Penicillamine is approved by the FDA as a treatment for Wilson disease and cystinuria. It also is used as an off-label treatment option for lead poisoning in children.
Penicillamine can chelate heavy metals such as lead, copper, and mercury and form a soluble complex that is renally excreted in the urine. It also can combine and form disulfide bonds with cysteine and facilitates the excretion in urine. This helps to prevent the formation of cystine calculi.
In rheumatoid arthritis, it is known to depress T cell activity.
It has a plasma peak time of 1 to 3 hours and a peak plasma concentration of 1 to 2 mg/L for the 250 mg dose. More than 80% is protein bound, and it is excreted in the urine.
It usually exists as 250 mg tablets and 125 mg or 250 mg capsules.
Penicillamine should be taken at least 1 hour before meals or 2 hours after meals. Some protocols recommend taking the drug at least 2 hours before meals in cases of lead poisoning. It is also advised to take the drug at least 1 hour apart from other drugs or zinc-containing products and if the patient is consuming milk or antacids. It is highly recommended to supplement the patient with pyridoxine. In patients with Wilson disease, 25 to 50 mg/day of pyridoxine is advised. A multivitamin regimen without copper can also be added. In patients with rheumatoid arthritis or cystinuria, it is recommended to take 25 mg of pyridoxine per day. The last dose of the day should be taken at least 3 hours after dinner.
Most Common Adverse Effects
Less Common Adverse Effects
Rare Adverse Effects
Penicillamine is contraindicated in the following conditions:
Breastfeeding: Presence of the drug in breast milk is unknown and not documented. There is a manufacturers advice against breastfeeding.
Given the adverse effects, it is recommended to monitor and watch out for the following:
The drug should be used with caution in the elderly as they are more at risk to develop a skin rash and gastrointestinal side effects.
Penicillamine also interacts with the following drugs:
The following drugs decrease the levels of penicillamine:
The following drugs increase levels of penicillamine:
During the first month of therapy, it is advised to check the blood cell levels with a complete blood count, platelet count, and urinalysis as well as to properly monitor for any changes in the skin, lymph nodes, and body temperature twice weekly. From the second month until the fifth month, the laboratory and physical findings should be investigated every 2 weeks, and from sixth month onwards it should be tested on a monthly basis.
Patients should be advised to report any symptoms suggesting toxicity such as fever, bleeding, bruising, and chills. Gold sodium thiomalate can cause toxicity of penicillamine and should be avoided.