GU DRUGS

Question 1

Alpha Blockers

Tamsulosin, Doxazosin, Alfuzosin

Answer 1

I: BPH, resistant hypertension
MOA: causes vasodilation in BP and a reduced resistance to bladder outflow in BPH
SE: Postural hypotension, dizziness and syncope (first dose)
CI: existing postural hypotension
KI: omit doses of 1 or more existing HTN drugs on the day the alpha blocker is commenced to reduce risk of first dose hypotension.
Avoid in cataract surgery
PC: may cause dizziness on standing particularly after 1st dose.
Take the medication at bedtime to minimise impact and when they need to get up at night, they should rise from the bed slowly.
M: symptom enquiry and measure sitting + standing BP

Question 2

5a reductive inhibitor

Finasteride

Answer 2

I: BPH
SE: Impotence, reduced libido, breast tenderness/ enlargement, hair growth. Breast cancer in men taking finasteride
CI: pregnant women due to abnormal development of external genitalia in male foetuses
PC: Reduce bulk of prostate gland
Easier to pass urine
May take up to 6 months for symptoms to improve
May feel less keen to have sex + get or keep an erection. (Short while only and normal function continues as treatment continues)
SAFETYNET: If he notices tenderness of growth of the breast to come back.
If partner has a partner who is or could get pregnant, advise him that she is exposed to the drug that can harm the baby.
They should use condoms

Question 3

Antimuscaranics

Oxybutynin, Tolterodine, Solifenacin

Answer 3

I: Overactive bladder
MOA: competitive inhibitor of acetylcholine. It promotes bladder relaxation, reduces urinary frequency, urgency and urge incontinence. Helps through antagonism of the M3 receptor.
SE: dry mouth, tachycardia, constipation and blurred vision
CI: UTIs
C: Angle closure glaucoma, arrhythmias, urinary retention, elderly, dementia
KI: Tricylic antidepressants e.g Amitriptyline can increase risk of side effects.
PC: dry mouth is a very common SE
In elderly pts, the medication can cause drowsiness and confusion and stop taking it if it occurs
M: 1/12 follow up symptom enquiry

Question 4

Phosphodiestrase type 5 inhibitors

Sildenafil

Answer 4

I: Erectile dysfunction, Primary pulmonary hypertension
MOA: selective for PDE type 5 found in the smooth muscle of the penis and arteries of the lung. Increases cGMP concentrations, improves penile blood flow and erection quality.
SE: Flushing, headache, dizziness , nasal congestion, blue tinge in eyes
Serious SE: Hypotension, tachycardia and palpitations
Risk of vascular events
Priapism (erection does not subside) and visual disorders (colour distortion)
CI: Stroke, ACS, CVD. Pts on nitrates or nicorandil
C: hepatic or renal impairment. Pts should not take vasodilators e.g alpha blockers and CCBs within 4 hours of sildenafil due to increased risk of hypotension.
KI: CYP inhibitors (amiodarone, macrolides, diltiazem) can increase effects of sildenafil.
PC: Drug will not produce erection without sexual stimulation.
Take an hour before sex to allow time for absorption.
SAFETYNET: If erection does not subside within 2 hours of sexual activity, seek medical advice
Report eyesight changes