Avanafil Indications Contraindications, Warning

Avanafil Indications Contraindications
Avanafil Indications Contraindications/Avanafil is an orally available phosphodiesterase type 5 (PDE5) inhibitor with vasodilatory activity. Avanafil selectively inhibits PDE5, thus inhibiting the degradation of cyclic guanosine monophosphate (cGMP) found in the smooth muscle of the corpus cavernosa of the penis. The inhibition of cGMP degradation results in prolonged muscle relaxation, vasodilation, and blood engorgement of the corpus cavernosa, thereby prolonging penile erection.

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

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Contra-Indications of Avanafil

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

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Common 

Rare

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.

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 (a 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.
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Pregnancy & Lactation

FDA Pregnancy category- C

Pregnancy

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.

Lactations

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

Avanafil Indications Contraindications