STENDRA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for STENDRA (STENDRA).
Selective inhibitor of phosphodiesterase type 5 (PDE5), enhancing cyclic guanosine monophosphate (cGMP) accumulation in corpus cavernosum, leading to smooth muscle relaxation and increased penile blood flow.
| Metabolism | Primarily hepatic through CYP3A4, with minor contribution from CYP2C9; metabolite M1 also active. |
| Excretion | Fecal (approximately 63%) and renal (approximately 21%) as metabolites; less than 2% excreted unchanged in urine. |
| Half-life | Terminal elimination half-life is approximately 4 hours in healthy subjects; may be prolonged in hepatic impairment (Child-Pugh B: up to 6 hours) or with concomitant CYP3A4 inhibitors. |
| Protein binding | Approximately 99% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Approximately 2 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is approximately 40% under fasting conditions; reduced by 30–40% when taken with a high-fat meal. |
| Onset of Action | Oral: Approximately 30–60 minutes; maximal effect within 1–2 hours under fasting conditions. |
| Duration of Action | Up to 4–6 hours; clinical efficacy may persist up to 12 hours in some patients, but recommended dosing interval is once daily as needed. |
| Molecular Weight | 488.6 |
50 mg orally once daily as needed, 1 hour before sexual activity. Maximum dose 100 mg. Maximum frequency once daily.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-50 mL/min: 50 mg initially. CrCl <30 mL/min: not recommended. |
| Liver impairment | Child-Pugh A: 50 mg initially. Child-Pugh B: 25 mg initially. Child-Pugh C: not recommended. |
| Pediatric use | Not approved for pediatric use. |
| Geriatric use | No specific adjustment. Consider lower starting dose (25 mg) due to age-related decreased clearance. |
| 1st trimester | Contraindicated due to risk of fetal harm; no adequate studies in pregnant women. |
| 2nd trimester | Contraindicated; may cause fetal hypotension and decreased placental perfusion. |
| 3rd trimester | Contraindicated; risk of persistent pulmonary hypertension of the newborn. |
Clinical note
Comprehensive clinical and safety monograph for STENDRA (STENDRA).
| Placental transfer | Likely crosses placenta due to low molecular weight; no specific data on extent. |
| Breastfeeding | Excreted in breast milk in low amounts; however, due to potential for serious adverse effects in nursing infants, use is not recommended. Decision to breastfeed should be based on importance of drug to mother and risk to infant. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Concurrent use of nitrates (any form) or nitrite donorsConcurrent use of guanylate cyclase stimulators (e.g., riociguat)Hypersensitivity to avanafil or any componentSevere hepatic impairment (Child-Pugh class C)End-stage renal disease requiring dialysisSevere hypotension (systolic BP <90 mmHg)Recent myocardial infarction (within 6 months)Unstable angina or angina during sexual activityNew York Heart Association class II-IV heart failureUncontrolled arrhythmias, stroke (within 6 months)Retinitis pigmentosa or other degenerative retinal disordersHistory of non-arteritic anterior ischemic optic neuropathy
| Precautions | Cardiovascular risk: use with caution in patients with left ventricular outflow obstruction, hypotension, or severe hepatic impairment., Avoid use with nitrates due to risk of severe hypotension., Priapism: advise patients to seek immediate medical attention if erection persists >4 hours., Hearing loss: rare cases of sudden decrease or loss of hearing. |
| Food/Dietary | Avoid grapefruit and grapefruit juice due to CYP3A4 inhibition. High-fat meals may delay absorption and reduce peak concentration. |
Loading safety data…
| L4 - Possibly Hazardous |
| Teratogenic Risk | Pregnancy Category B: Animal studies have not demonstrated fetal risk, but no adequate human studies in pregnant women. Use only if clearly needed. First trimester: No known teratogenic effects. Second and third trimesters: No documented adverse fetal outcomes. However, due to potential uterine hyperstimulation and placental hypoperfusion, avoid use in pregnancy unless benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal blood pressure and heart rate during treatment. Fetal monitoring should include heart rate assessment if administered near term due to possibility of uterine hyperstimulation. In cases of overdose or prolonged erection, monitor for signs of priapism. |
| Fertility Effects | No specific studies on fertility. In animal studies, no impairment of fertility was observed at doses up to 60 mg/kg/day (approximately 25 times the MRHD). There is no evidence of permanent adverse effects on fertility in humans. |
| Clinical Pearls | STENDRA (avanafil) is a PDE5 inhibitor with rapid onset (~15-30 min) and shorter half-life (~5 hours) compared to sildenafil. Avoid use with nitrates and alpha-blockers (except tamsulosin 0.4 mg). Dose adjustment needed for moderate hepatic impairment (Child-Pugh B) or strong CYP3A4 inhibitors. Not recommended with severe hepatic impairment, end-stage renal disease, or hypotension (SBP <90 mmHg). |
| Patient Advice | Take STENDRA approximately 15-30 minutes before sexual activity. · Do not take more than one dose per day. · Avoid grapefruit juice as it may increase drug levels. · Seek immediate medical help if you experience sudden vision loss, hearing loss, or an erection lasting more than 4 hours. |