Drugs used in BPH Flashcards
What short acting selective alpha-1 blockers are used to treat BPH?
- Prazosin
* Alfuzosin
What Long acting Selective alpha-1 blockers are used in BPH?
- Terazosin
* Doxazosin
What alpha-1 partially selective blockers are used in BPH?
- Tamsulosin
* Silodosin
What PDE-5 inhbititors are used to treat BPH?
• Tadalafil
What 5-alpha Reductase inhibitors are used to Treat BPH?
- Finasteride
* Dutasteride
Differentiate the locations of the alpha-1a and alpha-1d receptors?
- Alpha-1a - Predominates in lower GU tract (trigone through prostate and into urethra)
- Alpha-1d - predominates in the Detrussor muscle of the urinary bladder
What can be said about the following for the alpha-1 blockers?
• Metabolism
• Duration of Action
Metabolism:
• extensive CYP metabolism
Duration of Action:
• LONG duration of action EXCEPT for prazosin
Long Duration of action means compliance on these drugs is better
What makes the use of prazosin difficult?
• You need to Titrate the dose because the drug shows great variability from patient to patient
What are common side effects of all of the alpha-1 blockers?
- Orthostatic Hypotension, Syncope
* Xerostomia, Nausea, Dizziness, Somnolence, Asthenia, Headache, Insomnia
Tamsulosin and Sildosin
• MOA?
• Specific Side effects?
MOA:
• partially selective alpha-1a antagonists
Side effects that differ from other alpha-antagonists:
•Diminished CV function
• Increased Sexual (ejaculation) dysfunction
What is the best alpha blocker currently used to treat BPH?
• why?
• Alfuzosin - has no significant effects on dizziness, asthenia, and ejaculatory dysfunction
How do PDE-5 inhibitors work to increase urine flow?
- PDE5 breaks down cGMP made by Guanylyl Cylcase in response to NO stimulation
- Blocking PDE5 allows form more cGMP to activate PKG which phosphorylates Ca2+ channels allowing for Ca2+ efflux and smooth muscle relaxation
Tadalafil • aka? •use? • Side Effects? • Contraindications for use?
aka Cialis - PDE5 inhibitor
• relieves BPH
Side Effects = rare:
• Nasopharyngitis, URTIs
• Vision and hearing loss
Contraindications:
• DO NOT USE WITH ORGANIC NITRATES
• Profound Hypotension
• Exacerbated by alcohol consumption
What does 5-alpha-reductase do?
• what are the two different subtypes?
• where are they found?
• Catalyzes the conversion of Testosterone to dihydrotesterone.
2 subtypes:
• Type I: non-genital skin (liver, bone)
• Type II: Urogenital Tissue in men, and genital skin in men and women
What is special about dihydrotesterone?
- Binds with higher affinity than testosterone
* Activates gene expression more efficiently than testosterone
How do 5-alpha-reductase inhibitors work to reduce the effects of BPH?
• Reduce Dihydrotestosterone driven proliferation of the prostate
What 2 drugs act on 5-alpha-reductase?
• how do they differ?
- Finasteride - inhibits type 2
- Dutasteride - inhibits type 1 and 2 enzyme
besides receptor specificity differences, they are the same in all other ways
Finasteride and Dutasteride
• Administration
• Metabolism
• Pregnancy safety?
Administration:
• Oral
Metabolism:
• Heavy CYP3A4 metabolism
Pregnancy Category X (not carried in semen)
5-alpha reductase inhibitors.
• Name them.
• Side effects.
Finasteride (type 2) and Dutasteride (type 1 and 2)
Side Effects:
• Ejaculation Dysfunction, decreased libido, Gynecomastia (man boobs)
• Decreased PSA levels
What is the issue of giving finasteride or dutasteride to someone with prostate cancer?
• These drugs may decrease PSA levels
**They also may increase the cancer of getting prostate cancer
What is the use of Beta-Stiosterols for BPH?
*Reduce SYMPTOMS of BPH but do NOT decrease prostate size significantly
What is Saw Palmetto’s use in BPH?
*Unlike Beta-Stiosterols, there is not significant change in side effects with using Saw Palmetto
