Colchicine

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Colchicine is specifically used for acute attack of gout. It is not analgesic and relieves pain by controlling inflammation. But has very narrow therapeutic index so fallen out of favor and is hardly available.

Source

Alkaloid obtained from Colchicum autumnale

Mechanism of Action

In acute inflammation for migration and macrophage functions microtubules are required. Polymerization of tubulin occurs. When colchicine binds tubulin, it prevents polymerization. Both chemotactic and phagocytic functions of macrophages are lost, thus

  1.  Controls inflammation and
  2. Rapid proliferation of these inflammatory cells

For cell division, microtubules are required, as are inhibited, thus cell proliferation does not take place.

Colchicine also inhibits leukotrines B4 by unknown mechanism. Thus used for treatment of acute gout.

Pharmacokinetics

Well absorbed orally. Also used I/V.

Dose 0.6 mg initially. 0.6 mg after every two hours, till acute attack subsides. As little as 8 mg can be fatal.

Metabolites are partly excreted through liver, and partly through kidneys.

Side Effects

  1. GIT intolerance –where cells are rapidly dividing, nausea, vomiting, diarrhea, abdominal pain are1st sign of acute toxicity.
  2. Bone marrow suppression
  3. Hair loss
  4. Peripheral neuritis

Acute toxicity

  1. Burning throat pain
  2. Hypotension
  3. Shock
  4. Oliguria leading to hematuria
  5. Ascending CNS paralysis occurs because of respiratory paralysis

Treatment

Only supportive

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The writer enjoys medical education and has special interest in community medicine.