(10.1) BPH and ED pharmacology (Sheehy) Flashcards
Describe what benign prostatic hypertrophy (BPH) is:
BPH causes bladder outlet obstruction
Prostate gets enlarged and blocks urethra, urine gets blocked
What are the lower urinary tract symptoms (LUTS) asociated with BPH?
Interrupted stream
Frequency
Hesitation
Fullness
Dribbling
Urgency
Weak stream
What class of drugs are used to treat BPH?
Alpha1 adrenergic receptor antagonists
What drugs are used to treat BPH?
-OSIN
Terazosin
Doxazosin
Tamsulosin
Sildosin
Alfuzosin
What is the main goal of alpha1 adrenergic receptor antagonists in treating BPH?
Relax muscle tone
Describe the receptor specificity of
Terazosin
Doxazosin
Tamsulosin
Sildosin
Alfuzosin
Which of the following alpha 1 adrenergic receptor antagonists is uroselective
Terazosin
Doxazosin
Tamsulosin
Sildosin
Alfuzosin
Tamsulosin
Silodosin
Alfuzosin
What are the adverse effects of these drugs?
Terazosin
Doxazosin
Tamsulosin
Sildosin
Alfuzosin
What are the drug interactions of
Terazosin
Doxazosin
Tamsulosin
Sildosin
Alfuzosin
What are the structural remedy drugs for BPH?
Steroid 5alpha reductase inhibitors
Finasteride
Dutasteride
How do steroid 5alpha reductase inhbitors act as a structural remedy for BPH?
Prevent enlargement and shrink the prostate
What are the downsides to taking finasteride or dutasteride?
DELAYED ACTION
Shrinkage and symptom relief takes 3-6 months
Why does the prostate enlarge?
Aging
+
Dihydrotestosterone
Physiologically, how do steroid 5alpha reductase inhibitors work?
DHT is 10 times more potent than T
SAR type 1 and 2 convert serum T to DHT in cells
A prostate that has undergone hyperplasia has excess SAR2
DHT “starvation” causes epithelial atrophy, shrinkage and gradual relief of LUTS
Descibe the enzyme selectivity of Finasteride
Finasteride
is a….
SpeciFIc inhibitor
SAR-2
Descibe the enzyme selectivity of Dutasteride
Dutasteride
is a…
DUal inhibitor
SAR-1 and SAR-2
Which SAR is more prevalent in BPH?
SAR-2
Explain why the serum DHT levels are:
70% decreased with finasteride
90% decreased with dutasteride
Finasteride is SPECIFIC to SAR-2, which is primarily in the prostate
Dutasteride is DUAL acting on SAR-1 and SAR-2 and will have a greater systemic influence on serum DHT
What are the adverse effects of finasteride and dutasteride?
Erectile dysfunction
Gynecomastia
Depressed libido
Ejaculation disturbances
Is it possible to administer a combo therapy for BPH?
YES!
Use combo therapy when pt. has no response to monotherapy
Define:
Erectile dysfunction (ED)
Consistent or recurrent inability to acquire or sustain an erection of sufficient rigidity and duration for sexual intercourse
What are some risk factors for ED?
Obesity
Smoking
Stress
How do PDE-5 inhibitors work to sustain an erection?
What PDE-5 inhibitor has the longest half life?
Tadalafil
What is the fastest acting PDE-5 inhibitor?
Avanafil
What PDE-5 inhibitor has the longest duration of action?
Tadalafil
What are some side effects of PDE-5 inhibitors?
Reasonably well tolerated
PDE-5 related = headache, dyspepsia, nasal decongestion
PDE-6 related = blue/blurred vision
Specific to tadalafil = Back pain, myalgia, limb pain
What is a MAJOR contraindication of PDE-5 inhibitors?
ORGANIC NITRATES
–> Extreme and dangerous hypotension
What are second-line ED therapies?
Vacuum erection devices
Penile injections w/ alprostadil
What is a major side effect of alprostadil?
Priapism
C. Nitrovasodilator (i.e. nitroglycerin)
