Spiranolactone

Question 1

Class of drug?

Answer 1

Potassium sparing diuretic

Question 2

MOA

Answer 2

Blocks the aldosterone production, so it cannot act on the receptor. In DCT and CD
This inhibits ENaC and Na-KATPase channels.
Spares potassium, can leave through ROMK channels

Question 3

Drug-drug interactions

Answer 3

Amiloride
Alcohol
ACEi
ARBs

Question 4

Adverse side effects?

Answer 4

Gynaecomastia- inc conversion of testosterone to oestradiol due to inc androgen activity. More oestrogen= breast tissue grows
Particularly upsetting to some male patients
Hyperkalaemia- as Na-K-ATPase channel and ENaC inhibited less efflux of K despite potassium sparing. The conc gradient doesn’t favour the movement of K out, so there is a build up of plasma potassium
Severe cutaneous adverse reactions (SCARs)