Objective—To compare efficacy and safety of meso-
2,3-dimercaptosuccinic acid (DMSA) and Ca EDTA for
treatment of experimentally induced lead toxicosis in
cockatiels ( Nymphicus hollandicus).
Animals—137 (69 females, 68 males) healthy cockatiels
between 6 months and 8 years old.
Procedure—Lead toxicosis was induced by placing
lead shot in the gastrointestinal tract. Treatment with
Ca EDTA (40 mg/kg of body weight, IM, q 12 h), DMSA
(40 or 80 mg/kg, PO, q 12 h), and sodium sulfate salts
(SSS; 0.5 mg/kg, PO, q 48 h) was initiated 4 days after
induction of lead toxicosis. Blood lead concentrations
were determined, using atomic absorption spectrophotometry.
Number of birds surviving and blood
lead concentrations were compared among groups.
Results—In Phase II of the study, administration of
DMSA and Ca EDTA significantly decreased blood
lead concentrations when used alone or in combination
in birds with lead toxicosis. Addition of SSS did
not result in further decreases in lead concentrations.
Eight of 12 (66.7%) birds without lead toxicosis given
80 mg of DMSA/kg did not survive to the end of the
study . Lesions related to treatment with chelating
agents were not detected during necropsy.
Conclusions and Clinical Relevance—DMSA and
Ca EDTA are effective chelating agents in cockatiels.
Because DMSA is administered orally, it may be easier
than other chelating agents for bird owners to
administer at home. However, the narrow margin of
safety of DMSA indicates that this agent should be
used with caution. (Am J Vet Res 2000;61:935–940)