PDE TYPE 5 INHIBITORS Flashcards
Phosphodiesterase type 5 inhibitors - indication
Erectile dysfunction
Primary pulmonary hypertension
Phosphodiesterase type 5 inhibitors - MOA
sexual stimulation > releases NO > cGMP production > vasodilatation (penile blood flow) + subsequent erection
cGMP is broken down by PDE-5 (inhibiting erection from occuring)
PDE-5 inhibitors (Slidenafil) block the breakdown of cGMP = increasing [cGMP]
This improves penile blood flow + erection quality
Note - STILL REQUIRE SEXUAL STIMULATION
Phosphodiesterase type 5 inhibitors - example
Slidenafil
Phosphodiesterase type 5 inhibitors - adverse effects (common)
Flushing
Headache
Dizziness
Phosphodiesterase type 5 inhibitors - adverse effects (serious)
Priapism
hypotension
tachycardia
vascular events (e.g.- MI, stroke)
Phosphodiesterase type 5 inhibitors - adverse effects - what should prompt urgent medical attention?
Priapism - if erection fails to subside for a prolonged period of time (2hrs after sexual stimulation) - this could lead to penile damage
Visual disorders (e.g.- colour distortion)
Phosphodiesterase type 5 inhibitors - contraindications (avoid)
stroke
ACS
CVD
Phosphodiesterase type 5 inhibitors - cautions (2)
Hepatic impairments
Renal impairments
Note - in these patients the dose should be reduced (or if possible avoid use of this drug)
Phosphodiesterase type 5 inhibitors - interactions
mainly Nitrates
Vasodilators - alpha blockers and CCB
cytochrome p450 inhibitors - amiodarone, diltiazem and fluconazole
Phosphodiesterase type 5 inhibitors - administration
Absorption and onset of effect will be DELAYED if taken WITH food
Phosphodiesterase type 5 inhibitors - communication
Explain to men that you are prescribing a drug to help them to have and maintain an erection BUT the drug will still require sexual stimulation in order to work
Advise taking medication 1 hour before sex
