Table 1.

Comparison of the properties of PDE5-inhibitors

Property	Sildenafil	Tadalafil	Vardenafil
>TMAX	30–120 minutes (median 60 minutes)	30–360 minutes (median 120 minutes)	30–120 minutes (median 60 minutes)
T ½	4 hours	17.5 hours	4 hours
Absorption	Fatty meals cause a mean delay in TMAX of 60 minutes	Not affected by food	Fatty meals cause a reduction in CMAX
Available Doses	25 mg, 50 mg, 100 mg PRN	2.5 mg, 5 mg daily 5 mg, 10 mg, 20 mg PRN	10 mg oral dissolvable tablet 2.5 mg, 5 mg, 10 mg, 20 mg PRN
Maximum Dose	100 mg daily	20 mg daily	20 mg daily
Efficacy	Each of the PDE5 inhibitors offers similar efficacy.
Dose adjustments may be needed	Patients >65 years old Hepatic impairment Renal impairment Concomitant use of potent cytochrome P450 3A4 inhibitors, such as ritonavir and erythromycin Concomitant use of cimetidine	Patients >65 years old Hepatic impairment Renal impairment Concomitant use of potent cytochrome P450 3A4 inhibitors, such as ritonavir and erythromycin	Patients >65 years old Hepatic impairment Renal impairment Concomitant use of potent cytochrome P450 3A4 inhibitors, such as ritonavir and erythromycin
Contraindications	Any patient using organic nitrates either regularly or intermittently Known hypersensitivity to any component of the tablet	Any patient using organic nitrates either regularly or intermittently Known hypersensitivity to any component of the tablet	Any patient using organic nitrates either regularly or intermittently Known hypersensitivity to any component of the tablet
Use with alpha blockers	Concomitant use of selective alpha blockers does not present a risk for significant hypotension. There is a potential risk of significant hypotension when using non-selective alpha blockers.
Side effects (5 most common in order of frequency when compared to placebo)	Headache, flushing, dyspepsia, nasal congestion, alteration in colour vision	Headache, dyspepsia, backpain, myalgia, nasal congestion	Headache, flushing, rhinitis, dyspepsia, sinusitis

Please consult the individual product monographs for additional information.