Nurses Compass
Drug Guide
Penicillamine
Classification
Therapeutic: Antirheumatic, Chelating agent
Pharmacological: D-penicillamine, a thiol compound
FDA Approved Indications
- Rheumatoid arthritis (especially severe cases)
- Wilson's disease (copper overload)
- Cystinuria (to prevent kidney stones)
Mechanism of Action
Penicillamine chelates heavy metals like copper, leading to their excretion. It also modulates immune responses in rheumatoid arthritis by affecting immune complex formation and leukocyte function.
Dosage and Administration
Adult: Dependent on condition; typically, 250-1000 mg/day divided doses for Wilson's disease and rheumatoid arthritis.
Pediatric: Dosage determined by weight and condition; consult specific guidelines.
Geriatric: Adjusted carefully due to potential adverse effects.
Renal Impairment: Lower doses often required; monitor closely.
Hepatic Impairment: Use with caution; adjust doses as needed.
Pharmacokinetics
Absorption: Well-absorbed orally
Distribution: Widely distributed in body tissues
Metabolism: Minimal hepatic metabolism
Excretion: Excreted primarily unchanged in urine
Half Life: Approximately 1-2 hours, but varies depending on tissue binding and condition
Contraindications
- History of hypersensitivity to penicillamine or penicillins
- Severe leukopenia or thrombocytopenia
- Lupus erythematosus
Precautions
- Monitor blood counts regularly, especially at initiation.
- Use with caution in pregnant or breastfeeding women; benefits should outweigh risks.
Adverse Reactions - Common
- Rash, pruritus (Common)
- Nausea, vomiting (Common)
- Proteinuria (Common)
Adverse Reactions - Serious
- Bone marrow suppression (leukopenia, thrombocytopenia, aplastic anemia) (Rare but serious)
- Nephritis (Rare)
- Myasthenia gravis exacerbation (Rare)
Drug-Drug Interactions
- D-penicillamine can increase serum levels of penicillins, causing toxicity.
- Concurrent use with Gold compounds may increase risk of adverse effects.
Drug-Food Interactions
- Supplements containing amino acids or minerals may interfere with absorption.
Drug-Herb Interactions
N/ANursing Implications
Assessment: Baseline and periodic blood counts, renal function, urinalysis, and neurological assessments.
Diagnoses:
- Risk of infection due to bone marrow suppression
- Risk of renal impairment
Implementation: Administer on an empty stomach if possible, monitor lab values regularly, educate about signs of adverse effects.
Evaluation: Efficacy in reducing copper levels in Wilson's disease, improved symptoms in rheumatoid arthritis, and prevention of cystine stones.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report signs of bleeding, sore throat, fever, or unusual fatigue.
- Attend regular blood tests as scheduled.
- Use adequate sun protection due to photosensitivity.
Special Considerations
Black Box Warnings:
- Potential for severe blood dyscrasias, including aplastic anemia and agranulocytosis.
- Renal toxicity.
Genetic Factors: Individuals with hepatic cirrhosis are at increased risk for adverse effects.
Lab Test Interference: Can interfere with urine tests for proteins and glucose.
Overdose Management
Signs/Symptoms: Nausea, vomiting, diarrhea, hypotension, shock, and hematological abnormalities.
Treatment: Supportive care; consider chelation therapy with EDTA or penicillamine, and urgent medical consultation.
Storage and Handling
Storage: Store at room temperature, protected from light and moisture.
Stability: Stable under recommended storage conditions.