Geriatrics: A starting dose of 5 mg vardenafil hydrochloride tablets should be considered in patients ≥65 years of age [see Use in Specific Populations (8.5)].

Hepatic Impairment: For patients with moderate hepatic impairment (Child-Pugh B), a starting dose of 5 mg vardenafil hydrochloride tablets is recommended. The maximum dose in patients with moderate hepatic impairment should not exceed 10 mg.

Do not use vardenafil hydrochloride tablets in patients with severe hepatic impairment (Child-Pugh C) [ see Warnings and Precautions (5.8), Use in Specific Populations (8.6) and Clinical Pharmacology (12.3)] .

Renal Impairment: Do not use vardenafil hydrochloride tablets in patients on renal dialysis [see Warnings and Precautions (5.9), Use in Specific Populations (8.7) and Clinical Pharmacology (12.3)].

Nitrates: Concomitant use with nitrates and nitric oxide donors in any form is contraindicated [see Contraindications (4.1)]

Guanylate Cyclase (GC) Stimulators, such as riociguat: Concomitant use is contraindicated [see Contraindications (4.2)].

CYP3A4 Inhibitors: The dosage of vardenafil hydrochloride tablets may require adjustment in patients receiving potent CYP3A4 inhibitors such as ketoconazole, itraconazole, ritonavir, indinavir, saquinavir, atazanavir, cobicistat, and clarithromycin as well as in other patients receiving moderate CYP3A4 inhibitors such as erythromycin [see Drug Interactions (7.2 )].
If taking strong or moderate inhibitors of CYP3A4, the dose of vardenafil hydrochloride tablets should be adjusted as follows:

• Ritonavir: No more than 2.5 mg in a 72-hour period.
• Indinavir, saquinavir, atazanavir, ketoconazole 400 mg daily, itraconazole 400 mg daily, clarithromycin: No more than 2.5 mg in a 24-hour period.
• Ketoconazole 200 mg daily, itraconazole 200 mg daily, erythromycin: No more than 5 mg in a 24-hour period.
• Cobicistat: No more than 2.5 mg in a 72 hour period.

Alpha-Blockers: In those patients who are stable on alpha-blocker therapy, phosphodiesterase type 5 (PDE5) inhibitors should be initiated at the lowest recommended starting dose. Concomitant treatment should be initiated only if the patient is stable on his alpha-blocker therapy. Stepwise increase in alpha-blocker dose may be associated with further lowering of blood pressure in patients taking a phosphodiesterase (PDE5) inhibitor including vardenafil. In those patients who are stable on alpha-blocker therapy, vardenafil hydrochloride tablets should be initiated at a dose of 5 mg (2.5 mg when used concomitantly with certain CYP3A4 inhibitors). [See Warnings and Precautions (5.6) and Drug Interactions (7.1).]

A time interval between dosing should be considered when vardenafil hydrochloride tablets are prescribed concomitantly with alpha-blocker therapy [see Clinical Pharmacology (12.2)] .

General

Physicians should consider the cardiovascular status of their patients, since there is a degree of cardiac risk associated with sexual activity. Therefore, treatment for erectile dysfunction, including vardenafil hydrochloride tablets, should not be used in men for whom sexual activity is not recommended because of their underlying cardiovascular status.

There are no controlled clinical data on the safety or efficacy of vardenafil in the following patients; and therefore its use is not recommended until further information is available: unstable angina; hypotension (resting systolic blood pressure of <90 mmHg); uncontrolled hypertension (>170/110 mmHg); recent history of stroke, life-threatening arrhythmia, or myocardial infarction (within the last 6 months); severe cardiac failure.

Left Ventricular Outflow Obstruction

Patients with left ventricular outflow obstruction, (for example, aortic stenosis and idiopathic hypertrophic subaortic stenosis) can be sensitive to the action of vasodilators including PDE5 inhibitors.

Blood Pressure Effects

Vardenafil hydrochloride tablets have systemic vasodilatory properties that resulted in transient decreases in supine blood pressure in healthy volunteers (mean maximum decrease of 7 mmHg systolic and 8 mmHg diastolic) [see Clinical Pharmacology (12.2)] . While this normally would be expected to be of little consequence in most patients, prior to prescribing vardenafil hydrochloride tablets, physicians should carefully consider whether their patients with underlying cardiovascular disease could be affected adversely by such vasodilatory effects.

All Vardenafil Studies: Vardenafil hydrochloride 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 vardenafil hydrochloride 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 vardenafil hydrochloride 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

Ophthalmologic: 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  [see Warnings and Precautions (5.4) and Patient Counseling Information (17)] .

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.

Neurologic: Seizure, seizure recurrence and transient global amnesia have been reported postmarketing in temporal association with vardenafil.

Otologic: 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 [see Patient Counseling Information (17)] .

Nitrates: Concomitant use of vardenafil hydrochloride tablets and nitrates and nitric oxide donors is contraindicated. The blood pressure lowering effects of sublingual nitrates (0.4 mg) taken 1 and 4 hours after vardenafil and increases in heart rate when taken at 1, 4 and 8 hours after vardenafil were potentiated by a 20 mg dose of vardenafil hydrochloride tablets in healthy middle-aged subjects. These effects were not observed when vardenafil hydrochloride tablets 20 mg were taken 24 hours before the nitroglycerin (NTG). Potentiation of the hypotensive effects of nitrates for patients with ischemic heart disease has not been evaluated, and concomitant use of vardenafil hydrochloride tablets and nitrates is contraindicated [see Contraindications (4.1) and Clinical Pharmacology (12.2).

Alpha-Blockers: Caution is advised when PDE5 inhibitors are co-administered with alpha-blockers. PDE5 inhibitors, including vardenafil hydrochloride tablets and alpha-adrenergic blocking agents are both vasodilators with blood-pressure-lowering effects. When vasodilators are used in combination, an additive effect on blood pressure may be anticipated. Clinical pharmacology studies have been conducted with co-administration of vardenafil with alfuzosin, terazosin or tamsulosin. [See Dosage and Administration (2.4), Warnings and Precautions (5.6), and Clinical Pharmacology (12.2).]

Antihypertensives: Vardenafil hydrochloride tablets may add to the blood pressure lowering effects of antihypertensive agents. 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.

Alcohol: Vardenafil hydrochloride tablets (20 mg) did not potentiate the hypotensive effects of alcohol during the 4-hour observation period in healthy volunteers when administered with alcohol (0.5 g/kg body weight, approximately 40 mL of absolute alcohol in a 70 kg person). Alcohol and vardenafil plasma levels were not altered when dosed simultaneously.

In vitro studies

Studies in human liver microsomes showed that vardenafil is metabolized primarily by cytochrome P450 (CYP) isoforms 3A4/5, and to a lesser degree by CYP2C9. Therefore, inhibitors of these enzymes are expected to reduce vardenafil clearance [see Dosage and Administration (2.4) and Warnings and Precautions (5.2)] .

In vivo studies

Other Drug Interactions

No pharmacokinetic interactions were observed between vardenafil and the following drugs: glyburide, warfarin, digoxin, an antacid based on magnesium-aluminum hydroxide, and ranitidine. In the warfarin study, vardenafil had no effect on the prothrombin time or other pharmacodynamic parameters.

Cimetidine (400 mg b.i.d.) had no effect on vardenafil bioavailability (AUC) and maximum concentration (C max) of vardenafil when co-administered with 20 mg vardenafil hydrochloride tablets in healthy volunteers.

In vitro studies

Vardenafil and its metabolites had no effect on CYP1A2, 2A6, and 2E1 (Ki >100 micromolar). Weak inhibitory effects toward other isoforms (CYP2C8, 2C9, 2C19, 2D6, 3A4) were found, but Ki values were in excess of plasma concentrations achieved following dosing. The most potent inhibitory activity was observed for vardenafil metabolite M1, which had a Ki of 1.4 micromolar toward CYP3A4, which is about 20 times higher than the M1 C max values after an 80 mg vardenafil dose.

In vitro data suggest that vardenafil has the potential to inhibit P-glycoprotein (P-gp) at therapeutic doses. While concomitant use of vardenafil hydrochloride tablets did not significantly increase plasma concentrations of digoxin, a P-gp substrate, the effect on plasma concentrations of P-gp substrates that are more sensitive than digoxin (e.g. dabigatran) is not known.

In vivo studies

Risk Summary

Vardenafil hydrochloride tablets are not indicated for use in females.

There are no data with the use of vardenafil hydrochloride tablets in pregnant women to inform any drug-associated risks. In animal reproduction studies conducted in pregnant rats and rabbits, no adverse developmental outcomes were observed with oral administration of vardenafil during organogenesis at exposures for unbound vardenafil and its major metabolite at approximately 100 and 29 times, respectively, the maximum recommended human dose (MRHD) of 20 mg based on AUC (see Data).

Data

Animal Data

No evidence of specific potential for teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits that received vardenafil at up to 18 mg/kg/day during organogenesis. This dose is approximately 100 fold (rat) and 29 fold (rabbit) greater than the AUC values for unbound vardenafil and its major metabolite in humans given the MRHD of 20 mg.

In the rat pre-and postnatal development study, the NOAEL (no observed adverse effect level) for maternal toxicity was 8 mg/kg/day. Retarded physical development of pups in the absence of maternal effects was observed following maternal exposure to 1 and 8 mg/kg possibly due to vasodilatation and/or secretion of the drug into milk. The number of living pups born to rats exposed pre- and postnatally was reduced at 60 mg/kg/day. Based on the results of the pre- and postnatal study, the developmental NOAEL is less than 1 mg/kg/day. Based on plasma exposures in the rat developmental toxicity study, 1 mg/kg/day in the pregnant rat is estimated to produce total AUC values for unbound vardenafil and its major metabolite comparable to the human AUC at the MRHD of 20 mg.

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 [see Drug Interactions (7)] .

Effects on Blood Pressure and Heart Rate when Vardenafil Hydrochloride Tablets are 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 vardenafil hydrochloride tablets 20 mg at various times before NTG administration. Vardenafil hydrochloride tablets 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 vardenafil hydrochloride tablets 20 mg were 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 vardenafil hydrochloride tablets 20 mg were 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 [see Contraindications (4.1)] .

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.

Study 1: 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)

Alpha-Blocker		Simultaneous dosing of Vardenafil 5 mg and Alpha-Blocker, Placebo-Subtracted	Dosing of Vardenafil 5 mg and Alpha-Blocker Separated by 6 Hours, Placebo-Subtracted
Terazosin	Standing SBP	-3 (-6.7, 0.1)	-4 (-7.4, -0.5)
5 or 10 mg daily	Supine SBP	-4 (-6.7, -0.5)	-4 (-7.1, -0.7)
Tamsulosin	Standing SBP	-6 (-9.9, -2.1)	-4 (-8.3, -0.5)
0.4 mg daily	Supine SBP	-4 (-7, -0.8)	-5 (-7.9, -1.7)

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)

Study 2: 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 6­ hour 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)

	Vardenafil 10 mg Placebo-subtracted	Vardenafil 20 mg Placebo-subtracted
Standing SBP	-4 (-6.8, -0.3)	-4 (-6.8, -1.4)
Supine SBP	-5 (-8.2, -0.8)	-4 (-6.3, -1.8)

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)

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 T max 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 T max than when dosing was administered to separate T max 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 T max administration of tamsulosin. There were no cases of syncope.

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 (0.4 mg) in healthy volunteers

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 vardenafil hydrochloride tablets (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 vardenafil hydrochloride tablets (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 (QT c) 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 vardenafil hydrochloride tablets compared to placebo was 5 beats/minute and with an 80 mg dose of vardenafil hydrochloride tablets the mean increase was 6 beats/minute.

Therapeutic and supratherapeutic doses of vardenafil and the active control moxifloxacin produced similar increases in QT c interval. This study, however, was not designed to make direct statistical comparisons between the drug or the dose levels. The clinical impact of these QT c changes is unknown [see Warnings and Precautions (5)] .

In a separate postmarketing study of 44 healthy volunteers, single doses of 10 mg vardenafil hydrochloride tablets 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 vardenafil hydrochloride tablets 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 [see Warnings and Precautions (5.7)] .

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 vardenafil hydrochloride tablets did not alter the total treadmill exercise time compared to placebo (10 mg vardenafil hydrochloride tablets vs. placebo: 433±109 and 426±105 seconds, respectively; 20 mg vardenafil hydrochloride tablets vs. placebo: 414±114 and 411±124 seconds, respectively). The total time to angina was not altered by vardenafil hydrochloride tablets when compared to placebo (10 mg vardenafil hydrochloride tablets vs. placebo: 291±123 and 292±110 seconds; 20 mg vardenafil hydrochloride tablets 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 vardenafil hydrochloride tablet groups (10 mg vardenafil hydrochloride tablets vs. placebo: 380±108 and 334±108 seconds; 20 mg vardenafil hydrochloride tablets 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, vardenafil hydrochloride tablets 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.

Absorption

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 Vardenafil Hydrochloride Tablets 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 C max by 18%-50%.

Distribution

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.

Metabolism

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.

Excretion

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

Carcinogenesis

Vardenafil was not carcinogenic in rats and mice when administered daily for 24 months. In these studies systemic drug exposures (AUCs) for unbound (free) vardenafil and its major metabolite were approximately 400- and 170-fold for male and female rats, respectively, and 21- and 37-fold for male and female mice, respectively, the exposures observed in human males given the Maximum Recommended Human Dose (MRHD) of 20 mg.

Mutagenesis

Vardenafil was not mutagenic as assessed in either the in vitro bacterial Ames assay or the forward mutation assay in Chinese hamster V 79 cells. Vardenafil was not clastogenic as assessed in either the in vitro chromosomal aberration test or the in vivo mouse micronucleus test.

Impairment of Fertility

Vardenafil did not impair fertility in male and female rats administered doses up to 100 mg/kg/day for 28 days prior to mating in male, and for 14 days prior to mating and through day 7 of gestation in females. In a corresponding 1-month rat toxicity study, this dose produced an AUC value for unbound vardenafil 200 fold greater than AUC in humans at the MRHD of 20 mg.