Male GU Pharmacology Flashcards
What are the three families of drugs to treat Benign Prostatic Hypertrophy?
A1 antagonists, steroid 5alpha reductase inhibitors, and PDE 5 inhibitors.
What alpha1 subtype is more common on vascular, prostate smooth muscle, detrusor instability, and spinal cord for urinary function?
A1b > A1a, A1a, A1d>A1a, and A1d
What subtype is terazosin and doxazosin selective for, and what are the 3 adverse effects?
A1 over A2. Postural hypotension, dizziness, and fatigue.
What is the selectively for tamsulosin and silodosin? What are 2 adverse effects?
A1a=A1d>a1b.
Reduced ejaculation and IFIS.
What is the selectively for Alfuzosin and what is the one adverse effect?
Non specific A1.
QT Prolongation.
What is unique about alfuzosin and its selectivity?
It is uroselective, meaning it goes after A1 in the prostate far more than serum.
Two big reasons why the prostate enlarges?
Age and too much dihydrotestosterone
So, what is the problem with dihydrotestosterone and the prostate.
Testosterone and DHT cause the epi of the prostate to grow. Well DHT is way more potent than T. SAR converts T to DHT, so we inhibit SAR.
What are the 4 effects of inhabiting SAR?
More T, less DHT, less androgen binding to receptor in prostate, less gene transcription inside prostate ep cells.
SAR has two types, 1 and 2. The SAR inhibitors are finasteride and dunasteride. Which ones do they inhibit?
Finasteride inhibits 2 and dunasteride inhibits 1 and 2.
Which SAR type is found more in BPH?
SAR 2
Which drug decreases serum SAR more?
Dunasteride
You should avoid alfuzosin for BPH in what patients?
Patients with liver impairment
How long do SAR inhibitors take to begin having an effect?
About 3 months
What treatment do you use if there are severe symptoms of BPH or the prostate is just massive?
Combo A1 antagonist and SAR inhibitor
What drug to use if the patient has BPH and erectile dysfunction?
Tadalafil
What is the simple and easy pathway to an erection he gives?
Nitric oxide leads to lots of cGMP which decreases calcium and leads to smooth muscle relaxation and erection.
What is the onset of action for sild, vard, and tadalafil? What is the onset for avanafil?
Take one hour before.
Take 15 minutes before for high dose. Take 30 minutes before for normal dose.
What is the duration of action for sild, vard, and Ava? What is the duration of action for tadalafil?
- 36
What is the MAO for these PDE 5 inhibitors?
Stop PDE5 from converting cGMP to GMP so you have more cGMP around to lower the calcium.
What is an adverse effect for sildenafil, vardenafil, and avanafil and why?
Vision problems because they have some specificity for PDE6 receptor in the retina.
2 contraindications for using PDE5 inhibitors?
Do not use with nitrates (severe hypotension) and do not use with A1 antagonists for BPH.
Besides PDE5 antagonists, what other drug family do we use to treat erectile dysfunction?
PGE1 agonist
Quickly explain the pathway with PGE leading to an erection and the MOA for a PGE agonist?
PGE leads to adenylate cyclase which increases cAMP which lowers intracellular calcium, relaxing smooth muscle and getting an erection. So, the PGE agonist stimulates this process.
What is the adverse effect with Alprostadil, the PEG agonist, and how do you treat it?
Prolonged erection. Phenylephrine.
