Drug Guide
Aminosalicylic Acid
Classification
Therapeutic: Antitubercular agent
Pharmacological: Salicylate
FDA Approved Indications
- Treatment of active tuberculosis, especially multi-drug resistant strains
Mechanism of Action
Inhibits bacterial folic acid synthesis by antagonizing para-aminobenzoic acid (PABA), leading to suppression of bacterial growth
Dosage and Administration
Adult: 250-500 mg orally 3 times daily, adjust based on response and tolerance
Pediatric: Dose based on weight, typically 25-50 mg/kg/day divided into 3 doses
Geriatric: Use with caution; start at lower doses due to potential renal impairment
Renal Impairment: Adjust dosage accordingly; monitor renal function closely
Hepatic Impairment: Use with caution; hepatic function monitoring recommended
Pharmacokinetics
Absorption: Well absorbed orally
Distribution: Distributed throughout body tissues; crosses cerebrospinal fluid
Metabolism: Primarily unchanged; minimal hepatic metabolism
Excretion: Excreted mainly via the kidneys
Half Life: Approximately 3-4 hours
Contraindications
- Hypersensitivity to aminosalicylic acid or salicylates
Precautions
- Renal impairment
- Hepatic impairment
- G6PD deficiency (risk of hemolytic anemia)
- Use with caution in children and the elderly
Adverse Reactions - Common
- Gastrointestinal upset (Common)
- Nausea (Common)
- Loss of appetite (Common)
Adverse Reactions - Serious
- Hemolytic anemia (Rare)
- Hypersensitivity reactions (e.g., rash, fever) (Rare)
- Salicylate toxicity (e.g., tinnitus, vertigo) (Rare)
Drug-Drug Interactions
- Other salicylates or NSAIDs (increased risk of bleeding and salicylate toxicity)
- Methotrexate (increased toxicity)
- Warfarin (increased bleeding risk)
Drug-Food Interactions
- Alcohol (increased risk of gastrointestinal bleeding and salicylate toxicity)
Drug-Herb Interactions
- Ginger, ginkgo (may increase bleeding risk)
Nursing Implications
Assessment: Monitor for signs of salicylate toxicity, renal function, and complete blood counts
Diagnoses:
- Risk for bleeding
- Risk for impaired renal function
Implementation: Administer with food to reduce gastrointestinal upset; monitor labs periodically
Evaluation: Therapeutic response (e.g., sputum conversion in TB), monitor for adverse reactions
Patient/Family Teaching
- Take medication exactly as prescribed; do not overdose
- Report signs of salicylate toxicity such as tinnitus, vertigo, or hearing loss
- Use caution with alcohol and other NSAIDs
- Maintain adequate hydration
- Follow-up appointments for lab monitoring
Special Considerations
Black Box Warnings:
- Use with caution due to potential for salicylate toxicity
Genetic Factors: G6PD deficiency increases risk of hemolytic anemia
Lab Test Interference: May cause false-positive urine glucose tests
Overdose Management
Signs/Symptoms: Tinnitus, vomiting, hyperventilation, dehydration, seizures
Treatment: Supportive care, gastric lavage if recent ingestion, activated charcoal, hemodialysis in severe cases
Storage and Handling
Storage: Store at room temperature, protected from moisture and light
Stability: Stable under proper storage conditions