GU

Question 1

Oxybutynin / Solifenacin / Tolterodine

Anti-muscarinic agents

Answer 1

Bind to the muscarinic receptor where they act as competitive inhibitors of acetylcholine which blocks contraction of smooth muscle => Promoting bladder relaxation => Increasing bladder capacity, hence, less frequency of urination (Relatively M3 selective)

Question 2

Alfuzosin / Doxazosin / Tamsulosin

a-blockers

Answer 2

a1-adrenoreceptors (found in smooth muscle of vessels and urinary tract) - blocked which induced relaxation
Cause vasodilatation which reduces BP and reduces resistance to bladder outflow

Question 3

Dutasteride / Finasteride

5a-reductase inhibitors

Answer 3

Inhibit the enzyme converting testosterone to dihydrotestosterone which is a more active metabolite and usually what stimulates prostatic growth => hence, inhibition reduces gland size and helps urine passing

Question 4

Sildenafil/Tadalafil

5-Phosphodiasterase Inhibitors

Answer 4

Increase blood flow to the penile region but do not initiate an erection - hence sexual stimulation still needed. PDE5 is responsible for the breakdown of
cGMP, inhibition of this enzyme by sildenafil increases cGMP
concentrations, improving penile blood flow and erection quality.

Question 5

Oestrogen/Progestogen (Contraceptives)

Answer 5

Luteinising hormone (LH) and follicle-stimulating hormone (FSH) control
ovulation and ovarian production of oestrogen and progesterone. In turn,
oestrogen and progesterone exert predominantly negative feedback on
LH and FSH release. In hormonal contraception, an oestrogen (e.g.
ethinylestradiol) and/or a progestogen (e.g. desogestrel) are given to
suppress LH/FSH release and hence ovulation. Oestrogens and
progestogens also have many effects outside the ovary. Some, such as
those on the cervix and endometrium, may contribute to their
contraceptive effect (this is especially important in progestogen-only
contraception). Others offer additional benefits, e.g. reduced menstrual
pain and bleeding, and improvements in acne. At the menopause, a fall in
oestrogen and progesterone levels may generate a variety of symptoms,
including vaginal dryness and vasomotor instability (‘hot flushes’).
Oestrogen replacement (usually with a progestogen) alleviates these.