<unk> s have a narrow therapeutic index, i.e., the therapeutic dose is close to the toxic dose. Factors that increase the risk of toxicity include advancing age, cardiac status, and concomitant use of other drugs. However, serum drug levels are not useful for evaluating risk of arrhythmia or seizure in<unk>  overdose.
Tricyclic antidepressant overdose
Benzodiazepine overdose
Opioid overdose
Lithium toxicity
Nicotine withdrawal
Secondary poisoning
Benzodiazepine withdrawal syndrome
Carbamate poisoning