Can allopurinol be stopped abruptly?

Abrupt Discontinuation of Allopurinol

Allopurinol can be stopped abruptly without tapering, as there is no evidence that sudden discontinuation causes withdrawal symptoms or worsens gout outcomes. 1

Rationale for Safe Discontinuation

Allopurinol works by inhibiting xanthine oxidase, which reduces uric acid production. When stopped:

• No physiological withdrawal syndrome occurs
• No rebound effect has been documented in guidelines
• The main concern is potential recurrence of gout attacks after discontinuation, not from the abrupt nature of stopping 1

Important Considerations When Stopping Allopurinol

Reasons to discontinue:

• Development of rash or hypersensitivity reaction (requires IMMEDIATE discontinuation) 2
• Pregnancy planning (allopurinol should be stopped before pregnancy) 1
• Severe adverse reactions including:
  • Exfoliative dermatitis
  • Stevens-Johnson syndrome
  • Hepatotoxicity
  • Allopurinol hypersensitivity syndrome (AHS)

Risks after discontinuation:

• Recurrence of gout flares (approximately 40% of successfully treated patients experience flare recurrence after ULT withdrawal) 1
• Return of hyperuricemia
• Potential for tophi reformation

Clinical Guidance After Discontinuation

1. Monitor serum urate levels periodically after discontinuation
2. Watch for gout flare recurrence - especially in the first few months after stopping
3. Consider alternative ULT if allopurinol was stopped due to adverse effects:
   • Febuxostat (if not contraindicated by cardiovascular disease)
   • Uricosuric agents like probenecid (if normal renal function)
   • Benzbromarone (in some countries, for mild-moderate renal impairment) 1

Special Populations and Cautions

• Patients with tophi or frequent attacks: Higher risk of symptom recurrence after discontinuation; may need alternative ULT 1
• Patients with renal disease: Stopping allopurinol may lead to worsening hyperuricemia; monitor closely 1
• Patients on concomitant medications: If patient was on mercaptopurine or azathioprine with dose adjusted for allopurinol, doses may need readjustment when allopurinol is stopped 2

Important Clinical Pitfalls to Avoid

1. Do not restart allopurinol in patients who experienced severe hypersensitivity reactions (AHS) 3
2. Do not confuse flare after discontinuation with a reaction to the medication
3. Do not delay discontinuation if rash or other hypersensitivity signs appear (immediate cessation is required) 2
4. Do not fail to inform patients about the risk of gout flare recurrence after discontinuation

The evidence consistently shows that while long-term ULT is recommended for most gout patients 1, when discontinuation is necessary, it can be done abruptly without concerns about withdrawal effects. The primary consideration is managing the potential return of hyperuricemia and gout symptoms rather than how quickly the medication is stopped.