Severity Mild (150 mg/kg) Moderate (150–300 mg/kg) Severe (300–500 mg/kg) Toxicity No toxicity expected Mild to moderate toxicity expected Life-threatening toxicity expected Symptoms Nausea, vomiting, dizziness Nausea, vomiting, ringing in the ears, headache, confusion, hyperventilation, tachycardia, fever Delirium, hallucinations, seizures, coma, respiratory arrest