Diuresis
Reversible, non-competitive inhibitor of carbonic anhydrase
PCT: ↓H+ and HCO3- prodn
↓ cytosol H+ → ↓Na+ reabs in PCT→ ↑H2O loss
↓cytosol HCO3→↑luminal HCO3→ H2O diffusion with HCO3 ,Na, K to urine
Eye: ↓Na pump, ↓AH formation

Diuresis
Inhibition of active chloride ion reabsorption in PCT and ascending limb of LoH
↓ reabsorption of NaCl → ↓ tonicity in the renal medulla → ↓water reabsorption and diuresis.
Other effects are mediated by the induction of the COX-2 enzyme which assists in synthesis of prostaglandins.

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

Metabolic: Acidosis via ↑ excretion of bicarb (and reabsorption of Cl)
Resp: ↑MV → comp resp alk
CNS: anticonvulsant properties, ↓ CSF and IOP by ↓d formation GIT: ↓ Pancreatic and gastric
GU: mild diuresis, Na retention

Pulmonary and systemic vasodilation
Diuresis ↑ RBF and ↑ corticomedullary blood flow
↓O₂ demand in the LoH (ischaemic
protection)

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

IV/PO
PO BA = 100%

PO/IV/SL/IM. PO BA 50% Onset PO/SL 30-60mins, IV 5 mins .
Dur PO/SL 6-8hrs, IV 2hrs

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

Lip sol: crosses BBB

70-90%

91-99% (Albumin)

68%

0.1L/kg

3.6-7.8L/kg

Not metabolised

Renal to glucuronide
Minimal hepatic

Not metabolized

Unchanged in urine

80% unchanged in urine

Urine (unchanged)

6-9hrs

0.5-2hrs. ESRF: 9hrs

5.6-14.8hrs

metabolic acidosis, urinary alkalinisation, parathesias, fatigue,
hypokalaemia, N+V, abdo pain

Tox: Rashes, renal stones

↓ K+/Na+/Cl-/Ca++, Hyper- urea/glu/chol, Metabolic alkalosis
Tox: Deafness, Pancreatitis
BM depression
Interstitial nephritis (worse with aminoglycoside)

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

Diuretic – Carbonic Anhydrase Inhibitor

Diuretic - Loop

Diuretic - Thiazide

Glaucoma
Miniere’s disease
Altitude sickness
Adjunct in epilepsy

Oedema of cardiac, renal or hepatic origin, Renal insufficency
Hypertension
Raised ICP
Hypercalcaemia

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

Sulfonamide

Sulfonamide derivative

related to the sulphonamides

Level 3

Level 1

Level 3

250mg white tablets
500mg vials for reconstitution

Photosensitive solution 10mg/ml
20/40/500mg tabs, Syrup

orange scored tablets of 25mg and combos

250-1000mg q6hrly
IV/PO

20-2000mg daily
PO/IV/SL/IM.

PO. 12.5-200mg/day