Avanafil is a new phosphodiesterase-5 inhibitor that is faster acting and more selective than other drugs belonging to the same class. Chemically, it is a derivative of pyrimidine and is only available as the S-enantiomer. Avanafil acts by inhibiting a specific phosphodiesterase type 5 enzyme which is found in various body tissues, but primarily in the corpus cavernosum penis, as well as the retina. The advantage of avanafil is that it has a very fast onset of action compared with other PDE5 inhibitors. It is absorbed quickly, reaching a maximum concentration in about 30–45 minutes. About two-thirds of the participants were able to engage in sexual activity within 15 minutes.
Mechanism of action of Avanafil
Avanafil is a selective phosphodiesterase 5 (PDE5) enzyme inhibitor used for the treatment of erectile dysfunction caused by diabetes, age-induced oxidative stress or other complications. Avanafil inhibits the cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernosum located around the penis. Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and corpus cavernosal smooth muscle. This response is mediated by the release of nitric oxide (NO) from nerve terminals and endothelial cells, which stimulates the synthesis of cGMP in smooth muscle cells. Cyclic GMP causes smooth muscle relaxation and increased blood flows into the corpus cavernosum. The inhibition of phosphodiesterase type 5 (PDE5) by avanafil enhances erectile function by increasing the amount of cGMP.
Indications of Avanafil
- Erectile Dysfunction
- Premature ejaculation
- Persistent or recurrent ejaculation with minimal sexual stimulation before, on, or shortly after penetration and before the patient wishes; and
- Marked personal distress or interpersonal difficulty as a consequence of PE; and
- Poor control over ejaculation;
- A history of premature ejaculation in the majority of intercourse attempts over the prior 6 months.
- Very short sexual intercourse
- Sexual erectile dysfunction
- Inability to sustain a satisfactory erection to complete intercourse
- Treatment of erectile dysfunction in males.
Contra-Indications of Avanafil
- Multiple myelomas
- Leukemia
- Sickle cell anemia
- increased risk of bleeding due to a clotting disorder
- Pigmentary retinopathy
- Hearing loss
- Severe uncontrolled high blood pressure
- Heart Attack
- Unpredictable severe constricting chest Pain
- Narrowing of the aortic heart valve
- hypertrophic cardiomyopathy
- prolonged QT interval on EKG
- Life-threatening irregular heart rhythm
- Chronic heart failure
- Heart attack (within the last 6 months) or
- Hypertension (high blood pressure), uncontrolled or
- Retinal disorders (eye problem) or
- Retinitis pigmentosa (an inherited eye disorder) or
- Stroke (within the last 6 months)
- Bleeding disorders or
- Stomach ulcers
- Leukemia (blood-related cancer) or
- Multiple myeloma (bblood-related cancer) or
- Sickle-cell anemia (blood disorder)
Dosages of Avanafil
Strengths: 50 mg; 100 mg; 200 mg
Erectile Dysfunction
- Initial dose: 100 mg orally as needed approximately 30 minutes before sexual activity.
- Maintenance dose: 50 to 200 mg orally as needed 30 minutes before sexual activity.
- Maximum dose: 200 mg orally once a day
- Initiate treatment at lowest dose, 50 mg PO once daily, approximately 30 minutes before sexual activity. Monitor for dose tolerance, due to potential additive effect on blood pressure. Patients should be stable on alpha-blocker therapy prior to initiating ED treatment.
All Currently Available PDE5 Inhibitors in the United States
| Avanafil | Sildenafil | Vardenafil | Tadalafil | |
|---|---|---|---|---|
| Onset of action | 15-30 minutes | 30-60 minutes | 30-60 minutes | 60-120 minutes |
| Plasma half-life | 3 hours | 4 hours | 4 hours | 17.5 hours |
| Duration of action | Up to 6 hours | Up to 12 hours | Up to 10 hours | Up to 36 hours |
| Effect of food intake | Not affected | High-fat meals decrease efficacy | High-fat meals decrease efficacy | Not affected |
| Unique side effects | Vision abnormalities (PDE6) | Vision abnormalities (PDE6) | Back pain, myalgias |
Side Effects of Avanafil
The most common
- nausea, vomiting, loss of appetite;
- anxiety, sleep problems (insomnia);
- dry mouth, unusual taste;
- little or no urinating;
- constipation;
- vision changes;
- breast swelling (in men or women); or
- decreased sex drive, impotence, or difficulty having an orgasm.
- blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
- restless muscle movements in your eyes, tongue, jaw, or neck;
- a light-headed feeling, like you might pass out;
- seizure (convulsions);
- new or worsening chest pain, pounding heartbeats or fluttering in your chest;
- sudden numbness or weakness, problems with vision, speech, or balance;
- fever, sore throat, easy bruising, unusual bleeding;
- painful or difficult urination;
Common
- Abdominal or stomach pain
- agitation
- blurred vision
- burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings
- change in consciousness
- changes in patterns and rhythms of speech
- chest pain or discomfort
- cold sweats
- confusion
Rare
- Abdominal or stomach pain
- agitation or irritability
- blurred vision
- change in urination
- chest pain or discomfort
- confusion about identity, place, and time
- convulsions
- cool, pale skin
- dizziness, faintness, or lightheadedness when getting up suddenly from a lying or
- Anxiety
- change in vision
- seizures
- weight loss
- chest pain or tightness
- confusion
- cough
- Agitation
- arm, back, or jaw pain
- blurred vision
- chest pain or discomfort
- convulsions
- hallucinations
- headache
- irritability
- muscle pain or cramps
- pale or yellowed skin, dark colored urine, fever, confusion or weakness;
- sore throat, and headache with a severe blistering, peeling, and red skin rash;
- swelling, rapid weight gain, feeling short of breath (even with mild exertion); or
- increased thirst, loss of appetite, urinating less than usual or not at all.
Drug Interactions of Avanafil
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Amyl Nitrite
- Erythrityl Tetranitrate
- Isosorbide Dinitrate
- Isosorbide Mononitrate
- Itraconazole
- Nitroglycerin
- Pentaerythritol Tetranitrate
- Propatyl Nitrate
- Riociguat
- Atazanavir
- Boceprevir
- Clarithromycin
- Cobicistatc
- Darunavir
- Efavirenz
- Etravirine
- Indinavir
- Ketoconazole
- Lopinavir
- Nefazodone
- Nelfinavir
- Netupitant
- Nevirapine
- Posaconazole
- Ritonavir
- Saquinavir
- Telaprevir
- Telithromycin
- Voriconazole
- Doxazosin
- Erythromycin
- Tamsulosin
Other medical abnormality
Other medical abnormality, if that is present, use the avanafil with consulting with a doctor
- Abnormal penis, including curved penis and birth defects of the penis—Chance of problems occurring may be increased and this medicine should be used with caution in these patients.
- Age greater than 50 years or
- Coronary artery disease or
- Crowded disc or low cup to disc ratio in the eye (an eye disorder) or
- Diabetes or
- Heart disease or
- Hyperlipidemia (high fats in the blood) or
- Hypertension (high blood pressure) or
- Non-arteritic anterior ischemic optic neuropathy or NAION (serious eye condition), history of or
- Smoking—May increase the chance for a serious side effect in the eye called NAION.
- Angina (severe chest pain), unstable or
- Arrhythmia (irregular heartbeat, within the last 6 months) or
- Blood vessel problems (eg, aortic stenosis, idiopathic subaortic stenosis) or
- Congestive heart failure or
- Heart attack (within the last 6 months) or
- Hypertension (high blood pressure), uncontrolled or
- Hypotension (low blood pressure) or
- Retinal disorders (eye problem) or
- Retinitis pigmentosa (an inherited eye disorder) or
- Stroke (within the last 6 months)—Should not be used in patients with these conditions.
- Bleeding disorders or
- Stomach ulcers—Chance of problems occurring may be increased; it is not known if the medicine is safe for use in these patients.
- Leukemia (blood-related cancer) or
- Multiple myelomas (blood-related cancer) or
- Sickle-cell anemia (blood disorder)—Avanafil should be used with caution in these patients as problems with prolonged erection of the penis may occur.
Pregnancy & Lactation
FDA Pregnancy category- C
Avanafil is not indicated for use in females. There are no adequate and well-controlled trials of avanafil in humans during pregnancy. Based on animal data, avanafil is predicted to have a low risk for major developmental abnormalities in humans.
Avanafil is not indicated for use in females and is therefore not recommended in breastfeeding-feeding. It is not known if avanafil is excreted in human breast milk.
There is no known indication for the use of avanafil in neonates, infants, or children. Avanafil should not be prescribed to these populations.
References
Explore this medical topic
Continue through verified related conditions, investigations, medicines, and patient guides. These links are educational and do not replace professional medical advice.
