Core pharmacology

Class Group

Diuretic - Thiazide

Legacy Cicm Level

Level 3

Introduction

related to the sulphonamides

Indications Uses

heart failure and hypertension. Used in combination. mostly bound to plasma prot, and gain access to the tubule via secretion in the PCT.

Presentation

orange scored tablets of 25mg and combos

Mechanism of action

inhibit Na+ reabsorption in the early portion of the distal tubule by
blocking the Na+.Cl- symporter in the apical membrane of these cells. Naturesis
occurs with thiazide diuretics is 5-10% of the filtered load

Physiological effects

Anti-HTN: (↓TPR, ↓plasma volume)
↓RBF → ↓GFR
↓K+,Na+,Mg.
Hyperchloremic MA
↑Ca++ (↓excretion)
↑Glu: (↓glycogenolysis, ↓insulin)

Adverse Effects Toxicity

↓K+/Na+/Mg++, ↑Ca++/urea/glu/chol.
indiosyncratic blood
dyscrasias. Rash, photsensitivity. Interactions may prolong action of NDMBs. NSAIDs antagonise the action

Absorption

PO- BA ~50-80%. Onset 2hrs Dur 6-12hrs.

Protein binding

68%

Volume of distribution

3.6-7.8L/kg

Metabolism

Not metabolized

Excretion

Urine (unchanged)

Half-life

5.6-14.8hrs

Route And Dose

PO. 12.5-200mg/day