Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CHEMET vs DEPEN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Chelates heavy metals, particularly lead, mercury, and arsenic, by forming soluble complexes that are excreted renally. Acts as an antidote by binding to toxic metals and reducing their tissue concentrations.
Penicillamine is a chelating agent that forms soluble complexes with heavy metals (e.g., copper, mercury, lead) and promotes their renal excretion. In rheumatoid arthritis, it reduces rheumatoid factor and immune complexes, and inhibits collagen cross-linking.
Treatment of acute and chronic lead poisoning,Treatment of mercury poisoning,Treatment of arsenic poisoning,Diagnostic chelation challenge test
Wilson's disease,Cystinuria,Rheumatoid arthritis,Heavy metal poisoning (e.g., lead, mercury)
10-20 mg/kg orally every 8 hours for 5 days; maximum single dose 1250 mg.
250 mg orally 4 times daily, target dose 1000-1500 mg/day in divided doses.
Terminal elimination half-life: 1.6–3.5 hours (mean 2.1 h) in adults with normal renal function; prolonged in renal impairment (up to 20 h).
1.5-4 hours; prolonged to 6-12 hours in renal impairment; clinical context: dosing interval adjustments needed in CKD.
Metabolized in liver to disulfide dimers; undergoes enterohepatic circulation; primarily excreted renally as metabolites and unchanged drug.
Penicillamine is metabolized via oxidation to disulfides. It is primarily excreted in urine as unchanged drug and metabolites.
Renal: 80–90% as unchanged drug and metabolites (primarily as chelated complexes); biliary/fecal: <10%.
Renal: 50% as unchanged drug; biliary/fecal: minor, <5%.
Approximately 80% bound to plasma proteins, primarily albumin.
80%; primarily to albumin.
0.5–0.8 L/kg, indicating distribution mainly in extracellular fluid; limited intracellular penetration.
0.1-0.4 L/kg; indicates limited extravascular distribution, mainly confined to plasma and interstitial fluid.
20–40% after oral administration due to first-pass metabolism and limited absorption.
Oral: 40-70% (variable due to food and formulation).
GFR 50-80 m L/min: same dose every 12 hours. GFR 10-49 m L/min: same dose every 24 hours. GFR <10 m L/min: same dose every 48 hours.
GFR 30-59 m L/min: 250 mg every 8-12 hours; GFR 15-29 m L/min: 250 mg every 12-24 hours; GFR <15 m L/min: 250 mg every 24 hours or avoid use.
No specific recommendations; caution in severe hepatic impairment (Child-Pugh C) due to potential toxicity.
No adjustment recommended for mild to moderate impairment (Child-Pugh A or B); avoid use in severe impairment (Child-Pugh C) due to increased risk of hepatotoxicity.
Children >1 year: 10-20 mg/kg/dose orally every 8 hours for 5 days; maximum 1250 mg/dose.
Children >1 year: 10-15 mg/kg/day divided every 6-8 hours, maximum 500 mg/day.
Consider starting at lower end of dosing range (10 mg/kg) due to potential renal impairment; adjust per renal function.
Start at lower end of dosing range (250 mg twice daily) due to age-related renal function decline; monitor renal function and adjust based on creatinine clearance.
None
None.
May cause nephrotoxicity; monitor renal function,May cause hypersensitivity reactions, including fever, rash, and anaphylaxis,Monitor for neutropenia; obtain CBC before and during therapy,Use caution in patients with hepatic impairment or glucose-6-phosphate dehydrogenase (G6PD) deficiency,May chelate essential minerals (e.g., zinc, copper); monitor levels with prolonged use,Not recommended for routine use in asymptomatic lead poisoning with low blood lead levels
Bone marrow suppression (leukopenia, thrombocytopenia, aplastic anemia),Proteinuria and nephrotic syndrome,Autoimmune reactions (lupus-like syndrome, myasthenia gravis),Hepatotoxicity,Severe skin reactions (e.g., pemphigus, Stevens-Johnson syndrome),Monitor renal function, blood counts, and urinalysis regularly
Hypersensitivity to dimercaprol or any component of the formulation,Hepatic failure (except severe heavy metal poisoning),Concurrent use with iron (increases nephrotoxicity); avoid iron therapy within 24 hours,Pregnancy (if not life-saving indication due to risk of teratogenicity),Peanut allergy (formulation contains peanut oil)
History of penicillamine-induced aplastic anemia or agranulocytosis,Pregnancy (relative contraindication due to teratogenicity),Renal insufficiency (avoid in severe impairment),Hypersensitivity to penicillamine
No specific food interactions reported. However, due to gastrointestinal side effects (nausea, vomiting), it is advisable to maintain small, frequent meals. Avoid alcohol.
Avoid foods high in copper (e.g., liver, shellfish, nuts, chocolate, mushrooms) during treatment for Wilson disease. For cystinuria, maintain high fluid intake (at least 3-4 liters/day) and reduce sodium and animal protein to decrease cystine excretion. Vitamin B6 supplementation may be needed as DEPEN can increase pyridoxine requirements.
FDA Pregnancy Category C. First trimester: No adequate studies, but animal studies show fetal resorption at maternally toxic doses, risk cannot be excluded. Second and third trimesters: No specific teratogenicity, but may cause anemia in fetus due to maternal chelation of essential metals. Avoid use unless clearly needed.
Penicillamine (Depen) is associated with severe fetal malformations including cutis laxa and skeletal abnormalities when used during pregnancy. First trimester exposure carries highest risk; use is contraindicated unless necessary for maternal conditions like Wilson's disease or cystinuria. Second and third trimester use may cause fetal connective tissue disorders.
No human data on excretion in breast milk. M/P ratio unknown. Caution due to potential for infant exposure and chelation of trace elements; consider benefit-risk. Avoid breastfeeding during therapy and for 2 weeks after last dose.
Penicillamine is excreted into breast milk in low amounts; M/P ratio not well defined. Potential for infant toxicity (e.g., rash, bone marrow suppression). Caution advised; monitor infant for adverse effects. Alternative therapies preferred.
No specific dose adjustments recommended for pregnancy. Increased plasma volume in pregnancy may alter pharmacokinetics, but studies not performed. Use lowest effective dose; monitor therapeutic response and toxicity closely.
No standard dose adjustment defined; use lowest effective dose. Pharmacokinetics not well studied; increased clearance may require dose titration. Monitor clinical response and copper levels in Wilson's disease.
Chelation therapy with dimercaprol (CHEMET) should be initiated within 4 hours of arsenic or mercury exposure for maximal efficacy. Administer only via deep intramuscular injection, never intravenously. Monitor renal function and urine output closely, as dimercaprol can cause nephrotoxicity. Alkalinize urine to p H 7.5-8.5 to decrease renal precipitation of metal-drug complexes. Use with caution in patients with glucose-6-phosphate dehydrogenase deficiency due to risk of hemolysis. Contraindicated in patients with peanut allergy (vehicle is peanut oil).
DEPEN (penicillamine) is a chelating agent used for Wilson disease, cystinuria, and rheumatoid arthritis. Monitor for proteinuria and hematuria due to immune complex nephropathy. Cross-sensitivity with penicillin possible. Administer on empty stomach for Wilson disease; with meals for cystinuria to reduce GI upset. Avoid concomitant use with other nephrotoxic drugs.
This medication is given as a shot into a muscle, usually in the buttock. It may cause pain at the injection site.,You may experience a metallic taste, nausea, vomiting, headache, or burning sensation in the mouth or throat.,Drink plenty of fluids unless otherwise instructed to help flush metals from your body.,Avoid alcohol during treatment and for at least 48 hours after the last dose.,Report any signs of allergic reaction (rash, itching, difficulty breathing) or dark urine immediately.
Take DEPEN on an empty stomach at least 1 hour before or 2 hours after meals, unless otherwise directed for cystinuria.,Do not skip doses; consistent intake is critical for Wilson disease to prevent copper accumulation.,Report any signs of infection, unusual bleeding, skin rash, or changes in urine color or output immediately.,Avoid alcohol completely as it may increase risk of liver toxicity.,Use effective contraception during therapy as DEPEN can cause fetal harm.,Have regular blood and urine tests as ordered to monitor for side effects.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about CHEMET vs DEPEN, answered by our medical review team.
CHEMET is a Chelating agent that works by Chelates heavy metals, particularly lead, mercury, and arsenic, by forming soluble complexes that are excreted renally. Acts as an antidote by binding to toxic metals and reducing their tissue concentrations.. DEPEN is a Chelating Agent that works by Penicillamine is a chelating agent that forms soluble complexes with heavy metals (e.g., copper, mercury, lead) and promotes their renal excretion. In rheumatoid arthritis, it reduces rheumatoid factor and immune complexes, and inhibits collagen cross-linking.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CHEMET and DEPEN depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of CHEMET is: 10-20 mg/kg orally every 8 hours for 5 days; maximum single dose 1250 mg.. The standard adult dose of DEPEN is: 250 mg orally 4 times daily, target dose 1000-1500 mg/day in divided doses.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between CHEMET and DEPEN in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. CHEMET is classified as Category C. FDA Pregnancy Category C. First trimester: No adequate studies, but animal studies show fetal resorption at maternally toxic doses, risk cannot be excluded. Second and third trimes. DEPEN is classified as Category C. Penicillamine (Depen) is associated with severe fetal malformations including cutis laxa and skeletal abnormalities when used during pregnancy. First trimester exposure carries hig. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.