Drug Guide
Allopurinol Sodium
Classification
Therapeutic: Antigout agent
Pharmacological: Xanthine oxidase inhibitor
FDA Approved Indications
- Gout and hyperuricemia associated with cancer therapy
Mechanism of Action
Inhibits xanthine oxidase, reducing the production of uric acid from hypoxanthine and xanthine, thereby decreasing uric acid levels in the blood and tissues.
Dosage and Administration
Adult: Initial dose usually 300 mg daily, adjusted based on response and uric acid levels.
Pediatric: Use with caution; consult specific pediatric dosing guidelines.
Geriatric: Start at lower doses due to potential renal impairment, monitor closely.
Renal Impairment: Reduce dose according to renal function; frequent monitoring needed.
Hepatic Impairment: Use with caution; no specific dose adjustment established.
Pharmacokinetics
Absorption: Rapidly absorbed after IV administration.
Distribution: Widely distributed; crosses the placenta, minimal CNS penetration.
Metabolism: Metabolized minimally; primarily excreted unchanged.
Excretion: Primarily excreted via the kidneys.
Half Life: Approximately 1-2 hours; longer in renal impairment.
Contraindications
- Hypersensitivity to allopurinol or xenobiotic hypersensitivity reactions.
Precautions
- Monitor for hypersensitivity reactions, especially in patients with renal impairment. Use with caution in patients with liver disease, cardiovascular disease, or those prone to skin reactions.
Adverse Reactions - Common
- Rash, including Stevens-Johnson syndrome (Variable, can be serious)
- Gastrointestinal upset (Common)
Adverse Reactions - Serious
- Allergic skin reactions, eosinophilia, hepatitis (Serious but less common)
- Hepatotoxicity (Rare)
- Hematologic reactions (e.g., aplastic anemia, agranulocytosis) (Rare)
Drug-Drug Interactions
- Azathioprine, mercaptopurine (risk of toxicity increases)
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor uric acid levels, renal and hepatic function before and during therapy. Watch for hypersensitivity reactions.
Diagnoses:
- Risk for hypersensitivity reactions,
- Impaired skin integrity
Implementation: Administer after meals to minimize GI upset. Hydrate adequately. Educate about signs of hypersensitivity.
Evaluation: Maintain target uric acid levels, monitor for adverse reactions.
Patient/Family Teaching
- Take medication as directed.
- Report any signs of rash, fever, or hypersensitivity immediately.
- Maintain adequate hydration.
- Avoid alcohol and certain medications that can increase uric acid levels or interact with allopurinol.
Special Considerations
Black Box Warnings:
- Severe hypotension and skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, especially when administered rapidly or in high doses.
Genetic Factors: Higher risk of severe skin reactions in HLA-B*58:01 allele carriers, particularly in Asian populations.
Lab Test Interference: Can affect renal function tests and uric acid levels.
Overdose Management
Signs/Symptoms: Hypotension, skin reactions, nausea, vomiting.
Treatment: Supportive care, activated charcoal if ingestion recent, and symptomatic treatment. No specific antidote.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable under recommended storage conditions.