Overview
11 DESCRIPTION Avanafil is a selective inhibitor of cGMP-specific PDE5. Avanafil is designated chemically as (S)-4-[(3-Chloro-4-methoxybenzyl)amino]-2-[2-(hydroxymethyl)-1-pyrrolidinyl]- N -(2-pyrimidinylmethyl)-5-pyrimidinecarboxamide and has the following structural formula: Avanafil occurs as an off-white to white powder, molecular formula C 23 H 26 ClN 7 O 3 and molecular weight of 483.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate cyclase, which results in increased levels of cGMP, producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood. Avanafil has no direct relaxant effect on isolated human corpus cavernosum, but enhances the effect of NO by inhibiting PDE5, which is responsible for degradation of cGMP in the corpus cavernosum. Because sexual stimulation is required to initiate the local release of nitric oxide, the inhibition of PDE5 has no effect in the absence of sexual stimulation. Studies in vitro have shown that avanafil is selective for PDE5.
Indications
- 1 INDICATIONS AND USAGE Avanafil tablets are a phosphodiesterase 5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction in adult males. Avanafil tablet is a phosphodiesterase 5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction ( 1 )
Common Doses
- 100 mg
- 200 mg
- 50 mg
Dosage
2 DOSAGE AND ADMINISTRATION • The starting dose is 100 mg taken as early as approximately 15 minutes before sexual activity, on an as needed basis ( 2.1 ) • Take avanafil tablet no more than once a day ( 2.1 ). • Based on efficacy and/or tolerability, the dose may be increased to 200 mg taken as early as approximately 15 minutes before sexual activity or decreased to 50 mg taken approximately 30 minutes before sexual activity. Use the lowest dose that provides benefit ( 2.1 ). • Avanafil tablet may be taken with or without food ( 2.
Contraindications
- 4 CONTRAINDICATIONS • Administration of avanafil tablet to patients using any form of organic nitrate is contraindicated ( 4.1 ) • Hypersensitivity to any component of the avanafil tablet ( 4.2 ) • Administration with guanylate cyclase (GC) stimulators such as riociguat and vericiguat ( 4.3 ) 4.1 Nitrates Administration of avanafil tablets with any form of organic nitrates, either regularly and/or intermittently, is contraindicated.
Side Effects
- 6 ADVERSE REACTIONS Most common adverse reactions (greater than or equal to 2%) include headache, flushing, nasal congestion, nasopharyngitis, and back pain ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Hetero Labs Limited at 1-866-495-1995 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Interactions
- 7 DRUG INTERACTIONS • Avanafil can potentiate the hypotensive effect of nitrates, alpha-blockers, antihypertensives, and alcohol ( 7.1 ) • CYP3A4 inhibitors (e.g., ketoconazole, ritonavir, erythromycin) increase avanafil exposure ( 7.2 ) 7.1 Potential for Pharmacodynamic Interactions with Avanafil Nitrates Administration of avanafil to patients who are using any form of organic nitrate, is contraindicated. In a clinical pharmacology trial, avanafil was shown to potentiate the hypotensive effect of nitrates.