What are the potential side effects of colchicine?

Colchicine Side Effects

Colchicine has numerous potential side effects ranging from common gastrointestinal symptoms to rare but potentially life-threatening multiorgan failure due to its narrow therapeutic index. 1, 2

Common Side Effects

• Gastrointestinal effects (most common):

  • Diarrhea
  • Abdominal pain
  • Nausea and vomiting
  • Hyperperistalsis 1

• Hematologic effects:

  • Neutropenia
  • Thrombocytopenia 1, 3

• Other common side effects:

  • Mild abnormalities in liver enzymes
  • Possible sperm reduction
  • Fatigue/weakness 1, 2

Serious Side Effects

Seek immediate medical attention for:

• Neuromuscular toxicity:

  • Muscle weakness or pain
  • Numbness or tingling in fingers or toes
  • Peripheral neuropathy 1, 2

• Hematologic complications:

  • Unusual bleeding or bruising
  • Increased infections
  • Bone marrow suppression 2

• Other severe manifestations:

  • Pale or gray color to lips, tongue, or palms
  • Severe diarrhea or vomiting
  • Signs of multiorgan failure 2

Risk Factors for Toxicity

Colchicine toxicity risk is significantly increased in:

1. Renal impairment - requires dose reduction starting at 0.3 mg/day in severe cases 1

2. Liver impairment - colchicine undergoes extensive hepatic metabolism 2, 3

3. Drug interactions - particularly with:

   • CYP3A4 inhibitors (clarithromycin, erythromycin, ketoconazole)
   • P-glycoprotein inhibitors (cyclosporine, verapamil)
   • These can increase colchicine levels by 200-300% 1, 3
   • Certain statins may increase risk of myopathy 1, 3

4. Grapefruit juice - should be avoided as it can increase side effect risk 2

Toxicity Phases

Colchicine poisoning typically progresses through three phases:

1. Initial phase (10-24 hours): Gastrointestinal symptoms
2. Second phase (24 hours-7 days): Multi-organ dysfunction
3. Recovery phase: Complete recovery may take weeks 3

Monitoring Recommendations

• Regular assessment every 6 months for patients on long-term therapy
• More frequent monitoring during first year of treatment
• Closer monitoring in patients with renal impairment
• Blood tests may be required during treatment 1, 2

Prevention of Toxicity

• Adhere strictly to prescribed dosage
• Store medication safely away from children
• Avoid unauthorized dose adjustments
• Be aware of potential drug interactions
• Do not take additional doses if symptoms persist 2, 4

Colchicine's narrow therapeutic index means there is little difference between therapeutic and toxic doses, with fatalities reported after ingestions exceeding 0.5 mg/kg and lethal doses as low as 7-26 mg 3. Careful dosing and monitoring are essential to prevent potentially life-threatening toxicity.