Generic Name

Colchicine

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Classification

FDA Approved Indications

• Gout flares
• Familial Mediterranean fever

Mechanism of Action

Colchicine disrupts microtubule polymerization by binding to tubulin, reducing leukocyte migration and activity, leading to decreased inflammation in gout.

Dosage and Administration

Adult: Dosage varies based on indication; typical initial dose for gout is 1.2 mg followed by 0.6 mg one hour later, then maintenance doses of 0.6 mg once or twice daily.

Pediatric: Use is generally not recommended due to limited safety data.

Geriatric: Use with caution; start at lower doses and monitor closely.

Renal Impairment: Dose adjustments are necessary; see prescribing information.

Hepatic Impairment: No specific adjustment recommended; use with caution.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Widely distributed, enters cells and tissues.

Metabolism: Metabolized minimally in the liver.

Excretion: Primarily via renal pathway, also fecal.

Half Life: Approximately 27-30 hours.

Contraindications

• Severe renal or hepatic impairment
• Hypersensitivity to colchicine

Precautions

• Risk of toxicity in patients with renal or hepatic impairment
• Use cautiously with drugs that inhibit CYP3A4 or P-glycoprotein

Adverse Reactions - Common

• Gastrointestinal symptoms (nausea, vomiting, diarrhea) (Common)
• Myelosuppression (Uncommon)

Adverse Reactions - Serious

• Muscle toxicity (myopathy) (Rare)
• Bone marrow suppression (Rare)
• Multi-organ failure (Rare)

Drug-Drug Interactions

• CYP3A4 inhibitors (e.g., clarithromycin, ketoconazole)
• P-glycoprotein inhibitors

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Report any unusual muscle pain, weakness, or gastrointestinal symptoms.
• Avoid grapefruit juice and other CYP3A4 inhibitors during therapy.
• Maintain hydration during therapy.

Special Considerations

Black Box Warnings:

• Potential for serious toxicity, including myelosuppression and multi-organ failure, especially when combined with CYP3A4 inhibitors or in renal impairment.

Genetic Factors: Limited data; pharmacogenomic testing not routinely recommended.

Lab Test Interference: May cause false elevations of uric acid in some assays.

Overdose Management

Signs/Symptoms: Severe gastrointestinal symptoms, bone marrow suppression, multiorgan failure.

Treatment: Supportive care; activated charcoal if ingestion is recent; hemodialysis may be considered in severe renal impairment.

Storage and Handling

Storage: Store at room temperature away from moisture and light.

Stability: Stable for the duration of the labeled shelf life.