Physiological changes in pregnancy may be associated with changes in pharmacokinetics and toxicokinetics following overdose. Drug overdose should be treated as a medical emergency. Some drug overdoses should be treated using specific antidotes. Self-poisoning with aspirin can be treated by a dose of activated charcoal. Gastric decontamination with activated charcoal should be carried out when a patient presents within 1 hour of ingestion following digoxin poisoning. Calcium channel blockers are used in the treatment of hypertension, angina and arrhythmias. Hypotension should initially be treated with intravenous fluids. Beta-blockers are widely used antihypertensive and anti-angina agents, and poisoning resulting from this is treated with glucagon. Patients who ingest less than 30mg/kg body weight elemental iron require assessment and treatment. An abdominal X-ray should be performed following ingestion of a potentially toxic dose to determine the need for gut decontamination. Some drugs may be effectively removed by haemodialysis.