1 Drug a day :Acetazolamide

28 11 2012

Apologies for the long hiatus —-had bouts of personal problems including a mishap involving a loved one.

I do have a few cases to dissect. My original aims for this blog was to try and do something like what this fella Chris Partyka  (an EM registrar in NSW i think) does i.e. his blog : http://thebluntdissection.com/ 

However before that I have my primaries coming up and its daunting. Only 78 days to go !

I thought i’ll do something different….while am trying to compile cases and lessons I learnt I’ll also revise my drugs so….

…………….presenting ONE DRUG A DAY.

 

Today’s drug—–drumroll please

ACETAZOLAMIDE

with every drug the format will be

1. WHAT IS IT

2. PHARMACODYNAMICS

3. PHARMACOKINETICS

4. CLINICAL INDICATIONs

5. SIDE EFFECTs

 

  • What is it ?

diuretic. sold under trade name Diamox. Carbonic anhydrase inhibitor.

 

  • PHARMACODYNAMICS ?

inhibits carbonic anhydrase (CA) blocking NaHCO3 reabsorption,
where >>> at the Proximal convoluted tubule PCT

What is CA used for ?
see diagram below (photo taken from Katzung)Image

CA does 2 things :

a. Carbonic acid (H2CO3) is rapidly dehydrated by CA to carbon dioxide and water within the lumen
b. the same carbon dioxide and water (within the PCT) is rehydrated by CA to become carbonic acid again

  • PHARMACOKINETICS
    well absorbed orally. Excretion by secretion in proximal tubule S2 segment.

 

  • CLINICAL INDICATIONS
  1. Glaucoma-via reduction in aqueous humor formation
  2. Urinary Alkalinization -increasing urine pH for hyperuricia/cystinueia
  3. Metabolic Alkalosis- esp in CHF patients
  4. Acute Mountain Sickness-decreasing CSF and decreasing pH of CSF/brain : increases ventilation
  5. Others – adjuvants in epilepsy/hypokalaemic periodic paralysis/CSF leak
  • SIDE EFFECTS
  1. Hyperchloremic MEtabolic Acidosis
  2. Renal stones
  3. Renal Potassium Wasting
  4. Drowsiness + parasthesia

Worth watching this :

Youtube video on brief physiology : http://youtu.be/FmKv2qPuB4k

Lifeinthefastlane.com’s critical care manual book by Dr Paul Young : http://lifeinthefastlane.com/book/critical-care-drugs/acetazolamide/


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