Penicillamine

Penicillamine In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Penicillamine is an orally administered chelating agent that binds copper, mercury and lead.
• It also binds to cystine.

Uses of Penicillamine

• Management of copper storage disease in Bedlington Terriers and copper-associated hepatopathy in other susceptible breeds.
• Penicillamine is not effective in acute crises due to the slow process of copper chelation, which takes weeks to months.
• Cystinuria treatment: Penicillamine is used to decrease cystine excretion by forming a soluble complex, cystine-D-penicillamine disulphide.
• Management of lead toxicity: Penicillamine may be used when injecting EDTA is challenging or when long-term chelation is necessary.

Dose of Penicillamine in Dogs and Cats

Dogs:

• Copper storage disease and copper-associated hepatitis: 10 mg/kg p.o. q12h given on an empty stomach at least 1 hour before feeding.
• Cystinuria: 10–15 mg/kg p.o. q12h.
• Lead poisoning: patients commonly receive CaEDTA before receiving penicillamine 30 minutes before feeding at 30 mg/kg p.o. q6–8h for 1–2 weeks.
• The dose may then be reduced to 5 mg/kg p.o. q6–8h if serum lead levels remain high despite the resolution of clinical signs.

Cats:

• Lead poisoning: patients commonly receive CaEDTA before receiving penicillamine 30 minutes before feeding at 15 mg/kg p.o. q6–8h for 1 week.
• The dose may then be reduced to 5 mg/kg p.o. q6–8h if serum lead levels remain high despite the resolution of clinical signs.

Side Effects of Penicillamine in Dogs and Cats

• Anorexia, vomiting, pyrexia, and nephrotic syndrome are seen in dogs.
• Serious adverse effects described in humans given penicillamine include leucopenia, thrombocytopenia, fever, lymphadenopathy, skin hypersensitivity reactions, and lupus-like reactions.
• Weekly initial monitoring, including a full blood count and urinalysis, is advised for dogs.
• Allergic reactions in humans to penicillin may have similar reactions to penicillamine, but cross-sensitivity seems to be rare.

Contraindications of Penicillamine in Dogs and Cats

• Moderate to marked renal impairment and a history of penicillamine-related blood dyscrasias.
• Penicillamine can reduce gastrointestinal absorption of dietary minerals, including
  zinc, iron, copper and calcium and, therefore, cause deficiencies with long-term use.

Some Notes:

• The absorption of penicillamine is decreased if administered with antacids, food, or iron or zinc salts.
• An increase in the renal and haematological effects of penicillamine have been
  recorded in humans receiving it with cytotoxic drugs.
• Concomitant use of NSAIDs and other nephrotoxic drugs may increase the risk of
  renal damage.