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 BRAND NAMES
 MECHANISM OF ACTION
The physiological mechanism responsible for erection of the penis involves the release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. Nitric oxide then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood.
Phosphodiesterase type 5 (PDE5) is the enzyme responsible for degradation of cGMP
Avanafil, is an inhibitor of phosphodiesterase type 5 (PDE5). When sexual stimulation causes local release of NO, inhibition of PDE5 by Avanafil causes increased levels of cGMP in the corpus cavernosum, resulting in smooth muscle relaxation and inflow of blood to the corpus cavernosum. Avanafil at recommended doses has no effect in the absence of sexual stimulation.
- Avanafil is indicated in adult men with erectile dysfunction, which is the inability to achieve or maintain a penile erection sufficient for satisfactory sexual performance.
The recommended dose of Avanafil is 100 mg taken as needed about 30 minutes before sexual activity. The dose may be increased to a maximum of 200 mg or decreased to 50 mg depending on the effectiveness and side effects.
The recommended starting dose of Avanafil in patients on stable alpha-blocker therapy e.g. Hytrin® (terazosin HCl), Flomax® (tamsulosin HCl), Cardura® (doxazosin mesylate), Minipress® (prazosin HCl) or Uroxatral® (alfuzosin HCl) is 50 mg.
The maximum recommended dosing frequency is one tablet per day.
Avanafil may be taken with or without food
- Avanafil potentiate the hypotensive effects of nitrates and its administration in patients who use nitric oxide donors or nitrates in any form is therefore contraindicated.
- In men for whom sexual activity is inadvisable (e.g.Patients with severe cardiovascular disorders such as unstable angina or severe cardiac failure)
- History of known serious hypersensitivity reaction to Avanafil
- Concomitant use with strong CYP3A4 inhibitors (including ketoconazole, ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir and telithromycin)
 WARNINGS AND PRECAUTIONS
- Avanafil has systemic vasodilatory properties and may augment the blood pressure lowering effect of anti-hypertensive medications.
- Use of Avanafil with substantial amounts of alcohol (greater than 3 units) may lead to hypotension
- Seek emergency treatment for prolonged erections greater than 4 hours and priapism
- Caution is advised when Avanafil is used as a treatment for Erectile dysfunction in men taking alpha blockers because of the risk of hypotension. the recommended starting dose of Avanafil in patients on stable alpha-blocker therapy is 50 mg.
- Patients should seek medical attention and stop taking Avanafil in case of sudden loss of vision in one or both eyes ( increased risk of non-arteritic anterior ischemic optic neuropathy)
- Patients should seek medical attention and stop taking Avanafil in case of sudden decrease or loss in hearing
- CYP3A4 inhibitors:
- Potent CYP3A4 inhibitors: Concomitant use with potent CYP3A4 inhibitors is contraindicated e.g. Ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, ketoconazole, telithromycin (Potent CYP3A4 inhibitors increase Avanafil plasma levels).
- Moderate CYP3A4 inhibitors: Patients taking concomitant moderate CYP3A4 inhibitors (including erythromycin, amprenavir, aprepitant, diltiazem, fluconazole, fosamprenavir, and verapamil), the maximum recommended dose of Avanafil is 50 mg
- Avanafil can potentiate the hypotensive effect of nitrates, alpha-blockers, antihypertensives, and alcohol
 PREGNANCY AND LACTATION
Pregnancy Category C (US). Avanafil is not indicated for use in women
 SIDE EFFECTS
Most common adverse reactions (greater than or equal to 2%) include headache, flushing, nasal congestion, nasopharyngitis, and back pain.
 RELATED LINKS
- Sildenafil (Erectile Dysfunction) (Viagra)
- Vardenafil (Levitra)
- Tadalafil (Cialis)