VARDENAFIL HYDROCHLORIDE (Page 4 of 7)

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Risk Summary

Vardenafil hydrochloride is not indicated for use in females.

There are no data with the use of vardenafil hydrochloride 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 maximum recommended human dose 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.

8.2 Lactation

Risk Summary
Vardenafil hydrochloride is not indicated for use in females.

There is no information on the presence of vardenafil and its major metabolite in human milk, the effects on the breastfed infant, or the effects on milk production. Vardenafil is present in rat milk of lactating rats (see Data).

Data Vardenafil was secreted into the milk of lactating rats at concentrations approximately 10-fold greater than found in the plasma. Following a single oral dose of 3 mg/kg, 3.3% of the administered dose was excreted into the milk within 24 hours.

8.4 Pediatric Use

Vardenafil hydrochloride is not indicated for use in pediatric patients. Safety and efficacy have not been established in this population.

8.5 Geriatric Use

Elderly males 65 years of age and older have higher vardenafil plasma concentrations than younger males (18 to 45 years), mean Cmax and AUC were 34% and 52% higher, respectively. Phase 3 clinical trials included more than 834 elderly patients, and no differences in safety or effectiveness of vardenafil hydrochloride 5, 10, or 20 mg were noted when these elderly patients were compared to younger patients. However, due to increased vardenafil concentrations in the elderly, a starting dose of 5 mg vardenafil hydrochloride should be considered in patients ≥65 years of age [see Clinical Pharmacology (12.3)].

8.6 Hepatic Impairment

Dosage adjustment is necessary in patients with moderate hepatic impairment.

Do not use vardenafil hydrochloride in patients with severe hepatic impairment (Child-Pugh C). Vardenafil has not been evaluated in this patient population.

A starting dose of 5 mg is recommended in patients with moderate hepatic impairment (Child-Pugh B) and the maximum dose should not exceed 10 mg. In volunteers with moderate hepatic impairment, the Cmax and AUC following a 10 mg vardenafil dose were increased by 130% and 160%, respectively, compared to healthy control subjects [see Warnings and Precautions (5.8) and Dosage and Administration (2.3)].

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. No dosage adjustment is necessary in patients with mild hepatic impairment.

8.7 Renal Impairment

Do not use vardenafil hydrochloride in patients on renal dialysis as vardenafil has not been evaluated in such patients.

No dosage adjustment is necessary in patients with creatinine clearance (CLcr) of 30 to 80 mL/min. In male volunteers with CLcr = 50 to 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 to 50 mL/min or CLcr<30 mL/min, the AUC of vardenafil was 20 to 30% higher compared to that observed in a control group with CLcr>80 mL/min [see Dosage and Administration (2.3) and Warnings and Precautions (5.9)].

10 OVERDOSAGE

The maximum dose of vardenafil hydrochloride for which human data are available is a single 120 mg dose administered to healthy male volunteers. The majority of these subjects experienced reversible back pain/myalgia and/or “abnormal vision.” Single doses up to 80 mg vardenafil and multiple doses up to 40 mg vardenafil administered once daily over 4 weeks were tolerated without producing serious adverse side effects.

When 40 mg of vardenafil was administered twice daily, cases of severe back pain were observed. No muscle or neurological toxicity was identified.

In cases of overdose, standard supportive measures should be taken as required. Renal dialysis is not expected to accelerate clearance as vardenafil is highly bound to plasma proteins and not significantly eliminated in the urine.

11 DESCRIPTION

Vardenafil hydrochloride tablets are administered orally for the treatment of erectile dysfunction. This monohydrochloride salt of vardenafil is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5).

Vardenafil hydrochloride is designated chemically as piperazine, 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1-f ][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-4-ethyl-, monohydrochloride and has the following structural formula:

Structure
(click image for full-size original)

Vardenafil hydrochloride is a white or slightly brown or yellow powder with a molecular weight of 579.11. It is slightly soluble in water, freely soluble in anhydrous ethanol. Practically insoluble in heptane.

Vardenafil hydrochloride is available as film-coated tablets for oral administration, containing 2.5 mg, 5 mg, 10 mg and 20 mg of vardenafil. The inactive ingredients are microcrystalline cellulose, hydroxypropyl cellulose, crospovidone, talc, colloidal silicon dioxide and magnesium stearate. The colorants include hypromellose, titanium dioxide, polyethylene glycol 6000, iron oxide yellow, iron oxide red, FD&C Yellow No. 5 Tartrazine Aluminum Lake and FD&C Yellow No. 6 Sunset Yellow FCF Aluminum Lake.

12 CLINICAL PHARMACOLOGY

12.1 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).

12.2 Pharmacodynamics

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 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 vardenafil hydrochloride 20 mg at various times before NTG administration. Vardenafil hydrochloride 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 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 vardenafil hydrochloride 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

Figure 1
(click image for full-size original)

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 5 or 10 mg dailyStanding SBP-3 (-6.7, 0.1)-4 (-7.4, -0.5)
Supine SBP-4 (-6.7, -0.5)-4 (-7.1, -0.7)
Tamsulosin 0.4 mg dailyStanding SBP-6 (-9.9, -2.1)-4 (-8.3, -0.5)
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 2
(click image for full-size original)

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)

Figure 3
(click image for full-size original)

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)

Figure 4
(click image for full-size original)

Study 3: 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, 3­-period 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)

Vardenafil 5 mg Placebo-subtracted Vardenafil 10 mg Placebo-subtracted
Standing SBP-2 (-5.8, 1.2)-5 (-8.8, -1.6)
Supine SBP-1 (-4.1, 2.1)-6 (-9.4, -2.8)

One patient experienced decrease 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 alfuzosin 10 mg in BPH patients (Study 3)

Figure 5
(click image for full-size original)

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 to 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

Alpha-Blocker Dosing of Vardenafil and Alpha-Blocker Separated by 6 Hours Simultaneous Dosing of Vardenafil and Alpha-Blocker
Vardenafil 10 mg Placebo- Subtracted Vardenafil 20 mg Placebo- Subtracted Vardenafil 10 mg Placebo- Subtracted Vardenafil 20 mg Placebo- Subtracted
Terazosin 10 mg dailyStanding SBP-7 (-10, -3)-11(-14, -7)-23 (-31, 16)a -14 (-33, 11)a
Supine SBP-5 (-8, -2)-7 (-11, -4)-7 (-25, 19)a -7 (-31, 22)a
Tamsulosin 0.4 mg dailyStanding SBP-4 (-8, -1)-8 (-11, -4)-8 (-14, -2)-8 (-14, -1)
Supine SBP-4 (-8, 0)-7 (-11, -3)-5 (-9, -2)-3 (-7, 0)

a) Due to the sample size, confidence intervals may not be an accurate measure for these data. These values represent the range for the difference.

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 6
(click image for full-size original)

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

Figure 7
(click image for full-size original)

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 to 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 (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 (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 vardenafil hydrochloride compared to placebo was 5beats/minute and with an 80 mg dose of vardenafil hydrochloride 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

Drug/Dose QT Uncorrected (msec) Fridericia QT Correction (msec) Individual QT Correction (msec)
Vardenafil 10 mg -2(-4, 0)8(6, 9)4(3, 6)
Vardenafil 80 mg -2(-4, 0)10(8, 11)6(4, 7)
Moxifloxacin a 400 mg3(1, 5)8(6, 9)7(5, 8)

a) Active control (drug known to prolong QT)

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 [see Warnings and Precautions (5)].

In a separate postmarketing study of 44 healthy volunteers, single doses of 10 mg vardenafil hydrochloride 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 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 to 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 did not alter the total treadmill exercise time compared to placebo (10 mg vardenafil hydrochloride vs. placebo: 433±109 and 426±105 seconds, respectively; 20 mg vardenafil hydrochloride vs. placebo: 414±114 and 411±124 seconds, respectively). The total time to angina was not altered by vardenafil hydrochloride when compared to placebo (10 mg vardenafil hydrochloride vs. placebo: 291±123 and 292±110 seconds; 20 mg vardenafil hydrochloride 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 groups (10 mg vardenafil hydrochloride vs. placebo: 380±108 and 334±108 seconds; 20 mg vardenafil hydrochloride 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 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.

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