Dimercaprol
Dimercaprol (BAL In Oil)
Dimercaprol
(dye-mer- KAP-rohl)
Pregnancy Category: C BAL In Oil (Rx)

Classification: Chelating agent for heavy metals

Action/Kinetics: Forms a chelate by binding sulfhydryl groups with arsenic, mercury, lead, and gold, thus increasing both urinary and fecal excretion of the metals. Because the drug has a higher affinity for the metal than it does for sulfhydryl groups on protein in the body, BAL reverses enzyme inhibition by regenerating free sulfhydryl groups. To be fully effective, administer 1-2 hr after exposure. Peak plasma concentration: IM, 30-60 min. Mostly distributed to extracellular fluid. Time to peak levels: 30-60 min. Rapidly metabolized to inactive product and completely excreted in urine and feces in 4 hr.

Uses: Acute arsenic, mercury, and gold poisoning. With EDTA in acute lead poisoning. Not effective for chronic mercury poisoning.

Contraindications: Iron, cadmium, silver, uranium, or selenium poisoning. Hepatic or renal insufficiency, except postarsenical jaundice.

Special Concerns: Use during pregnancy only if poisoning is life-threatening. Use with caution in clients with G6PD deficiency and during lactation. Of questionable value in bismuth or antimony poisoning.

Side Effects: CV: Most common including hypertension and tachycardia (dose dependent). GI: N&V;, salivation, abdominal pain, burning feeling of the lips, mouth and throat. CNS: Anxiety, weakness, restlessness, headache. Other: Constriction and pain in the throat, chest, or hands; sweating of the hands and forehead, conjunctivitis, blepharal spasm, lacrimation, salivation, rhinorrhea, tingling of hands, burning feeling in the penis, sterile abscesses, local pain at injection site. Children may also develop fever. At high doses dimercaprol may cause coma or convulsions and metabolic acidosis.

Laboratory Test Alterations: Iodine-131 thyroidal uptake during and immediately after dimercaprol therapy.

Overdose Management: Symptoms: Doses exceeding 5 mg/kg usually result in vomiting, convulsions, and stupor. Treatment: Reduce dose; symptoms usually subside within 6 hr.

Drug Interactions: Dimercaprol may increase the toxicity of cadmium, iron, selenium, or uranium salts.

How Supplied: Injection: 10%

Dosage
?Deep IM Only Mild arsenic and gold poisoning.
Adults: 2.5 mg/kg q.i.d. for 2 days; then, b.i.d. on the third day, and once daily thereafter for 10 days.
Severe arsenic or gold poisoning.
Adults: 3 mg/kg q 4 hr for days 1 and 2; q.i.d. on day 3; b.i.d. for 10 more days.
Mercury poisoning, mild.
Adults, initial: 5 mg/kg; then, 2.5 mg/kg 1 or 2 times/day for 10 days. Alternate dosing regimen: 2.5 mg/kg q 4 hr on day 1, q 6 hr on day 2, q 12 hr on day 3, and thereafter, once daily for the next 10 days or until recovery occurs.
Mercury poisoning, severe.
Adults: 5 mg/kg for the first dose followed by 2.5 mg/kg q 3 hr for the first 24 hr; then, 2 mg/kg q 4 hr on day 2; 3 mg/kg q 6 hr on day 3; and 3 mg/kg q 12 hr for the next 10 days or until recovery.
Mild lead encephalopathy.
Adults: 4 mg/kg alone initially; then, 3 mg/kg q 4 hr in combination with calcium EDTA administered in a separate site. Treatment should be continued for 2-7 days only if the blood level at the end of the first course of combined BAL-CaEDTA therapy exceeds 80-90 mcg/dL.
Severe lead encephalopathy.
Adults: 4 mg/kg alone initially; then, 4 mg/kg q 4 hr in combination with calcium EDTA administered in a separate site. Treatment should be continued for 2-7 days and repeated after an interval of 2 days for 5 additional days only if the blood lead level at the end of the first course of combined BAL-CaEDTA therapy exceeds 80-90 mcg/dL.
Lead toxicity in symptomatic children, acute encephalopathy.
75 mg/m ² q 4 hr (up to 450 mg/m ² in 24 hr). After the first dose, give calcium EDTA, 1,500 mg/m ² over a 24-hr period in divided doses q 4 hr at a separate IM site; maintain treatment for 5 days and after an interval of 2 days, the treatment may be repeated for 5 additional days.
Lead toxicity in children, other symptoms.
50 mg/m ² q 4 hr. After the first dose, give calcium EDTA, 1,000 mg/m ² over a 24-hr period in divided doses q 4 hr at a separate IM site; maintain treatment for 5 days and after an interval of 2 days, the treatment may be repeated for 5 more days if the lead levels are still high.