Last updated: October 29, 2014
Trade Names: Cialis, Adcirca
Drug Class: Phosphodiesterase 5 (PDE5) inhibitor
Preparations: 2.5-, 5-, 10-, 20 mg tablets
Dose: For pulmonary hypertension 40 mg once daily; for erectile dysfunction 2.5-5 mg once daily or 5-20 mg episodically (not more than once daily) before sexual activity
Mechanism of Action: Inhibits PDE5 and thus increases cyclic GMP concentrations causing vasodilation
Contraindications: Hypersensitivity, concurrent use of any form of nitrates, including ointment
Precautions: Potential for drug interactions
Pregnancy Risk: B
Common: Flushing, headache, dyspepsia, dizziness
Less common: Visual disturbance including color changes, allergy, rash, hearing loss, hypotension (particularly with nitrates or cytochrome P450 (CYP) 3A inhibitors), priapism
CYP3A inhibitors (strong inhibitors include clarithromycin, telithromycin, ketoconazole, itraconazole, nefazodone and many HIV drugs; moderate inhibitors include aprepitant, diltiazem, verapamil, erythromycin, fluconazole, posaconazole, voriconazole, grapefruit juice): increased tadalafil concentrations.
Nitrates: Hypotension; avoid this combination
Alpha-1 blockers: Increased risk of hypotension
Patient Instructions: Avoid grapefruit juice; stop drug if have sudden visual or hearing loss
Comments: Small studies or case-series suggest PDE5 inhibitors are modestly effective for Raynaud’s and for digital ulcers associated with scleroderma.
Clinical Pharmacology: Onset 60 minutes, half-life 15-35 h. Metabolized by CYP3A4.
Roustit M, Blaise S, Allanore Y, et al.vPhosphodiesterase-5 inhibitors for the treatment of secondary Raynaud's phenomenon:systematic reviewand meta-analysis of randomised trials. Ann Rheum Dis 2013;72:1696-9. PMID: 23426043.
Tingey T, Shu J, Smuczek J, Pope J. Meta-analysis of healing and prevention of digital ulcers in systemic sclerosis. Arthritis Care Res 2013;65(9):1460-71.PMID: 23554239.