Succimer
meso-2,3-dimercaptosuccinic acid (DMSA)
Also known as: Chemet · Succicaptal · meso-2,3 dimercaptosuccinic acid · DMSA · DIM-SA
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Lead poisoning | 10 mg/kg PO q8h | PO | q8h | 10 days | 🌎 NA |
| Lead poisoning | 10 mg/kg PO three times daily for 5 days, followed by 10 mg/kg PO twice daily for 2 weeks | PO | TID then BID | 19 days | 🌎 NA |
- Lead poisoning: Blood lead levels should be rechecked a few days following the last dose; a second round may be necessary.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Lead poisoning | 10 mg/kg PO three times daily for 5 days, followed by 10 mg/kg PO twice daily for 2 weeks | PO | TID then BID | 19 days | 🌎 NA |
| Lead poisoning | 10 mg/kg PO q8h | PO | q8h | 10 days | 🌎 NA |
- Lead poisoning: Blood lead levels should be rechecked a few days following the last dose; a second round may be necessary.
Birds
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Lead poisoning | 15-35 mg/kg PO twice daily | PO | BID | 5 days | 🌎 NA |
| Lead poisoning | 30 mg/kg PO twice daily | PO | BID | minimum of 7 days | 🌎 NA |
- Lead poisoning: If severe neurologic signs, may supplement with one dose of CaEDTA (<50 mg/kg IM).
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Succimer (DMSA) is an oral heavy metal chelating agent primarily utilized in veterinary medicine for the treatment of lead poisoning in small animals and birds. It is a water-soluble analog of dimercaprol (BAL) but offers the distinct advantage of oral administration and a significantly wider therapeutic index.
- Target Toxins: Highly effective for lead (Pb); potentially beneficial for arsenic (As) and mercury (Hg) toxicosis.
- Safety Profile: Generally safe and effective. It spares most essential trace elements (like zinc, copper, and iron) from being chelated and does not enhance lead absorption from the gastrointestinal tract.
Clinical Pearl: Succimer is often preferred over CaEDTA for lead poisoning in small animals because it can be given orally at home, is less nephrotoxic, and does not deplete essential minerals as aggressively.
Mechanism of action
Succimer acts as a heavy metal chelator through its sulfhydryl (-SH) groups.
- Binding: The sulfhydryl groups physically bind (chelate) heavy metal ions (such as lead, mercury, and arsenic) in the bloodstream and tissues.
- Complex Formation: Heavy metal + Succimer → Water-soluble chelate complex.
- Excretion: These stable, water-soluble complexes are subsequently filtered by the kidneys and excreted safely in the urine, thereby reducing the heavy metal burden in the body.
Safety & warnings
Contraindications
- Hypersensitivity to succimer
- Continued exposure to the lead source (source must be removed prior to or concurrently with therapy)
Adverse effects
- Gastrointestinal upset (vomiting, diarrhea)
- Flu-like symptoms (fatigue, body aches)
- Increased liver enzymes (AST, ALT)
- Rash
- Unpleasant sulfurous odor imparted to breath, saliva, urine, and feces
Precautions
Important Precautions
- Source Removal: Chelation therapy should only be attempted if the source of lead (e.g., lead paint, sinkers, shot) is removed from the GI tract and environment to prevent further absorption.
- Laboratory Interferences:
- Can cause false-positive urine ketones when using nitroprusside reagents (e.g., Ketostix).
- Can cause falsely low measurements of CPK or serum uric acid.
- Pregnancy & Nursing: FDA Category C. Fetotoxic and teratogenic at high doses in mice. Safety in pregnant or nursing animals is unknown; use with extreme caution and discourage nursing.
Drug interactions
Concomitant use is not recommended in humans due to potential for increased toxicity or altered efficacy.
Monitoring
- Blood lead levels (recheck a few days after completing therapy)
- Gastrointestinal adverse effects
- Liver enzymes (AST, ALT)
- Hydration status
Pharmacokinetics
Absorption
Rapidly but incompletely absorbed after oral ingestion (based on human data).
Distribution
No specific veterinary information available.
Metabolism
No specific veterinary information available.
Elimination
Absorbed drug is excreted primarily through the kidneys into the urine.
Overdose
Overdose & Toxicity
- Dogs: Succimer has a relatively wide margin of safety. Doses up to 200 mg/kg/day did not cause overt toxicity. However, massive doses (300 mg/day) caused fatalities, primarily presenting with kidney and GI tract lesions.
- Birds: Cockatiels are particularly sensitive to high doses. Doses of 80 mg/kg PO q12h caused a significant number of fatalities, whereas 40 mg/kg q12h did not.
- Treatment: If an acute overdose occurs, standardized gut evacuation (emesis/lavage) followed by activated charcoal protocols are recommended.
Available products
Formulations
- Capsules
Human-labeled
- Succimer Capsules: 100 mg (Chemet)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store succimer capsules in tight containers at room temperature. Protect from light.
Client information
Important Information for Pet Owners
- Strong Odor: This medication contains sulfur and has a very strong, unpleasant "rotten egg" odor. This is completely normal and does not mean the drug is bad.
- Odor Transfer: The smell may transfer to your pet's breath, saliva, urine, and feces during treatment.
- Administration: To make it easier to give, you can open the capsules and sprinkle the contents onto a small amount of highly palatable, soft food.
- Hydration is Key: Ensure your pet has constant access to fresh water. The drug binds to the lead and flushes it out through the urine, so good hydration is essential for the treatment to work safely.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.