II. Indications
III. Contraindications
- See Phosphodiesterase Inhibitors (PDE5 Inhibitors)
- Men using nitrates (causes profound Hypotension)
- Men using alpha blockers (e.g. Hytrin for BPH)
IV. Mechanism
V. Dosing
- Start 20 mg PO 1 hour before intercourse
- Do not take more than once per 2 days
- Most insurance limits to 6 per month
- Indications to start with half dosing (10 mg)
- Age over 65 years
- Hepatic Impairment
- Renal Impairment
- Concurrent use of Cytochrome P3A4 inhibitor below
VI. Pharmacokinetics
- Onset within 30 to 60 minutes
- Duration as long as 36 hours
- Contrast with 4 hours with Viagra
- Prolonged effect also leads to prolonged side effects
VII. Adverse Effects: Viagra (but most apply to the PDE5 Inhibitor Class as a whole)
- See Phosphodiesterase Inhibitors (PDE5 Inhibitors)
- Hypotensive effect for men on Nitrates (Avoid)
- Vision effects (color Vision, Vision Loss)
- Sensorineural Hearing Loss
- Mild Headache (21%)
VIII. Efficacy
- Also appears effective in Benign Prostatic Hyperplasia (BPH)
- May be preferred over Tamsulosin in BPH with comorbid Erectile Dysfunction
- Rohrbough (2024) Am Fam Physician 109(1): 83-4 [PubMed]
IX. Drug Interactions
- See Phosphodiesterase Inhibitors (PDE5 Inhibitors)
- Profound Vasodilitation and Hypotension with Nitroglycerin and alpha blockers such as Prazosin (Avoid)
- Avoid nitrates within 48 hours of Tadalafil (Cialis)
- Cytochrome P3A4 related interactions (Cimetidine, systemic Antifungals, Protease Inhibitors and Macrolides
X. References
Images: Related links to external sites (from Bing)
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