Mild to Moderate Symptoms: Somnolence, anticholinergic syndrome (hyperexia, mydriasis, flushing, fever, tachycardia, dry mouth, urinary retention, decreased bowel sounds, agitation confusion and hallucinations), mild hypertension, nausea and vomiting are common after overdose. Cerebral stimulation in children and occasionally in adults, insomnia, nervousness, tremors, epileptiform convulsions may occur.Severe Symptoms: Effects may include delirium, psychosis, seizures, coma, hypotension, QRS widening, and ventricular dysrhythmias (including torsades de pointe), but are generally only reported in adults after large ingestions. Rhabdomyolysis and renal failure may rarely develop in patients with prolonged agitation, coma, or seizures. Death may occur as a result of respiratory failure or circulatory collapse.
Excessive use of menthol may lead to abdominal pain, vomiting, flushed face, dizziness, weakness, tachycardia, stupor, and ataxia.
Treatment of overdose should be symptomatic and supportive. Measures to promote rapid gastric emptying (with syrup of ipecac-induced emesis or gastric lavage) and, in cases of acute poisoning, the use of activated charcoal, may be useful.