Colchicine
Allopurinol (Zyloprim®)

Drug
Colchicine

Dosage used in clinical practice

• 0.6 to 1.2 mg po daily (in single or bid dosage)
• Also available for IV use in special need cases

Dosage according to CPS

• Initial dose: 1 or 1.2 mg followed by 0.5 or 0.6 mg every 2 hours until pain in relieved or toxic symptoms appear
• Total dose required to alleviate an attack: 4 to 8 mg
• Can also be dosed 1.2 mg orally every 12 hours for a maximum of 3 doses

Indications

• Gout
  

Comments
Toxicities associated with colchicine are nausea and vomiting, and diarrhea. Marrow suppression may be seen with increased dosage or prolonged administration of drug.

The incorrect use of colchicine, particularly in the intravenous form, can result in serious toxicity and even death. All reported cases of toxicity, death and neuromuscular disease have been because of unusually high doses, renal insufficiency, age, or the use of both oral and intravenous preparations in a short time period.

Absolute contraindications for colchicine are combined renal and hepatic disease, a glomerular filtration rate of <10 mL/min and extrahepatic bilary obstruction.

Dosage used in clinical practice
100 to 300 mg po daily (in divided doses)

• Minimum effective dose: 100 to 200 mg/day po
• Mild gout: 200 to 300 mg/day po
• Moderately severe tophaceous gout: 400 to 600 mg/day po
• Severe conditions: 700 to 800 mg/day po

Comments
Allopurinol is specifically indicated for gout when serum uric acid is significantly elevated and the frequency or severity of attacks is great, or when tophi are present.

Allopurinol should not be initiated during an acute attack of gout. Once the attack has subsided, allopurinol may be introduced gradually. It is often introduced with an additional prophylactic, either an NSAID or colchicine.

Toxicities associated with allopurinol are skin reactions and rarely blood dyscrasias.