□
Drugs for treatment of erectile dysfunction
TomasGonec 21.11.2011
Erectile dysfunction
PDE V. inhibitors
□ Mechanism of action:
cCMP-gated
Afloni^t tor channels
Cavernous nerve endothelial cell Smooth muscle relaxation
Cupyrigiit -fi        Nature PuMiihiny Croup Nature Reviews | Drug Discovery
11
PDE V. inhibitors
□ xanthin analogues Sildenafil, Tadalafil, Verdanafil
Table I Pharmacokinetics of the three PDE5 inhibitors14
Drug	T (h)a max * *	Earliest onset of action (min)	T,„ <h)s	Duration of effect (h)	Recommended dosing time (h) prior to intercourse
Sildenafil 100 mg	1	30	4	4-6 (up to 12)	1
Tadalafil 20 mg	2	20	17.5	24-36 (up to72)	0.5-12
Vardena.fi! 20 mg	0.7	10	4.5	5-7 (up to 12)	0.5-1
aT    time needed to reach maximum plasma concentration (C    ), which corresponds to onset of action.
mas 1 v   nax ' r
bT|ra half-life, which corresponds to duration of efficacy.
PDE V. inhibitors
□ Sildenafil (Viagra, Revatio)
11
PDE V. inhibitors
11
PDE V. inhibitors
Side effects
fable 2 Side effects of PDE5 inhibitors
Side effect	Sildenafil	Vardenafil	Tadalafil
Headache	14.6%	14.5%	14%
Flush	14.1%	11.1%	4%
Dyspepsia	6.2%	3.7%	10%
Rhinitis	2.6%	9.2%	5%
Back pain	0%	0%	6%
Visual disturbances	5.2%	0%	0%