drugs for erectile dysfunction

Question 1

alprostadil moa

Answer 1

synthetic PGE1; stimulates adenylate cyclase, increasing cAMP, which stimulates PKA, which causes a decrease in intracellular Ca2+ leading to smooth muscle relaxation

Question 2

alprostadil administration

Answer 2

suppository in penis or injection in corpus cavernosum

Question 3

alprostadil adverse effects

Answer 3

penile, urethral, or testicular pain

Question 4

PDE-5 inhibitors

Answer 4

tadalafil, vardenafil, sildenafil, avanafil

Question 5

pde-5 inhibitors adverse effects

Answer 5

optic neuropathy, hearing loss, angina (except sildenafil), and myocardial infarction (tadalafil and vardenafil only)

Question 6

PDE-5 inhibitor with longest half life

Answer 6

tadalafil

Question 7

PDE-5 inhibitor interactions

Answer 7

nitrates (absolute contraindication), alpha blockers (high risk of hypotension), and drugs affecting CYP activity (because they all undergo extensive CYP metabolism)

Question 8

yohimbine moa

Answer 8

alpha-2 receptor blocker, decreases intracellular calcium leading to relaxation; antagonizes presynaptic inhibition of the NANC nerves and increases NO release; crosses BBB

Question 9

yohimbine adverse effects

Answer 9

CNA: dizzy, anxiety, irritability
sinus tachycardia
MAOI action at supra clinical doses
worsens renal function
tyramine and caffeine interactions