dimercaprol
BAL in Oil

Available forms
Available by prescription only
Injection: 100 mg/ml

Indications and dosages
 Severe arsenic or gold poisoning. Adults and children: 3 mg/kg deep I.M. q 4 hours for 2 days and then q.i.d. on day 3. Then b.i.d. for 10 days.
 Mild arsenic or gold poisoning. Adults and children: 2.5 mg/kg deep I.M. q.i.d. for 2 days and then b.i.d. on day 3. Then once daily for 10 days.
 Severe gold dermatitis. Adults and children: 2.5 mg/kg deep I.M. q 4 hours for 2 days and then b.i.d. for 7 days.
 Gold-induced thrombocytopenia. Adults and children: 100 mg deep I.M. b.i.d. for 15 days.
 Mercury poisoning. Adults and children: Initially, 5 mg/kg deep I.M. and then 2.5 mg/kg daily or b.i.d. for 10 days.
 Acute lead encephalopathy or blood lead level above 100 mcg/dl. Adults and children: 4 mg/kg (or 75 to 83 mg/m²) deep I.M. injection, then give simultaneously with edetate calcium disodium (250 mg/m²) q 4 hours for 2 to 7 days. Use separate injection sites.

Pharmacodynamics
Chelating action: The sulfhydryl groups of dimercaprol form heterocyclic ring complexes with heavy metals, particularly arsenic, mercury, and gold, preventing or reversing their binding to body ligands.

Pharmacokinetics
Absorption: Absorbed slowly through the skin.
Distribution: Distributed to all tissues, mainly the intracellular space, with the highest levels of dimercaprol occurring in the liver and kidneys.
Metabolism: Uncomplexed dimercaprol is metabolized rapidly to inactive products.
Excretion: Most dimercaprol-metal complexes and inactive metabolites are excreted in urine and feces.

Contraindications and precautions
Contraindicated in patients with hepatic and renal dysfunction (except postarsenical jaundice), and in iron, cadmium, or selenium poisoning. Use cautiously in patients with hypertension or oliguria. Avoid use in pregnant women unless required to treat a life-threatening acute poisoning. Use cautiously in patients with G-6-PD deficiency because hemolysis may occur.

Interactions
Drug-drug. Cadmium, iron, selenium, uranium: Forms toxic complexes. Delay iron therapy for 24 hours after stopping dimercaprol.

Adverse reactions
CNS: pain or tightness in throat, chest, or hands; headache; paresthesia; muscle pain or weakness, anxiety, fever.
CV: transient increase in blood pressure (returns to normal in 2 hours), tachycardia.
EENT: blepharospasm, conjunctivitis, lacrimation, rhinorrhea, excessive salivation.
GI: nausea; vomiting; burning sensation in lips, mouth, and throat; abdominal pain.
GU: burning sensation in penis.
Skin: pain at injection site,sweating.

Effects on lab test results
None reported.

Overdose and treatment
Signs and symptoms of overdose include vomiting, seizures, stupor, coma, hypertension, and tachycardia; they subside in 1 to 6 hours.
 Support CV and respiratory status; control seizures with diazepam.

Special considerations
 ALERT Administer drug by deep I.M. injection only.
• Treat patient as soon as possible after poisoning for optimal therapeutic effect. Drug is most effective within 2 hours after exposure.
• Adverse effects of dimercaprol are usually mild and transitory and occur in about half of patients who receive an I.M. dose of 5 mg/kg. In patients who receive doses in excess of 5 mg/kg, adverse effects usually occur within 30 minutes after injection and subside in 1 to 6 hours.
• Urinary alkalination is recommended to protect the kidney.
• Dimercaprol therapy blocks thyroid uptake of ¹³¹I, causing decreased values.
Pregnant patients
• Safety in pregnancy hasn’t been established. Don’t use in pregnant women unless needed to treat a life-threatening acute poisoning.
Pediatric patients
• Fever is common, usually appearing after the second or third dose, and may persist throughout therapy.
• Acrodynia in infants and children has been treated with 3 mg/kg of dimercaprol I.M. every 4 hours for 2 days, then every 6 hours for 1 day, followed by every 12 hours for 7 to 8 days.
Geriatric patients
• Use drug cautiously.

Patient education
• Advise patient that drug may cause a bad taste in the mouth or bad breath. It also may cause a burning sensation of the lips, mouth, throat, eyes, and penis, and pain in the teeth.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use