What You Should Know About Avanafil Side Effects

Every medication has potential side effects, and Avanafil — sold under the brand name Stendra — is no exception. The good news is that most people tolerate Avanafil well, and the most common side effects tend to be mild and temporary.

Still, it's important to know what to watch for, what's normal, and what warrants a call to your doctor. This guide breaks down the full picture based on FDA labeling and clinical trial data.

What Is Avanafil?

Avanafil is a phosphodiesterase type 5 (PDE5) inhibitor prescribed for erectile dysfunction (ED). It works by increasing blood flow to the penis during sexual stimulation. Compared to other PDE5 inhibitors like Sildenafil (Viagra) and Tadalafil (Cialis), Avanafil is known for its relatively fast onset — it can start working in as little as 15 to 30 minutes. For a deeper dive, see our guide on what Avanafil is and how it's used.

Common Side Effects

In clinical trials, the following side effects were reported most frequently. These are generally mild and often improve as your body adjusts to the medication:

• Headache — The most common side effect, affecting 10 to 15% of users. Usually mild and resolves within a few hours.
• Flushing — A warm feeling or redness in the face, neck, or chest. This happens because Avanafil dilates blood vessels.
• Nasal congestion — A stuffy nose is common with all PDE5 inhibitors.
• Nasopharyngitis — Cold-like symptoms including sore throat and runny nose.
• Back pain — Some users report mild back discomfort, usually temporary.
• Upper respiratory infection — Mild URI symptoms have been reported in clinical trials.
• Dizziness — Particularly when standing up quickly, due to the blood pressure-lowering effect of the medication.

Most of these side effects are dose-related — they're more common at the 200 mg dose than at 50 mg or 100 mg. If side effects bother you, your doctor may lower your dose.

Serious Side Effects

While rare, some side effects of Avanafil are serious and require immediate medical attention:

Priapism

An erection lasting more than 4 hours is a medical emergency called priapism. If not treated promptly, priapism can cause permanent damage to the penis. Go to the emergency room immediately if this happens. Men with sickle cell anemia, multiple myeloma, or leukemia may be at higher risk.

Sudden Vision Loss

In rare cases, PDE5 inhibitors have been linked to non-arteritic anterior ischemic optic neuropathy (NAION) — a sudden loss of vision in one or both eyes. Stop taking Avanafil and call your doctor right away if you experience sudden vision changes. Risk factors include age over 50, diabetes, heart disease, high blood pressure, high cholesterol, and smoking.

Sudden Hearing Loss

Some patients have reported sudden hearing loss or ringing in the ears (tinnitus) while taking PDE5 inhibitors. If this occurs, stop taking Avanafil and seek medical care immediately.

Severe Hypotension

Avanafil lowers blood pressure. When combined with nitrates (like Nitroglycerin) or alpha-blockers, the drop can be dangerously severe — causing fainting, heart attack, or stroke. This is why Avanafil is contraindicated with all forms of nitrates. Read more about Avanafil drug interactions.

Cardiovascular Events

Men with pre-existing heart conditions should use Avanafil with caution. Sexual activity itself puts extra demand on the heart, and the blood pressure-lowering effects of Avanafil can add to that burden. Talk to your doctor about whether sexual activity is safe for you.

Who Needs Extra Caution

Certain groups should be especially careful with Avanafil or may need dose adjustments:

• Adults over 65 — No automatic dose adjustment is needed, but older adults may be more sensitive to side effects like dizziness and blood pressure changes.
• People with liver problems — Mild to moderate liver impairment is generally fine, but patients with severe hepatic impairment (Child-Pugh C) should not use Avanafil.
• People with kidney problems — Those with severe renal impairment (CrCl below 30 mL/min) should not take Avanafil. Mild to moderate kidney issues don't require dose changes.
• People on blood pressure medications — Avanafil can add to the blood pressure-lowering effects of antihypertensives. Your doctor may need to monitor you more closely.
• People taking moderate CYP3A4 inhibitors — Medications like Diltiazem, Verapamil, or Erythromycin limit how your body processes Avanafil. If you take one of these, your maximum Avanafil dose is 50 mg per day.

How to Manage Common Side Effects

If you experience mild side effects, these strategies can help:

• For headaches: Over-the-counter pain relievers like Acetaminophen (Tylenol) or Ibuprofen (Advil) usually help. Stay hydrated.
• For flushing: This typically passes on its own within 30 to 60 minutes. Avoid alcohol, which can make flushing worse.
• For nasal congestion: A saline nasal spray can provide relief. Avoid decongestants containing Pseudoephedrine if you have high blood pressure.
• For dizziness: Stand up slowly, especially from a sitting or lying position. Avoid alcohol. Make sure you're well-hydrated.
• For back pain: Usually mild and resolves within 24 to 48 hours. Over-the-counter pain relievers can help.

If any common side effect persists for more than a few days or gets worse over time, let your doctor know. They may adjust your dose or suggest a different medication.

Talk to Your Doctor About Dose Adjustment

The recommended starting dose of Avanafil is 100 mg. If you experience side effects, your doctor can lower the dose to 50 mg. Conversely, if 100 mg isn't effective enough, they may increase it to 200 mg — but be aware that higher doses come with a higher chance of side effects.

When to Call Your Doctor

Contact your healthcare provider if you experience:

• Side effects that don't go away or get worse over time
• An erection lasting longer than 4 hours (go to the ER)
• Sudden changes in vision or hearing
• Chest pain during or after sexual activity
• Fainting or severe dizziness
• An allergic reaction (rash, hives, swelling, difficulty breathing)

Don't tough it out. These situations need medical attention.

Final Thoughts

Avanafil is generally well-tolerated, and most side effects are mild and short-lived. The key is knowing what's normal (a headache that goes away in a couple of hours) versus what's not (an erection that won't go down, or sudden vision loss). If you're considering Avanafil, have an open conversation with your doctor about your health history and any other medications you take.

For help finding Avanafil at a pharmacy near you, visit Medfinder. And if you're curious about how Avanafil compares to other ED medications, check out our guide on alternatives to Avanafil.