Symptoms: Overdosage of oral salbutamol produces symptoms that are mainly extensions of common adverse effects of salbutamol (e.g., seizures, hypotension or hypertension, arrhythmias, palpitation, nervousness, dizziness, fatigue, malaise, insomnia/sleeplessness, headache, tremor, dry mouth, nausea). In addition to exaggeration of common adverse effects, angina, tachycardia and hypokalemia have occurred following overdosage.
Overdosage of guaifenesin is unlikely to produce toxic effect since its toxicity is low.
Treatment: The drug should be discontinued and appropriate symptomatic therapy initiated. A relatively selective β1-adrenergic blocking agent (e.g., metoprolol tartrate) may be used, if necessary, but only with extreme caution in asthmatic patients because an asthmatic attack may be induced. Evidence is insufficient to determine if dialysis is beneficial for the management of overdosage with salbutamol.