Sildenafil
Administration
- Type: PDE-5 inhibitor
- Dosage Forms:
- Routes of Administration: PO, IV
- Common Trade Names: Viagra, Fildena, Revatio
Adult Dosing
- Pulmonary hypertension: 5-20mg PO TID or 2.5-10 mg IV bolus TID
- Erectile dysfunction: 25-100mg PO 1hr prior to sexual activity, max once daily
Pediatric Dosing
Not generally recommended for chronic use in pediatric patients, but is used off-label
Special Populations
- Pregnancy Rating: B
- Lactation risk: Infant risk cannot be ruled out
- Renal dosing: no adjustment
- Hepatic dosing: no adjustment for mild-moderate impairment
Contraindications
- Allergy to class/drug
- Concurrent regular or intermittent use of any organic nitrates
- Concomitant use with HIV protease inhibitors or elvitegravir/cobicistat/tenofovir/emtricitabine
- Concomitant use with riociguat or any other guanylate cyclase stimulator
Adverse Reactions
Serious
- Myocardial infaction
- Sickle cell vasoocclusive crisis
- Ischemic optic neuropathy, retinal hemorrhage
- Hearing loss
- Priapism
Common
- Headache
- Insomnia
- Visual disturbance
- Erythema, flushing
- Indigestion
- Epistaxis, nasal congestion, rhinorrhea
Pharmacology
- Half-life: 4h
- Metabolism: Hepatic: CYP3A4 (major) and CYP2C9 (minor)
- Excretion: Mostly fecal
Mechanism of Action
- Inhibits cGMP specific phosphodiesterase type-5 (PDE5) in smooth muscle→ less cGMP breakdown→ more cGMP within vascular smooth muscle→ vascular smooth muscle relaxation→ vasodilation