Urology Drugs

Question 1

Name a xanthine oxidase inhibitors

Answer 1

Allopurnol

Question 2

Indications of xanthine oxidase inhibitors

Answer 2

1) gout - prevents acute attacks
2) Prevents renal stones –> rpevents uric acid and calcium oxalate stones
3) Prevents hyperuricaemia and tumour lysis syndrome

Question 3

Action of xanthine oxidase inhibitors

Answer 3

Inhibits xanthine oxidase
This enzyme metabolises xanthine (produced from purines) to uric acid
Hence inhibition loweres the plasma uric acid concentration –> so less precipitates in the joints/kidneys

Question 4

Advesrse effects of xanthine oxidase inhibitors

Answer 4

1) Skin rash - most common
2) Drug hypersensitiviy reaction
3) Starting the drug can trigger or worsen an acute attack of gout

Question 5

Warning of using allopurinol

Answer 5

Dont start during an acute attack - but can be continued if patient is already esatblished on it

Dose reduction in renal/hepatic impairment - metabolised in liver and excreted by the kidney

Question 6

Contraindication of allopurinol

Answer 6

Recurrent skin rash

Severe hypersensitivity

Question 7

Interactions of allopurinol

Answer 7

1) Mercaptopurine (cytotoxic) and its pro-drug azothiporine –> these drugs require xanthine oxidase for metbaolism hence allopurinol causes increased risk of toxicity
2) Co-precription with amoxicillin - icnreased change of amoxocillin
4) Co-prescription with ACEi and thiazides –> increased risk of hypersensitivity

Question 8

Name alpha-blokcers

Answer 8

Doxasozin
Tamsulosin
Alfuzosin

Question 9

Indcations of alpha-blockers§

Answer 9

1) BPH - 1st line

2) Add on treatment in resistant hypertenstion - when other medicines are insufficient

Question 10

Action of alpha-blockers

Answer 10

Most are highly selective for alpha 1 recptor –> mainly in smooth muscle, blood vessles and urinary tract

Blcokage = relaxation –> hence causes vasodilation, reduced resistance to bladder outflow

Question 11

Adverse effects of alpha blockers

Answer 11

postural hypotension
Dizziness
syncope

PARTICULARLY PROMINENt AFTER FIRst DOSE - warn patient

Question 12

Contraindications of alpha blockers

Answer 12

Avoid in patient with existing postural hypotension

Question 13

Interactions of alphablcokers

Answer 13

Additive effect to lower blood pressure
Avoid pronounced first dose hypotension by omitting one or more of the existing anti-hyperetsnives on the day the alpha blocker is started

Particularly the case for beta blockers as these inhibit reflex tachycardia that is part of the compensatory response for vasodilatation

Question 14

When should you take alphablockers

Answer 14

Take at bedtime due to blood pressure effect

Question 15

Name 5-alpha reductase inhibitors

Answer 15

Finasteride

Question 16

Indications of finasteride

Answer 16

1) BPH - 2nd line treatment

Question 17

What is first and second line treatment of BPH

Answer 17

1st line - Doxasozin

2nd line - Finasteride

Question 18

Action of finasteride

Answer 18

Inhibits intracellular enzyme 5-alpha reductase
This enzyme converts testosterone to dihydrotestosterone (more active)
Dihydrotestosterone stimualtes prostatic growth –> inhibit it to reduce prostate enlargement and improve urinary flow

Question 19

How long does it take for finasteride to work

Answer 19

Takes several motsh for its effect to become evident

Hence alpha blockeres are preferred for initial therapy with 5-alpha reductase inhibitors

Question 20

Adverse effects of finasteride

Answer 20

Anti-androgen activity –> e.g. impotence, reduced libido, breast tenderness and gynaecomastia

hair growth

Breast cancer

Question 21

Warnings of finasteride

Answer 21

CI in pregnant women

They shouldnt hold broken/damaged tablet or throguh tht semen of men taking the tablet

This causes abrnormal development of the male external gentialia

Question 22

INteractions of finasteride

Answer 22

No clinically important interactions