Hydrochlorothiazide
Chemical
Thiazide diuretic
Use
- Heart failure
- 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