BENZOTHIADIAZINE

Toxicology

Bentazon is a drug in this class.

Bentazon is a polar, acidic herbicid.

Oral doses ofbentazone were rapidly and almost completely absorbed in rats. The compound was quite rapidly excreted  mostly unchanged in the urine (approximately 91% within 24 hours), with only traces secreted into bile (0–2.9%) (JMPR,2012).

A study in rats showed that the rate and extent of absorption were similar after administration of the sodium salt and free acid forms of bentazone (JMPR,2012).

Bentazon causes allergy-like symptoms as it irritates the eyes, skin and respiratory tract (Toxnet)

Clinical Manifestation

Ingestion of large amounts of bentazon cause fevers (hyperthermia), muscle rigidity, rhabdamyolysis and kidney failure, tachycardia, shortness of breath (dyspnea) prolongation of prothrombin time and metabolic acidosis (Toxnet;Emre et al 2011).

Human poisoning mimicking neuroleptic malignant syndrome has been reported

Ingestion of 88 grams of bentazon caused death in an adult

Clinical Management

There is no antidote for bentazon poisoning.

Treatment is symptomatic and supportive.

Fluid and electrolyte replacement may be necessary.

Because of acidic nature of bentazon, emesis is NOT recommended

For recent ingestion (less than 1 Hr post take), administer charcoal as a slurry 1 kg/kg bwt upto 100g in an adult (240mL water/30 g charcoal).

Treat hyperthermia by keeping skin damp and using cooling fans.

Muscle rigidity can be managed with benzodiazepines.

Rhabdamyolysis is managed with intravenous 0.9% saline (10 to15 mL/kg/hour) to maintain urine output of at least 1 to2 mL/kg/hour (or greater than 150 to 300 mL/hr). Closely monitor input and output, serum electrolytes, CK, and renal function. Diuretics may be considered if urine output is inadequate after volume status is restored (Toxnet).

If cough or difficulty breathing develops, administer oxygen and assist ventilation as required. Treat bronchospasm with an inhaled beta2-adrenergic agonist eg salbutamol. Systemic corticosteroids should be considered in severe bronchospasm (Toxnet).

For prolonged PT , consider Vitamin K replacement (Emre, 2011).

References

Toxnet, Toxicology Data Network. Bentazon. https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+3430. Last Revision Date: 2018/12/18

JMPR ,Joint FAO/WHO Meeting on Pesticide Residues (2012). BENTAZONE 31–98 . apps.who.int/pesticide-residues-jmpr-database/Document/52

Emre H, Keles M, Uyanik A, Mucahit Emet Mc, Bilen Y, Bayraktutan D (2011). Case Report 59. Rhabdomyolysis and acute renal failure as a result of bentazone intoxication. Eastern Journal of Medicine 16 59-61

 

 

 

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