Antigout agents

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Antigout agents — Antigout; Xanthine oxidase inhibitors (allopurinol, febuxostat), anti-inflammatory antimitotic (colchicine), uricosuric (probenecid).

Identification

• Therapeutic class: Antigout.
• Pharmacologic class: Xanthine oxidase inhibitors (allopurinol, febuxostat), anti-inflammatory antimitotic (colchicine), uricosuric (probenecid).

Pharmacology

• Mechanism of action: Allopurinol and febuxostat reduce uric acid production; colchicine reduces inflammatory response to urate crystals; probenecid increases uric acid excretion.
• Onset / peak / duration: Allopurinol lowers urate over days to weeks; colchicine acts within hours on acute flares.
• Half-life / therapeutic level: Varies; no routine level.

Clinical use

• Indications: Chronic gout and hyperuricemia prevention (allopurinol, febuxostat, probenecid), acute gout flares and prophylaxis (colchicine), tumor lysis prevention (allopurinol).
• Usual dose, route, frequency: Allopurinol PO daily; colchicine PO for flares and low-dose prophylaxis.
• Maximum dose / adjustments: Reduce allopurinol and colchicine in renal impairment; do not start urate-lowering therapy during an acute flare (can worsen it).

Safety

• Contraindications: Colchicine with strong CYP3A4 or P-gp inhibitors in renal or hepatic impairment (toxicity); hypersensitivity.
• Black box warning: None.
• Interactions: Allopurinol with azathioprine and mercaptopurine (severe toxicity), warfarin; colchicine with clarithromycin and other CYP3A4 or P-gp inhibitors (fatal toxicity), statins; probenecid with many renally cleared drugs.
• Pregnancy / lactation: Use only if clearly needed.
• High-alert: No.

Adverse effects

• Common side effects: Allopurinol rash and GI upset; colchicine diarrhea, nausea, cramping.
• Serious effects to report: Allopurinol hypersensitivity and Stevens-Johnson syndrome (linked to HLA-B*5801), colchicine toxicity (severe GI symptoms, myopathy, marrow suppression).
• Antidote / reversal: Supportive care.

Nursing process

• Assessment before administration: Renal and hepatic function, uric acid, current flare status, interacting drugs.
• Interventions during therapy: Do not start allopurinol during an acute attack; encourage fluids; watch for rash.
• Monitor: Uric acid, renal function, CBC (colchicine), skin.
• Evaluation / expected outcome: Fewer gout flares and lower uric acid.

Patient teaching

• Patient teaching: Allopurinol is preventive, not for acute pain; report any rash; drink plenty of fluids; do not exceed colchicine dosing.
• Notify provider if: Rash, severe diarrhea or muscle pain, fever, easy bruising.
• Administration tips: Take allopurinol after meals with fluids; follow colchicine dose limits exactly.