Dimercaprol (British anti-lewisite antigen) is a metal chelating agent that is used in the treatment of arsenic, mercury, gold, and lead poisoning.

Indications of Dimercaprol:

• It is an antidote for gold, arsenic (except arsine), or acute mercury poisoning (except non-alkyl mercury), an adjunct to edetate CALCIUM disodium in acute lead poisoning.

Note: The use of dimercaprol in the management of poisoning from other heavy metals has not been validated.

Dimercaprol dose in Adults

Note: Before using dimercaprol, it's suggested to take another medicine called a histamine H antagonist, like diphenhydramine. This helps to prevent allergic reactions or side effects that might happen during treatment. So, it's like taking a medicine to reduce the chance of feeling sick or having a bad reaction.

Dimercaprol dose in the treatment of acute mild Arsenic or gold poisoning:

In the treatment of mild arsenic or gold poisoning, the recommended dose of dimercaprol is typically administered deep into the muscle (intramuscular injection). The dosage regimen usually follows this schedule:

• 2.5 milligrams per kilogram of body weight (mg/kg) every 6 hours for 2 days.
• Then, every 12 hours for 1 day.
• Finally, once daily for the following 10 days.

This dosage regimen helps to effectively remove the toxic metals from the body over a period of time, gradually decreasing the frequency of administration as the treatment progresses. It's important to follow the prescribed schedule carefully to ensure proper treatment and minimize the risk of side effects.

 

Dimercaprol dose in the treatment of acute severe Arsenic or gold poisoning:

In cases of severe acute arsenic or gold poisoning, the recommended dosage of dimercaprol is typically administered deep into the muscle (intramuscular injection). The dosage regimen generally follows this schedule:

• 3 milligrams per kilogram of body weight (mg/kg) every 4 hours for 2 days.
• Subsequently, every 6 hours for 1 day.
• Finally, every 12 hours for the next 10 days.

This dosing regimen is designed to rapidly remove the toxic metals from the body during the acute phase of poisoning, gradually tapering the frequency of administration as the treatment progresses. It's crucial to adhere to the prescribed schedule precisely to ensure effective treatment and minimize the risk of adverse effects.

Dimercaprol dose in the treatment of acute inorganic mercury poisoning:

For acute mercury (inorganic) poisoning, the recommended dosage of dimercaprol typically involves deep intramuscular injection. The dosage regimen generally consists of:

• An initial dose of 5 milligrams per kilogram of body weight (mg/kg).
• Followed by maintenance doses of 2.5 mg/kg administered 1-2 times per day for a duration of 10 days.

This dosing regimen aims to swiftly initiate treatment by administering a higher initial dose, followed by lower maintenance doses to help eliminate the mercury from the body over the course of treatment. Adherence to the prescribed schedule is crucial for effective management of poisoning and minimizing potential adverse effects.

Dimercaprol dose in the treatment of Lead poisoning:

For the treatment of lead poisoning, particularly in cases where blood lead levels are very high or when symptoms of poisoning are present, dimercaprol is used in conjunction with edetate calcium disodium.

• When blood lead levels are ≥70 mcg/dL, symptomatic lead poisoning, or lead encephalopathy:
  • Administer 4 milligrams per kilogram of body weight (mg/kg) every 4 hours for a duration of 2-7 days.
  • Some experts recommend a treatment duration of at least 3 days.

It's important to initiate treatment with edetate calcium disodium alongside the second dose of dimercaprol. This combination therapy helps to effectively chelate and remove lead from the body. Adherence to the prescribed dosage and schedule is crucial for optimal management of lead poisoning, particularly in severe cases.

Dimercaprol dose in Childrens

Note: Before using dimercaprol, it's suggested to take another medicine called a histamine H antagonist, like diphenhydramine. This helps to prevent allergic reactions or side effects that might happen during treatment. So, it's like taking a medicine to reduce the chance of feeling sick or having a bad reaction.

Dimercaprol dose in the treatment of acute mild Arsenic or gold poisoning:

For infants, children, and adolescents with mild acute arsenic or gold poisoning, the recommended dose of dimercaprol is administered via intramuscular injection. The dosage regimen is typically as follows:

• 2.5 milligrams per kilogram of body weight (mg/kg) per dose.
• Administered every 6 hours for 2 days.
• Subsequently, every 12 hours on the third day.
• Then, once daily thereafter for a total duration of 10 days.

This dosing schedule is designed to effectively treat mild poisoning by gradually reducing the frequency of administration as treatment progresses. It's important to adhere strictly to the prescribed dosage and schedule to ensure optimal treatment outcomes and minimize the risk of adverse effects.

Dimercaprol dose in the treatment of acute severe Arsenic or gold poisoning:

For infants, children, and adolescents with severe acute arsenic or gold poisoning, the recommended dosage of dimercaprol involves intramuscular injection. The dosage regimen typically follows this schedule:

• 3 milligrams per kilogram of body weight (mg/kg) per dose.
• Administered every 4 hours for 2 days.
• Then, every 6 hours on the third day.
• Subsequently, every 12 hours thereafter for a total duration of 10 days.

This dosing regimen is intended to rapidly address the severity of poisoning by administering higher doses initially, followed by gradually reducing the frequency of administration as treatment progresses. Adherence to the prescribed dosage and schedule is essential for effective management of severe poisoning and to minimize the risk of adverse effects.

Dimercaprol dose in the treatment of acute Mercury poisoning:

For infants, children, and adolescents with acute mercury poisoning, the recommended dosage of dimercaprol typically involves intramuscular injection. The dosage regimen generally follows this schedule:

• An initial dose of 5 milligrams per kilogram of body weight (mg/kg).
• Followed by maintenance doses of 2.5 mg/kg per dose.
• Administered 1 to 2 times per day.
• This treatment regimen continues for a duration of 10 days.

This dosing schedule aims to swiftly initiate treatment with a higher initial dose, followed by lower maintenance doses to help eliminate the mercury from the body over the course of treatment. Adherence to the prescribed dosage and schedule is crucial for effective management of acute mercury poisoning and to minimize potential adverse effects.

Dimercaprol dose in the treatment of Lead poisoning as an adjunct with edetate calcium disodium:

For infants, children, and adolescents with lead poisoning, particularly those with blood lead levels ≥70 mcg/dL, symptomatic lead poisoning, or lead encephalopathy, dimercaprol is used adjunctively with edetate calcium disodium. The recommended dosage of dimercaprol, administered via intramuscular injection, is as follows:

• 4 milligrams per kilogram of body weight (mg/kg) per dose.
• Administered every 4 hours.
• The treatment duration can vary from 2 to 7 days, with some experts recommending a minimum therapy duration of at least 3 days.

It's important to initiate treatment with edetate calcium disodium alongside the second dose of dimercaprol. This combination therapy helps to effectively chelate and remove lead from the body. Adherence to the prescribed dosage and schedule is crucial for optimal management of lead poisoning, especially in severe cases.

Pregnancy Risk Factor C

• Dimercaprol has a Pregnancy Risk Factor C, which means there haven't been studies on pregnant animals, and there aren't enough studies on pregnant women to know its effects.
• Lead poisoning during pregnancy can harm the baby, leading to problems like premature birth, low birth weight, and issues with brain development.
• Even low levels of lead in the mother's blood can cause problems.
• Pregnant women with high blood lead levels, particularly over 70 mcg/dL, should consider chelation therapy, which helps remove lead from the body.
• However, it's crucial to consult experts and consider alternatives, as dimercaprol may not always be the best option during pregnancy.
• If a pregnant woman has lead poisoning with symptoms like encephalopathy, chelation therapy should be considered regardless of the pregnancy stage.

Dimercaprol use during breastfeeding:

• It's unclear whether dimercaprol is present in breast milk, but since it's not absorbed orally, the exposure to a breastfed baby would likely be limited.
• However, dimercaprol isn't typically recommended for treating lead poisoning in adults unless their blood lead levels are above 50 mcg/dL.
• For lactating patients with confirmed blood lead levels of 40 mcg/dL or higher, breastfeeding should be avoided, and breast milk should be pumped and discarded until lead levels drop below 40 mcg/dL.
• The World Health Organization (WHO) suggests avoiding using the milk from a lactating patient undergoing lead poisoning treatment to feed a child if possible, especially for infants younger than one month, premature babies, or those with G-6-PD deficiency.
• If breastfeeding is necessary, infants should be monitored for conditions like hemolysis and jaundice.

Dose adjustment in renal disease:

• The manufacturer's labeling for dimercaprol doesn't provide specific adjustments for renal insufficiency.
• However, if a patient develops acute renal insufficiency during treatment with dimercaprol, extreme caution should be exercised, and the therapy may need to be discontinued.
• Renal insufficiency can affect how the body processes medications, so careful monitoring and adjustment of dosage may be necessary in such cases.

Dose adjustment in liver disease:

• The use of dimercaprol is generally contraindicated in individuals with hepatic insufficiency, except in cases of postarsenical jaundice.
• Postarsenical jaundice is a specific condition caused by arsenic poisoning, where the liver is affected.
• In such cases, dimercaprol may still be used under close medical supervision, even though the liver function is compromised.
• However, in other cases of hepatic insufficiency where there is no specific indication for dimercaprol, its use should be avoided due to potential risks and lack of established efficacy.

Side effects of Dimercaprol:

• Cardiovascular:
  • Chest Pain
  • Hypertension (Dose-Related)
  • Tachycardia (Dose-Related)
• Central Nervous System:
  • Anxiety
  • Burning Sensation (Lips, Mouth, Throat)
  • Headache
  • Nervousness
  • Paresthesia (Hand)
• Dermatologic:
  • Diaphoresis
• Gastrointestinal:
  • Abdominal Pain
  • Nausea
  • Salivation
  • Sore Throat
  • Vomiting
• Genitourinary:
  • Burning Sensation Of The Penis
• Hematologic & Oncologic:
  • Leukopenia (Polymorphonuclear)
• Infection:
  • Abscess
• Local:
  • Pain At Injection Site
• Neuromuscular & Skeletal:
  • Weakness
• Ophthalmic:
  • Blepharospasm
  • Conjunctivitis
  • Lacrimation
• Renal:
  • Renal Insufficiency (Acute)
• Respiratory:
  • Pharyngeal Edema
  • Rhinorrhea
  • Throat Irritation
• Miscellaneous:
  • Fever

Contraindications to Dimercaprol:

• Dimercaprol is contraindicated in individuals with hepatic insufficiency, except in cases where the hepatic insufficiency is specifically caused by arsenic poisoning.
• This means that if the liver is not functioning properly due to reasons other than arsenic poisoning, the use of dimercaprol should be avoided due to potential risks associated with impaired liver function.

Warnings and precautions

Nephrotoxicity:

• Dimercaprol has the potential to be nephrotoxic, meaning it can harm the kidneys.
• Therefore, it should be used cautiously in patients with oliguria (reduced urine output).
• To safeguard the kidneys, it's important to maintain an alkaline urine pH, as this prevents the breakdown of the dimercaprol-metal complex.
• If renal insufficiency occurs during treatment, the medication should either be discontinued or used with extreme caution.
• In cases of renal dysfunction, hemodialysis may be considered to remove the dimercaprol-metal chelate from the body.

Dimercaprol: Drug Interaction

Note: Drug Interaction Categories:

• Risk Factor C: Monitor When Using Combination
• Risk Factor D: Consider Treatment Modification
• Risk Factor X: Avoid Concomitant Use

Risk Factor X (Avoid combination)
Iron Salts	Dimercaprol may enhance the nephrotoxic effect of Iron Salts.
Multivitamins/Minerals (with ADEK, Folate, Iron)	Dimercaprol may enhance the adverse/toxic effect of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, Dimercaprol may enhance the nephrotoxic effect of Iron Salts.

Monitoring parameters:

Renal Function:

• Dimercaprol can potentially harm the kidneys, so caution is needed in patients with reduced urine output (oliguria).
• It's important to monitor kidney function closely during treatment.

Urine pH:

• Maintaining an alkaline urine pH is crucial to protect the kidneys.
• This prevents the breakdown of the dimercaprol-metal complex.

Infusion-Related Reactions:

• Keep an eye out for any reactions that might happen during the infusion of dimercaprol.
• Notify healthcare providers if any unusual symptoms occur.

For Lead Poisoning:

• Monitor blood lead levels before starting treatment and again 7-21 days after completing chelation therapy.
• Regularly check hemoglobin or hematocrit levels, iron status, and free erythrocyte protoporphyrin or zinc protoporphyrin.
• Watch out for any changes in neurodevelopment.

For Arsenic Poisoning:

• Measure urine arsenic concentration to assess the effectiveness of treatment.
• Regular monitoring helps gauge the response to therapy and adjust treatment as needed.

How to administer Dimercaprol?

Administration Method:

• Administer all injections deeply into the muscle (intramuscular injection).
• Rotate injection sites to prevent discomfort and tissue damage.

Maintaining Urine pH:

• Ensure urine pH remains alkaline to safeguard kidney function.
• This prevents potential harm to the kidneys during treatment.

Treatment of Lead Poisoning:

• When treating lead poisoning, administer dimercaprol separately from edetate calcium disodium.
• Using different injection sites for each medication minimizes the risk of interaction or interference between the two treatments.

Mechanism of action of Dimercaprol:

• The sulfhydryl group in dimercaprol binds with ions of different heavy metals, forming stable and soluble compounds called chelates.
• These chelates are not harmful and can be easily excreted in urine.
• This process helps to remove the toxic heavy metals from the body, reducing their harmful effects.

Absorption:

• IM (Intramuscular): Dimercaprol is absorbed rapidly when injected into the muscle.
• Oral: Dimercaprol is not absorbed when taken by mouth.

Distribution:

• Dimercaprol is distributed throughout the body, including the brain. It reaches all tissues.

Metabolism:

• The liver metabolizes dimercaprol quickly into inactive substances.

Time to Peak, Serum:

• It reaches peak levels in the bloodstream within 0.5-1 hour after administration.

Excretion:

• Dimercaprol is eliminated from the body through urine and feces, primarily via the bile.

International Brands of Dimercaprol:

• Bal in Oil
• A.L.

Dimercaprol Brand Names in Pakistan:

No Brands Available in Pakistan.