BPH and Erectile Dysfuntion Pharmacology Flashcards
Lower urinary tract symptoms
- interrupted stream
- frequency
- hesitation
- fullness
- dribbling, urgency, weak stream
How do α1 adrenergic receptor antagonists relieve LUTS?
- reduce spasm
- promote muscle relaxation
- improve urine flow
terazosin specificity
α1»_space;>α2
doxazosin specificity
α1»_space;>α2
tamsulosin specifcity
α1A = α1D > α1B
silodosin specificity
α1A = α1D > α1B
alfuzosin
non specific α1 selective
adverse effects terazosin
postural hypotension, dizziness, fatigue
adverse effects doxazosin
postural hypotension, dizziness, fatigue
adverse effects tamsulosin
reduced ejaculation, intraoperative floppy iris syndrome
adverse effects silodosin
reduced ejaculation, intraoperative floppy iris syndrome
adverse effects alfuzosin
QT prolongation
What is best singular Tx for prompt relief of LUTS with BPH?
α1 adrenergic receptor antagonists (relieves Sx in days)
What α1 adrenergic receptor antagonist has functional uroselectivity?
Alfuzosin
How do steroid 5α reductase inhibitors blunt prostate enlargement?
inhibit SAR-1 and SAR-2 which starves the prostate of DHT, which causes the prostate to atrophy and shrink
What do steroid 5α reductase inhibitors do?
blunt prostate enlargement
What does finasteride do?
Decrease DHT by inhibiting SAR-2 (specifically)
What does dutasteride do?
Decrease DHT by inhibitng SAR-1 and SAR-2 (dual inhibitor)
How long does it take for steroid 5α reductase inhibitors to work?
about 3 months for measurable effect
What pharmacologic intervention should be used for severe BPH?
steroid 5α reductase inhibitors and α1 adrenergic receptor antagonists
What is tadalafil (cialis)?
PDE-5 inhibitor used to treat BPH and erectile dysfunction
What PDE-5 inhibitor has by far the longest half life and duration of action?
tadalafil (cialis)
What PDE-5 inhibitor has the fastest onset?
avanafil (stendra)
What drug is contraindicated to use with PDE-5 inhibitors and why?
Organic nitrates (NTG) due to possible severe and dangerous hypotension
What is priapism and why is it a medical emergency?
prolonged erection, it is a medical emergency because it can result in permanent corporal fibrosis and erectile dysfunction
what is alprostadil and what is it for?
prostaglandin E1 agonist, penile injection for erectile dysfunction
Action of alprostadil
increase PGE1, increase adenylate cyclase activity, and increase cAMP to cause erection
