Metalcaptase (Penicillamine)

• Metalcaptase (penicillamine) is used in several rare metabolic and autoimmune disorders where metal chelation or immunomodulation is required.
• Wilson disease: chelates excess hepatic and cerebral copper, decreasing tissue accumulation and improving neurological and hepatic symptoms.
• Rheumatoid arthritis: reduces inflammatory joint damage by binding copper and modulating immune pathways, leading to decreased pain and swelling.
• Cystinuria: forms soluble complexes with cystine in urine, lowering stone‑forming cystine concentration and reducing the frequency of kidney stone episodes.

• Penicillamine acts as a high‑affinity chelator that binds copper and other heavy metals, forming stable, excretable complexes. It also reduces disulfide bonds in proteins, which interferes with immune cell activation and decreases inflammatory mediator production. These combined actions lower systemic copper burden and modulate immune responses, providing therapeutic benefit in Wilson disease, rheumatoid arthritis, and cystinuria.

Penicillamine may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea or vomiting: gastrointestinal upset occurring in many patients.
• Diarrhea or abdominal pain: digestive discomfort.
• Skin rash or itching: mild dermatologic reaction.
• Metallic taste or loss of appetite: changes in taste perception.

Serious or Rare Side Effects

• Severe allergic reaction (anaphylaxis): sudden swelling, difficulty breathing.
• Blood dyscrasias (e.g., aplastic anemia, leukopenia): marked reduction in blood cell counts.
• Kidney damage (nephrotic syndrome): protein loss in urine and swelling.

Penicillamine requires careful monitoring and specific safety considerations.

• Renal function: assess baseline kidney function and monitor periodically.
• Hepatic function: evaluate liver enzymes before initiating therapy.
• Autoimmune disorders: use cautiously in patients with systemic lupus erythematosus.
• Pregnancy and lactation: avoid unless benefits outweigh risks.
• Drug monitoring: regular blood counts and urinary copper levels are recommended.
• Store at ambient temperature: keep in original container, protect from moisture and direct sunlight.

Penicillamine can interact with several medicines, necessitating vigilance.

Major Interactions (Avoid)

• Zinc supplements: reduce penicillamine absorption, diminishing efficacy.
• Copper‑containing products: counteract chelation effect.
• Antibiotics such as tetracyclines: may form complexes reducing effectiveness.

Moderate Interactions (Monitor Closely)

• ACE inhibitors: increased risk of hypotension.
• Anticoagulants (warfarin): may enhance anticoagulant effect.
• Thyroid hormones: possible alteration of hormone levels.