PHARM: Erectile Dysfunction Flashcards
What is the only drug for erectile dysfunction that is not oral?
alprostadil
What is the ROA of alprostadil?
Either intra-
urethral suppository placed there to dissolve in residual urine and
to be absorbed across the urethral wall. The other option is by
direct injection onto the corpus cavernosum, taking care to avoid
the top or bottom of the penis.
What is the PGE1 synthetic mimic used for erectile dysfunction?
Alprostadil
What are the PDE-5 inhibitors used for erectile dysfunction?
Avanafil
Sildenafil
Tadalafil
Vardenafil
What hormone replacement therapies are used for erectile dysfunction?
Methyltestosterone
Testosterone
What is the alpha-2 receptor antagonist used for erectile dysfunction?
Yohimbine
What is the short-acting selective alpha-1 blocker used for erectile dysfunction?
Alfuzosin
MOA: Activates adenylate cyclase, which synthesizes cAMP from ATP. cAMP acts as a second messenger activating protein kinase A, which results in an efflux of intracellular calcium and subsequent smooth-muscle relaxation and erection.
alprostadil
MOA: Decrease the breakdown of cGMP by inhibition of PDE5, resulting in the prolonged high levels of cGMP necessary for erections.
Avanafil
Sildenafil
Tadalafil
Vardenafil
MOA: Cause relaxation of the smooth muscle in the prostatic and penile urethra, thereby permitting easier urination.
alfuzosin
What are the two main mechanisms by which yohimbine decreases intracellular calcium to relax penile smooth muscle?
- Antagonizes the stimulation of alpha2-ARs by NE released from adrenergic nerve terminals
- Antagonizes the presynaptic inhibition of the Non-Adrenergic Non-Cholinergic nerves and increases the release of NO, which stimulates soluble guanylate cyclase to synthesize cGMP
Why does alprostadil have very few CV side effects?
delivery options for alprostadil allows for avoidance of systemic drug effects
How quickly does alprostadil work?
). Action occurs fast (minutes) and has a durable effect (30 min to several hours).
What are the most common adverse effects of alprostadil?
Penile, urethral and testicular pain
What is the most common adverse effect of PDE-5 inhibitors?
headache
What are the common serous toxicities of PDE-5 inhibitors?
cardiovascular issues, sudden loss of hearing and sight
What drug class is contraindicated with PDE-5 inhibitors?
ORGANIC NITRATES! Both agents would produce vasodilation, albeit by different mechanisms, leading to severe and life-threatening hypotension!
What other drugs may interact with PDE-5 inhibitors?
alpha blockers (increase hypotension) and drugs affecting CYP activity
Which PDE-5 is most likely to elicit QT prolongation with concurrent meds?
Vardenafil has interactions with over 70 drugs—making it the most likely to produce QT prolongation→ cardiac arrhythmia!
Testosterone may be used with what drug to enhance its effect?
improve the response of hypogonadal men to PDE5 inhibitors like sildenafil citrate
TRUE or FALSE, yohinbine crosses the BBB easily?
TRUE– leads to anxiety, antidiuresis, dizziness, flushing, HA, HTN, increased motor activity, irritability, nervousness or restlessness, sinus tachycardia, tremor
At supra-clinical doses, what actions does yohimbine have?
MAOI actions
In what patients is yohimbine contraindicated?
Patients with renal failure or dysfunction
