Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
BAL vs CHEMET
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Chelating agent that forms stable complexes with heavy metals (e.g., arsenic, mercury, lead) by binding to their sulfhydryl groups, facilitating renal excretion.
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.
Arsenic poisoning,Mercury poisoning,Lead poisoning (adjunct to edetate calcium disodium),Acute gold poisoning,Wilson's disease (investigational)
Treatment of acute and chronic lead poisoning,Treatment of mercury poisoning,Treatment of arsenic poisoning,Diagnostic chelation challenge test
3-5 mg/kg IM every 4 hours for 2 days, then every 6 hours for 1 day, then every 12 hours for 10 days.
10-20 mg/kg orally every 8 hours for 5 days; maximum single dose 1250 mg.
Terminal elimination half-life is approximately 6.8 hours (range 4–13 hours). In patients with impaired renal function, half-life may be prolonged.
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).
Primarily hepatic; undergoes oxidation and conjugation; metabolites excreted renally.
Metabolized in liver to disulfide dimers; undergoes enterohepatic circulation; primarily excreted renally as metabolites and unchanged drug.
Primarily renal; approximately 80% of a dose is excreted in urine as unchanged drug and metabolites within 24 hours. Biliary/fecal elimination accounts for less than 5%.
Renal: 80–90% as unchanged drug and metabolites (primarily as chelated complexes); biliary/fecal: <10%.
BAL is extensively bound to plasma proteins, primarily albumin, with protein binding >90%.
Approximately 80% bound to plasma proteins, primarily albumin.
Volume of distribution is approximately 3.5 L/kg, indicating extensive distribution into tissues, including brain and intracellular spaces.
0.5–0.8 L/kg, indicating distribution mainly in extracellular fluid; limited intracellular penetration.
BAL is not administered orally due to poor absorption and gastrointestinal irritation. Given intravenously, bioavailability is 100%. Intramuscular bioavailability is similar but with slower absorption.
20–40% after oral administration due to first-pass metabolism and limited absorption.
GFR 10-50 m L/min: reduce frequency to every 6-8 hours; GFR <10 m L/min: reduce frequency to every 8-12 hours.
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.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 25%; Child-Pugh C: reduce dose by 50% and monitor for hepatotoxicity.
No specific recommendations; caution in severe hepatic impairment (Child-Pugh C) due to potential toxicity.
3-5 mg/kg IM every 4 hours for 2 days, then every 6 hours for 1 day, then every 12 hours for 10 days; maximum 100 mg per dose.
Children >1 year: 10-20 mg/kg/dose orally every 8 hours for 5 days; maximum 1250 mg/dose.
Start at 3 mg/kg IM every 6 hours; adjust based on renal function, monitor for hypotension and pain at injection site.
Consider starting at lower end of dosing range (10 mg/kg) due to potential renal impairment; adjust per renal function.
None.
None
Monitor renal function and serum electrolytes during therapy.,Can cause hypertension, tachycardia, and myocardial ischemia; use cautiously in cardiovascular disease.,May induce hemolytic anemia in patients with G6PD deficiency.,Injection site reactions and sterile abscesses may occur.,Iron deficiency is a known adverse effect due to iron chelation.
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
Hypersensitivity to BAL or any component.,Hepatic insufficiency (unless benefit outweighs risk).,Iron poisoning (forms toxic complex).,Concurrent use with cadmium or selenium (increased toxicity).
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)
Avoid alcohol and caffeine. Maintain adequate hydration. No specific food restrictions, but ensure iron-rich foods are avoided if concurrent iron poisoning suspected (though BAL not indicated for iron).
No specific food interactions reported. However, due to gastrointestinal side effects (nausea, vomiting), it is advisable to maintain small, frequent meals. Avoid alcohol.
Insufficient human data; animal studies suggest potential teratogenicity at high doses. Avoid in first trimester unless benefit outweighs risk.
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.
BAL (dimercaprol) is excreted into breast milk; M/P ratio unknown. Limited data; exercise caution and consider temporary cessation of breastfeeding during therapy.
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.
No specific dose adjustments recommended in pregnancy; monitor for increased volume of distribution and potential need for higher doses if toxicity persists.
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.
BAL (dimercaprol) is used as a chelating agent for heavy metal poisoning, particularly arsenic, lead, and mercury. Administer deep IM only; avoid IV due to risk of hemolysis. Monitor blood pressure closely as hypertension can occur. Contraindicated in peanut allergy due to peanut oil vehicle. Administer with alkaline urine to protect kidneys.
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).
This medication is given as an injection into a muscle.,You may experience a metallic taste, headache, or nausea.,Report any signs of allergic reaction such as rash or difficulty breathing.,Avoid alcohol while on this medication.,Do not drive or operate heavy machinery until you know how this drug affects you.
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.
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No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about BAL vs CHEMET, answered by our medical review team.
BAL is a Chelating Agent that works by Chelating agent that forms stable complexes with heavy metals (e.g., arsenic, mercury, lead) by binding to their sulfhydryl groups, facilitating renal excretion.. 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.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between BAL and CHEMET 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 BAL is: 3-5 mg/kg IM every 4 hours for 2 days, then every 6 hours for 1 day, then every 12 hours for 10 days.. The standard adult dose of CHEMET is: 10-20 mg/kg orally every 8 hours for 5 days; maximum single dose 1250 mg.. 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 BAL and CHEMET 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. BAL is classified as Category C. Insufficient human data; animal studies suggest potential teratogenicity at high doses. Avoid in first trimester unless benefit outweighs risk.. 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. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.