Male Disorders Flashcards
(25 cards)
Alpha1 adrenergic antagonists (days to resolve)
- Doxazosin
- Terazosin
- Alfuzosin
- Tamsulosin
- Silodosin
BPH alpha1 adrenergic antagonists (months to resolve)
- Alfuzosin
- Tamsulosin
- Silodosin
Steroid 5alpha-reductase inhibitors
- Finasteride
2. Dutasteride
PDE5 inhibitors
- Sildenafil
- Vardenafil
- Tadalafil
Erectile dysfunction
- PDE5 inhibitors
2. Prostaglandin E1
BPH
- Alpha1 adrenergic Rc antagonists
- Steroid 5alpha-reductase inhibitors
- PDE5 inhibitors
Alpha 1 adrenoRc
Prostate - alpha 1A (muscle contraction)
Detrusor - alpha 1D > alpha 1A (instability)
SC - alpha 1D (control of urinary function)
BV - alpha 1B > alpha 1A (vascular resistance)
Alpha 1 antagonists compete with what to reduce spasm, promoter muscle relaxation and improve urine flow?
NE
Terazosin
- alpha 1 > alpha 2»_space; beta
- NON-SPECIFIC for alpha 1 subtypes
- NO uroselectivity
- AE - postural hypotension titrate 1st dose, fatigue
- drug interaction with PDE-5 inhibitor
Doxazosin
- alpha 1 > alpha 2»_space; beta
- NON-SPECIFIC for alpha 1 subtypes
- NO uroselectivity
- AE - postural hypotension titrate 1st dose, fatigue
- drug interaction with PDE-5 inhibitor
Alfuzosin
- alpha 1 > alpha 2»_space; beta
- NON-SPECIFIC for alpha 1 subtypes
- YES Uroselective (functional) –> distributed into prostate > serum, avoid in HEPATIC impairment (take it after same meal everyday)
- AE - QT prolongation
- Drug interaction with Cyp450
Tamsulosin
- Sub-type specific so used more
- Alpha 1A ~ alpha 1D > alpha 1B
- YES Uroselective
- AE - reduced ejaculation, intraoperative floppy iris syndrome (IFIS)
- Drug interaction with Cyp450
Silodosin
- Sub-type specific so used more
- Alpha 1A ~ alpha 1D > alpha 1B
- YES Uroselective
- AE - reduced ejaculation, intraoperative floppy iris syndrome (IFIS)
- Drug interaction with Cyp450
Why does the prostate enlarge?
- Age
2. DHT
T —> DHT
SAR type 1 and II or Steroid 5alpha-reductase
Direct and indirect effects of SAR II inhibition
- Direct - T accumulation and DHT depletion
2. Indirect - less AR Rc occupied
Finasteride
SpeciFic inhibitor (SAR II)
Dutasteride
DUal inhibitor
SAR I and II
Tadalafil
- for BPH
- Onset: 15 min (take 1h before)
- Span of efficacy: 36h 1x weekend
- Advice: none
- t1/2 (h): 18h
- clearance: hepatic CYP 3A4
- alpha 1 blockers not recommended when this is used
- Risk D: consider therapy modification
- SE: headache, dyspepsia, nasal congestion, back pain, myalgia, limb pain (NSAIDs ok)
What modulates smooth muscle tone of penis?
- Neuronal input (NANC)
- Endothelial lining
NO –> GC –> cGMP –> PHE-5 –> GMP –> SM relaxation and erection
Slidenafil (Viagra)
- Onset: 15mins (take 1h before)
- Span of efficacy: 3 to 4h
- Advice: empty stomach
- t1/2 (h): ~4h
- clearance: hepatic CYP 3A4
- SE: headache, dyspepsia, nasal congestion, blue vision (PDE-6)
- give alpha 1 blockers at LOWEST recommended dose in patients receiving sildenafil
Varfenafil
- Onset: 15mins (take 1h before)
- Span of efficacy: 4 to 5h
- Advice: empty stomach
- t1/2 (h): ~4h
- clearance: hepatic CYP 3A4
- SE: headache, dyspepsia, nasal congestion, blue vision (PDE-6)
- Patients must be stable, intiate this at LOWEST recommended dose
PDE inhibitor selectivity
- PDE5 -> corpus cavernosum
- PDE6 ~ 10 fold -> retina (sildenafil, Varfenafil) —> AE: BLUE VISION DISTURBANCE
- PDE1 ~ 80 fold -> vasculature, heart, brain —> little clinical sig
- PDE11 ~ 800 fold -> heart, pituitary, testes —> negligible
- PDE3 ~ 4000 fold -> heart —> negligible
PDE-5 inhibitor plus what is contraindicated?
Organic nitrates (glyceryl trinitrate) –> extreme hypotension
