Phenoxybenzamine and Stendra

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Talk to your doctor before using avanafil together with phenoxybenzamine. Combining these medications can lower your blood pressure and increase the risk of dizziness, lightheadedness, fainting, flushing, headache, and nasal congestion. These side effects may also occur with either medication alone and are most likely to be seen at the beginning of treatment, following a dose increase, or when treatment is restarted after an interruption. Let your doctor know if you develop these symptoms and they do not go away after a few days or they become troublesome. Avoid driving or operating hazardous machinery until you know how these medications affect you, and use caution when getting up from a sitting or lying position. In general, your blood pressure should be stable and you should be on a steady dose of one medication before you begin the other. You may need a dose adjustment or your blood pressure checked more often if you take both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

ADJUST DOSE: Avanafil may potentiate the hypotensive effect of alpha blockers, resulting in symptomatic hypotension in some patients. Avanafil inhibits phosphodiesterase-5-mediated degradation of cyclic guanosine monophosphate (cGMP), which in vascular smooth muscles can cause peripheral vasodilation that may be additive with that induced by alpha blockers. In 24 healthy male subjects taking doxazosin 8 mg daily for 11 days, administration of a single 200 mg dose of avanafil resulted in potentially clinically significant augmentation of the blood pressure lowering effect of doxazosin in some subjects. Specifically, seven subjects given avanafil had either a standing systolic blood pressure (SBP) or diastolic blood pressure (DBP) of less than 85 mmHg or 45 mmHg, respectively, and/or a decrease from baseline of greater than 30 mmHg for standing SBP or 20 mmHg for standing DBP, compared to one such subject when given placebo. In another cohort of 24 healthy male subjects given tamsulosin 0.4 mg daily for 11 days, 5 subjects experienced potentially clinically significant absolute values and/or changes from baseline in standing SBP or DBP after administration of a single 200 mg dose of avanafil, whereas only one subject did so after receiving placebo. The placebo-subtracted mean maximum decreases from baseline in standing and supine SBP with avanafil 200 mg was -2.5 and -6.0, respectively, in the doxazosin cohort and -3.6 and -3.1, respectively, in the tamsulosin cohort. There were no severe adverse events related to hypotension and no cases of syncope reported in study subjects.

MANAGEMENT: Caution is advised if avanafil is used in combination with alpha blockers. Patients who demonstrate hemodynamic instability on alpha blocker therapy alone are at increased risk of symptomatic hypotension with concomitant use of avanafil. Therefore, patients should be stable on alpha blocker therapy prior to initiating avanafil, and avanafil should be initiated at the lowest recommended dosage of 50 mg. In those patients already on an optimized dosage of avanafil, alpha blocker therapy should be initiated at the lowest dosage. The safety of avanafil in combination with alpha blockers may also be affected by other variables such as intravascular volume depletion and use of other antihypertensive medications.

Phenoxybenzamine

Generic Name: phenoxybenzamine

Brand name: Dibenzyline

Synonyms: n.a.

What is Phenoxybenzamine?

Stendra

Generic Name: avanafil

Brand name: Stendra

Synonyms: n.a.

What is Stendra?