolute bioavailability of approximately 15%. Maximum observed plasma concentrations after a single 20 mg dose in healthy volunteers are usually reached between 30 minutes and 2 hours (median 60 minutes) after oral dosing in the fasted state. Two food-effect studies were conducted which showed that high-fat meals caused a reduction in Cmax by 18%-50%.
The mean steady-state volume of distribution (Vss) for vardenafil is 208 L, indicating extensive tissue distribution. Vardenafil and its major circulating metabolite, M1, are highly bound to plasma proteins (about 95% for parent drug and M1). This protein binding is reversible and independent of total drug concentrations.
Following a single oral dose of 20 mg vardenafil in healthy volunteers, a mean of 0.00018% of the administered dose was obtained in semen 1.5 hours after dosing.
Vardenafil is metabolized predominantly by the hepatic enzyme CYP3A4, with contribution from the CYP3A5 and CYP2C isoforms. The major circulating metabolite, M1, results from desethylation at the piperazine moiety of vardenafil. M1 is subject to further metabolism. The plasma concentration of M1 is approximately 26% that of the parent compound. This metabolite shows a phosphodiesterase selectivity profile similar to that of vardenafil and an in vitro inhibitory potency for PDE5 28% of that of vardenafil. Therefore, M1 accounts for approximately 7% of total pharmacologic activity.
The total body clearance of vardenafil is 56 L/h, and the terminal half-life of vardenafil and its primary metabolite (M1) is approximately 4-5 hours. After oral administration, vardenafil is excreted as metabolites predominantly in the feces (approximately 91-95% of administered oral dose) and to a lesser extent in the urine (approximately 2-6% of administered oral dose).
Pharmacokinetics In Specific Populations
LEVITRA is not indicated for use in pediatric patients. Vardenafil trials were not conducted in the pediatric population.
In a healthy volunteer study of elderly males (≥65 years) and younger males (18–45 years), mean Cmax and AUC were 34% and 52% higher, respectively, in the elderly males .
In volunteers with mild hepatic impairment (Child-Pugh A), the Cmax and AUC following a 10 mg vardenafil dose were increased by 22% and 17%, respectively, compared to healthy control subjects. In volunteers with moderate hepatic impairment (Child-Pugh B), the Cmax and AUC following a 10 mg vardenafil dose were increased by 130% and 160%, respectively, compared to healthy control subjects. Vardenafil has not been evaluated in patients with severe (Child-Pugh C) hepatic impairment.
In male volunteers with CLcr = 50.80 mL/min, the pharmacokinetics of vardenafil were similar to those observed in a control group with CLcr >80 mL/min. In male volunteers with CLcr = 30.50 mL/min or CLcr<30 mL/min renal impairment groups, the AUC of vardenafil was 20.30% higher compared to that observed in a control group with CLcr>80 mL/min). Vardenafil pharmacokinetics have not been evaluated in patients requiring renal dialysis. .
LEVITRA was evaluated in four major double-blind, randomized, placebo-controlled, fixed-dose, parallel design, multicenter trials in 2431 men aged 20-83 (mean age 57 years; 78% White, 7% Black, 2% Asian, 3% Hispanic and 10% Other/Unknown). The doses of LEVITRA in these studies were 5 mg, 10 mg, and 20 mg. Two of these trials were conducted in the general erectile dysfunction (ED) population and two in special ED populations (one in patients with diabetes mellitus and one in post-prostatectomy patients). LEVITRA was dosed without regard to meals on an as needed basis in men with ED, many of whom had multiple other medical conditions. The primary endpoints were assessed at 3 months.
Primary efficacy assessment in all four major trials was by means of the Erectile Function (EF) Domain score of the validated International Index of Erectile Function (IIEF) Questionnaire and two questions from the Sexual Encounter Profile (SEP) dealing with the ability to achieve vaginal penetration (SEP2), and the ability to maintain an erection long enough for successful intercourse (SEP3).
In all four fixed-dose efficacy trials, LEVITRA showed clinically meaningful and statistically significant improvement in the EF Domain, SEP2, and SEP3 scores compared to placebo. The mean baseline EF Domain score in these trials was 11.8 (scores range from 0-30 where lower scores represent more severe disease). LEVITRA (5 mg, 10 mg, and 20 mg) was effective in all age categories (<45, 45 to <65, and ≥65 years) and was also effective regardless of race (White, Black, Other).
Trials In A General Erectile Dysfunction Population
In the major North American fixed-dose trial, 762 patients (mean age 57, range 20-83 years; 79% White, 13% Black, 4% Hispanic, 2% Asian and 2% Other) were evaluated. The mean baseline EF Domain scores were 13, 13, 13, 14 for the LEVITRA 5 mg, 10 mg, 20 mg and placebo groups, respectively. There was significant improvement (p <0.0001) at 3 months with LEVITRA (EF Domain scores of 18, 21, 21, for the 5 mg, 10 mg, and 20 mg dose groups, respectively) compared to the placebo group (EF Domain score of 15). The European trial (total N=803) confirmed these results. The improvement in mean score was maintained at all doses at 6 months in the North American trial.
In the North American trial, LEVITRA significantly improved the rates of achieving an erection sufficient for penetration (SEP2) at doses of 5 mg, 10 mg, and 20 mg compared to placebo (65%, 75%, and 80%, respectively, compared to a 52% response in the placebo group at 3 months; p <0.0001). The European trial confirmed these results.
LEVITRA demonstrated a clinically meaningful and statistically significant increase in the overall per-patient rate of maintenance of erection to successful intercourse (SEP3) (51% on 5 mg, 64% on 10 mg, and 65% on 20 mg, respectively, compared to 32% on placebo; p <0.0001) at 3 months in the North American trial. The European trial showed comparable efficacy. This improvement in mean score was maintained at all doses at 6 months in the North American trial.
Trial In Patients With ED And Diabetes Mellitus
LEVITRA demonstrated clinically meaningful and statistically significant improvement in erectile function in a prospective, fixed-dose (10 and 20 mg LEVITRA), double-blind, placebo-controlled trial of patients with diabetes mellitus (n=439; mean age 57 years, range 33-81; 80% White, 9% Black, 8% Hispanic, and 3% Other).
Significant improvements in the EF Domain were shown in this study (EF Domain scores of 17 on 10 mg LEVITRA and 19 on 20 mg LEVITRA compared to 13 on placebo; p <0.0001).
LEVITRA significantly improved the overall per-patient rate of achieving an erection sufficient for penetration (SEP2) (61% on 10 mg and 64% on 20 mg LEVITRA compared to 36% on placebo; p <0.0001).
LEVITRA demonstrated a clinically meaningful and statistically significant increase in the overall per-patient rate of maintenance of erection to successful intercourse (SEP3) (49% on 10 mg, 54% on 20 mg LEVITRA compared to 23% on placebo; p <0.0001).
Trial In Patients With ED After Radical Prostatectomy
LEVITRA demonstrated clinically meaningful and statistically significant improvement in erectile function in a prospective, fixed-dose (10 and 20 mg LEVITRA), double-blind, placebo-controlled trial in post-prostatectomy patients (n=427, mean age 60, range 44-77 years; 93% White, 5% Black, 2% Other).
Significant improvements in the EF Domain were shown in this study (EF Domain scores of 15 on 10 mg LEVITRA and 15 on 20 mg LEVITRA compared to 9 on placebo; p <0.0001).
LEVITRA significantly improved the overall per-patient rate of achieving an erection sufficient for penetration (SEP2) (47% on 10 mg and 48% on 20 mg LEVITRA compared to 22% on placebo; p <0.0001).
LEVITRA demonstrated a clinically meaningful and statistically significant increase in the overall per-patient rate of maintenance of erection to successful intercourse (SEP3) (37% on 10 mg, 34% on 20 mg LEVITRA compared to 10% on placebo; p <0.0001).
Uses and risks of Vardenafil, or Levitra
As with all medications, adverse effects and interactions can occur when using vardenafil.
One in 10 men will experience headache.
Other common side effects include:
- stuffy or runny nose
- stomach upset
In most cases, these disappear within a few hours.
Other potentially serious symptoms include:
- ringing in the ears, or sudden hearing loss
- irregular heartbeat
- swelling in the ankles, hands, or feet
- difficulty breathing
- chest pain
The patient should stop using vardenafil if these occur.
Rarely, an allergic reaction may occur. This can lead to hives, difficulty breathing, and swelling of the face, tongue, and throat. It can lead to shock, and it can be fatal. If these symptoms appear, it should be treated as a medical emergency.
Very rare side effects may include priapism, when an erection lasts longer than 4 hours. This can damage the penis. If an erection lasts too long, the individual should seek medical attention.
Visual disturbances can happen when blood pressure drops in the eye. The individual may see a blue tinge to objects, and they may have difficulty distinguishing between the colors green and blue.
Very rarely, there may be a sudden deterioration in vision in one or both eyes. This can indicate a heart condition, an existing eye problem, high cholesterol, diabetes, or hypertension.
If any sudden loss of vision occurs, the individual should stop taking the medication and seek medical help immediately.
Vision problems are most likely in patients with other conditions, such as heart or coronary artery disease, diabetes, and high cholesterol. Vision problems are more likely to happen if the person smokes, or if they are aged over 50 years.
Using vardenafil with some other drugs can lead to serious adverse effects.
Possible reactions include:
- a potentially dangerous drop in blood pressure, or hypotension
There is also a risk of stroke and heart attack.
A man should not use vardenafil if he is taking nitrate drugs, such as riociguat (Adempas), or other nitrate drugs for chest pain or heart problems.
It should not be used with the recreational drugs, amyl nitrate and butyl nitrate, also known as poppers.
Other drugs that may interact include, but are not limited to:
- antibiotic and antifungal medications
- other medications for erectile dysfunction
- drugs for prostate problems, blood pressure, or heart rhythm disorders
- medications for HIV or AIDS
Grapefruit juice contains a chemical that makes adverse effects more likely, so it should not be consumed while using vardenafil.