Hydrochlorothiazide

Chemical

Thiazide diuretic

Use

  1. Heart failure
  2. Hypertension

Presentation

25mg PO

Dose

25mg OD – 200mg (in divided doses)

MoA (mechanism)

  • Inhibits Na/Cl cotransporter in DCT
  • ↓Na+ reabsorption
  • DCT is impermeable to H2O
  • 10% filtered Na+ lost

NB: acts in cortex, not medulla ∴ no effect on counter current multiplication

PD

Renal: diuresis

UEC

  • ↑Ca2+ reabsorption
  • K+ loss

PK

A

OBA 70%

D

VD 3.5 – 7.5L/kg

PPB 68%

M

Not metabolised

E

t ½ B 5.5 – 14hrs

Excreted in urine, unchanged

Adverse Effects

Hypokalaemia

Rash

Photosensitivity