What is Avanafil?
Avanafil is the generic name for the prescription drug that is also sold under the brand name Stendra. It belongs to a class of drugs called phosphodiesterase-5 (PDE5) inhibitors, which are primarily used to treat erectile dysfunction (ED). Avanafil works similarly to other PDE5 inhibitors, but it is known for its rapid onset of action, with effects sometimes beginning as quickly as 15 minutes after taking a dose. As with any generic and brand-name drug pairing, the generic avanafil contains the exact same active ingredient as Stendra and has the same effects and risks, but is often available at a lower cost. The availability of generic options can make treatment more accessible for many patients.
How Avanafil Works
The mechanism of action for avanafil, and other PDE5 inhibitors, is centered on regulating blood flow to the penis. To achieve an erection, sexual stimulation causes the release of nitric oxide (NO) in the penis's erectile tissue, called the corpus cavernosum. This release of NO triggers an enzyme that increases the production of cyclic guanosine monophosphate (cGMP), which relaxes the smooth muscles in the arteries of the penis and allows more blood to flow in.
Here's how avanafil specifically affects this process:
- Targeting PDE5: The PDE5 enzyme is responsible for breaking down cGMP in the penis, which causes the smooth muscles to contract and blood flow to decrease.
- Inhibiting Breakdown: Avanafil inhibits the action of the PDE5 enzyme, preventing the rapid breakdown of cGMP.
- Sustaining Blood Flow: By keeping cGMP levels elevated, avanafil allows the smooth muscles to remain relaxed for a longer period, thus sustaining increased blood flow and maintaining an erection.
- Requires Sexual Stimulation: It is important to note that avanafil does not cause an erection on its own. Sexual stimulation is required to initiate the natural release of nitric oxide and for the medication to be effective.
Avanafil Compared to Other ED Treatments
Avanafil is one of several PDE5 inhibitors used for treating erectile dysfunction. Others include sildenafil (Viagra) and tadalafil (Cialis). Avanafil is distinguished by its faster onset and high selectivity for the PDE5 enzyme, which may lead to a lower incidence of certain side effects.
| Feature | Avanafil (Stendra) | Sildenafil (Viagra) | Tadalafil (Cialis) |
|---|---|---|---|
| Onset of Action | ~15-30 minutes | ~30-60 minutes | ~30-120 minutes |
| Duration of Effect | Up to 6 hours | ~4 hours, up to 12 hours | Up to 36 hours |
| Selectivity | Highly selective for PDE5 over PDE6 | Less selective for PDE5 over PDE6 | More selective for PDE5 over PDE11 |
| Common Side Effects | Headache, flushing, congestion | Headache, flushing, vision changes | Headache, muscle aches, back pain |
| Food Impact | Minimal impact on absorption | Food, especially fatty meals, may delay effect | Minimal impact on absorption |
Potential Side Effects and Precautions
While avanafil is generally well-tolerated, it is important to be aware of potential side effects and drug interactions. Common side effects often resolve on their own.
Common Side Effects:
- Headache
- Flushing (redness of the face, neck, or chest)
- Nasal congestion
- Back pain
- Indigestion
Rare but Serious Side Effects:
- Sudden Vision Loss: A rare but serious event, sometimes permanent, has occurred with PDE5 inhibitors.
- Sudden Hearing Loss: May be accompanied by dizziness or ringing in the ears.
- Priapism: A prolonged, painful erection lasting more than 4 hours is a medical emergency.
Important Precautions and Contraindications:
- Nitrates: Avanafil is contraindicated for patients using any form of organic nitrate (e.g., nitroglycerin) due to the risk of a dangerous drop in blood pressure.
- Riociguat: It should not be used by patients taking guanylate cyclase stimulators like riociguat.
- CYP3A4 Inhibitors: Dosage adjustments or avoidance is necessary when taking medications that inhibit the CYP3A4 enzyme, such as certain antifungals and HIV treatments.
- Alpha-Blockers: Patients on stable alpha-blocker therapy should start with a lower dose of avanafil.
- Underlying Medical Conditions: Use caution with cardiovascular disease, severe kidney or liver impairment, and certain eye conditions.
Conclusion
Avanafil is the generic name for the popular erectile dysfunction medication Stendra. As a highly selective and fast-acting PDE5 inhibitor, it provides a valuable treatment option for men with ED. While it shares a similar mechanism with other ED medications, its speed and selectivity offer potential benefits for some individuals. It is crucial to use avanafil only under the guidance of a healthcare professional, who can determine the correct dosage and ensure it is safe to use given your medical history and other medications. For comprehensive information on prescribing, safety, and administration, consult the Avanafil Prescribing Information from Drugs.com, a reliable source for drug information.
