Penicillamine

Indications

Rheumatoid Arthritis

⚠️ Always consult a registered physician before taking any medicine.

Pharmacology

Penicillamine is a chelating agent, which means it helps remove copper and lead from the body. In vitro studies show that one atom of copper combines with two molecules of penicillamine. On that basis, one gram of penicillamine should be followed by the excretion of about 200 milligrams of copper. The amount actually excreted is only about one percent of this. How lead is chelated is not known, though it may be bound in the same way as copper.

Penicillamine also reduces excess cystine excretion in cystinuria. It does this, at least in part, by disulfide interchange between penicillamine and cystine. This forms penicillamine-cysteine disulfide, which is much more soluble than cystine and is excreted readily.

Penicillamine interferes with the formation of cross-links between tropocollagen molecules, and it cleaves them when they are newly formed. In rheumatoid arthritis, the way penicillamine works is unknown, although it appears to suppress disease activity. Unlike cytotoxic immunosuppressants, it markedly lowers IgM rheumatoid factor but does not significantly depress absolute levels of serum immunoglobulins. Cytotoxic immunosuppressants act on both T-cells and B-cells. Penicillamine, in vitro, depresses T-cell activity but not B-cell activity. In vitro, it also dissociates macroglobulins (rheumatoid factor), but how this relates to its effect in rheumatoid arthritis is not known.

Pregnancy & Breastfeeding

Penicillamine was teratogenic in rats when the dose was 6 times higher than the highest dose recommended for humans. Skeletal defects, cleft palates and fetal toxicity (resorptions) were reported. One report describes a woman with rheumatoid arthritis who took less than one gram of penicillamine a day during pregnancy. She gave birth by cesarean delivery to an infant with growth retardation, a flattened face with a broad nasal bridge, low set ears, a short neck with loose skin folds, and unusually lax body skin.

There are no controlled studies of penicillamine in pregnant women. Normal outcomes have been reported, but infants born to mothers who took penicillamine during pregnancy have also had characteristic congenital cutis laxa and related birth defects.

Women of childbearing potential should be given penicillamine only when the expected benefits outweigh the possible hazards. They should be told about this risk while on treatment, and they should be followed closely so that a pregnancy is recognised early.

⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.

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Indications

Pharmacology

Pregnancy & Breastfeeding

Side Effects & Interactions

Side Effects

Key Interactions