Massive ingestion of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA)

To report the course of a massive ingestion of the herbicide 2-methyl-4-chlorophenoxyacetic acid or MCPA (4-chloro-2-methyl phenoxy acetic acid) and to correlate plasma 2-methyl-4-chlorophenoxyacetic acid levels with symptoms of intoxication and treatment.

After intentional ingestion of the herbicide, 2-methyl-4-chlorophenoxyacetic acid, a young man suffered burning in his mouth, spasmodic pain in the extremities and a severe hypotensive crisis. Plasma 2-methyl-4-chlorophenoxyacetic acid concentration was 546 mg/L two hours after ingestion. Therapy by forced diuresis was ineffective until the urine was alkalinized (Day 4). This resulted in a rapid decline of the plasma 2-methyl-4-chlorophenoxyacetic acid level to 6 mg/L and recovery of the patient.