New York—Concomitant use of vardenafil (Levitra) for the treatment of erectile dysfunction and tamsulosin (Flomax) for chronic therapy of benign prostatic hyperplasia (BPH) does not induce clinically significant reductions in standing blood pressure (BP), said investigators at the American Society of Hypertension meeting.
“We found small asymptomatic reductions relative to placebo in supine and standing blood pressure in patients with BPH given vardenafil, 10 or 20 mg, simultaneously with tamsulosin,” said William B. White, MD, chief, section of hypertension and pharmacology, University of Connecticut, Farmington.
When phsophodiesterase-5 inhibitors (PDE-5) such as vardenafil are coadministered with alpha blockers, a pharmacodynamic interaction is possible that may result in clinically significant reductions in BP.
Differences exist in the approved labeling for PDE-5 inhibitors, such that sildenafil (Viagra) has no significant restrictions on its use with alpha blockers, except waiting for 4 hours after the administration of doxazosin. Tadalafil(Cialis), a 24-hour PDE-5 inhibitor, has no restriction for use with tamsulosin but has a restriction with other alpha blockers, such as terazosin and doxazosin. According to the current package insert for vardenafil, this agent is contraindicated for use with any alpha blocker. Tamsulosin is currently the most frequently prescribed alpha blocker for men.
This study included 23 normotensive men aged 40 to 80 years who were on stable tamsulosin therapy (0.4 or 0.8 mg/d) for BPH. They received vardenafil, 10 mg/d, or placebo in stage 1, and then vardenafil, 20 mg/d, or placebo in stage 2 of the study.
Concomitant use of vardenafil and tamsulosin produced small clinically insignificant changes in mean maximal standing BP and heart rate. “There was no dose response [in BP reduction] with vardenafil, which is typical of PDE-5 inhibitors as a class,” Dr White said.
Standing BP dropped by 3.5/0.8 mm Hg with 10 mg of vardenafil compared with placebo, and by 4.1/3.3 mm Hg with 20 mg of vardenafil compared with placebo. Heart rate increased by 2 to 3 beat per minute with either dose of vardenafil.
Individual responses were also examined “because the FDA is very worried about outliers…the chance that an individual will bottom out,” Dr White said. “Individual responses were virtually the same on vardenafil and placebo.”
Two placebo recipients and 1 patient treated with 10 mg of vardenafil had a drop in standing diastolic BP of at least 20 mm Hg, and 1 patient receiving 20 mg of vardenafil had a drop in standing systolic BP of >30 mm Hg.
The individual responses were not statistically different between 10 or 20 mg of vardenafil and placebo. “Nobody had an SBP [systolic blood pressure] that dropped below 85 mm Hg on standing,” said Dr White.
With respect to changes in standing BP, “vardenafil looks the same in combination with tamsulosin as the other PDE-5 inhibitors,” he said.