Urogenital Pharm Flashcards
a1 adrenergic antagonists
Doxazosin, terazosin, alfuzosin, tamsulosin, silodosin
Steroid 5a-reductase inhibitors
Finasteride, Dutasteride
Phosphodiesterase-5 inhibitors
Sildenafil, Vardenafil, tadalafil
Role of a1 adrenergic antagonists
Drugs that relax muscle tone
Dynamic remedy
Rapid relief of symptoms
-compete with NE to reduce spasm, promote muscle relaxation and improve urine flow
Prostate a1 receptors
Smooth muscle contraction
a1A
Detrusor a1 receptors
Instability
a1D>a1A
Spinal cord a1 receptors
Control of urinary function
a1D
Blood vessels a1 receptors
Vascular resistance
a1B>a1A
Sub-type specific a1-antagonists
Tamsulosin and silodosin a1A=a1D>a1B
Side effect of Terazocin and Doxazosin
Orthostatic hypotension
-Must titrate the first dose
Alfuzosin adverse effect
QT prolongation
Tamsulosin and silodosin adverse effect
Intraoperative floppy iris syndrome
-Reduced ejaculation
SARI MOD
- Prevents enlargement and shrinks prostate
- Structural remedy
- Delayed action: shrinkage takes 3-6 months
What receptor is over expressed in a hypertrophic prostate?
SAR II
- Inhibit this because it is prostate specific
- Can’t dimerize and go to the nucleus to increase transcription
Dutasteride
Dual inhibitor SAR1 and 2
Finasteride
Specific inhibitor
SARII
What is the only PDE-5 inhibitor approved by FDA to treat BPH?
Tadalafil
How does NO cause as erection?
Combines with guanlyate cyclase to activate cGMP that relaxes smooth muscle
What is PDE5 role in an erection?
cGMP gets reversed by PDE-5 to end the erection by removing the vasodilation
-Thus the antagonists keep cGMP at higher levels
What is the main contraindication to PDE-5 inhibitors?
Organic nitrates combined with PDE-5 inhibitors produce extreme hypotension
-Organic nitrates are regularly used in coronary artery disease and with angina pectoris (they release NO)
