PDE5 Inhibitors

Question 1

Sildenafil citrate (viagara)

Answer 1

Class: PDE5 inhibitor

Mechanism of action: Binding to the catalytic site of PDE5 and inhibiting the breakdown of cGMP which causes a decrease in calcium causing a smooth muscle relaxation and erection.

Therapeutic uses: ED-does not cause erection just makes it easier to upon arousal

Toxicity: Headache, dizziness, change in vision (NAION), flushing, upset stomach, nasal congestion, UTI, diarrhea

Other: oral once a day (no more), half life 4 hours, peak concentration in 1-2 hours, contraindicated in patients on nitrates or alpha blockers (unsafe drop in BP)

Question 2

Vardenafil HCl (levitra)

Answer 2

Class: PDE5 inhibitor

Mechanism of action: Binding to the catalytic site of PDE5 and inhibiting the breakdown of cGMP which causes a decrease in calcium causing a smooth muscle relaxation and erection.

Therapeutic uses: ED-does not cause erection just makes it easier to upon arousal

Toxicity: Headache, dizziness, change in vision (NAION), flushing, upset stomach, nasal congestion, UTI, diarrhea

Other: oral once a day (no more), half life 4 hours, peak concentration in 1-2 hours, contraindicated in patients on nitrates or alpha blockers (unsafe drop in BP)

Question 3

Tadalafil (cialis)

Answer 3

Class: PDE5 inhibitor

Mechanism of action: Binding to the catalytic site of PDE5 and inhibiting the breakdown of cGMP which causes a decrease in calcium causing a smooth muscle relaxation and erection.

Therapeutic uses: ED-does not cause erection just makes it easier to upon arousal

Toxicity: Headache, dizziness, change in vision (NAION), flushing, upset stomach, nasal congestion, UTI, diarrhea

Other: oral once a day (no more), half life 17.5 hours, peak concentration in 1-2 hours, contraindicated in patients on nitrates or alpha blockers (unsafe drop in BP)