Drug overdose Flashcards
What are the features of beta-blocker overdose?
Bradycardia, hypotension, heart failure, syncope.
What is the management for bradycardia in beta-blocker overdose?
If bradycardic, then atropine. In resistant cases, glucagon may be used.
Is haemodialysis effective in beta-blocker overdose?
Haemodialysis is not effective in beta-blocker overdose.
What drugs can be cleared with haemodialysis? (Mnemonic: BLAST)
Barbiturate, Lithium, Alcohol (including methanol, ethylene glycol), Salicylates, Theophyllines.
What drugs cannot be cleared with haemodialysis?
Tricyclics, benzodiazepines, dextropropoxyphene (Co-proxamol), digoxin, beta-blockers.
What are the major complications of iron overdose?
Metabolic acidosis, erosion of gastric mucosa → GI bleeding, shock, hepatotoxicity, and coagulopathy.
What is the management for patients who ingested > 40mg/kg elemental iron?
Need medical assessment with serum iron levels measured 2-4 hours post-ingestion and abdominal x-ray.
What is the decontamination procedure of choice for iron overdose?
Whole bowel irrigation is performed on all patients presenting within 4 hours who have ingested > 60mg/kg elemental iron or have undissolved tablets on abdominal x-ray.
When is desferrioxamine indicated in iron overdose?
In patients with serum iron level > 90umol/l, or 60-90umol/l who are symptomatic or have persistent iron on abdominal x-ray despite whole bowel irrigation, or any patient with shock, coma, or metabolic acidosis.
What are the features of lithium toxicity?
Coarse tremor, hyperreflexia, acute confusion, polyuria, seizure, coma.
What is the management for mild-moderate lithium toxicity?
Volume resuscitation with normal saline, IV fluids with isotonic saline until euvolemic, then typically twice maintenance rate.
What are the indications for acetylcysteine in paracetamol overdose?
Plasma paracetamol concentration on or above treatment line, staggered overdose, patients presenting 8-24 hours after ingestion of > 150 mg/kg, or > 24 hours if jaundiced or hepatic tenderness.
What is the King’s College Hospital criteria for liver transplantation in paracetamol liver failure?
Arterial pH < 7.3, 24 hours after ingestion, or all of the following: prothrombin time > 100 seconds, creatinine > 300 µmol/l, grade III or IV encephalopathy.
What metabolic pathway is affected in paracetamol overdose?
The liver normally conjugates paracetamol with glucuronic acid/sulphate; during overdose, the conjugation system becomes saturated, leading to the production of a toxic metabolite.
What groups of patients are at increased risk of hepatotoxicity from paracetamol overdose?
Patients taking liver enzyme-inducing drugs, malnourished patients, or those who have not eaten for a few days.
What are the features of salicylate overdose?
Hyperventilation, tinnitus, lethargy, sweating, pyrexia, nausea/vomiting, hyperglycaemia, hypoglycaemia, seizures, coma.
What is the treatment for salicylate overdose?
General (ABC, charcoal), urinary alkalinization with intravenous sodium bicarbonate, haemodialysis.
What are the causes of serotonin syndrome?
Monoamine oxidase inhibitors, SSRIs, St John’s Wort, tramadol, ecstasy, amphetamines.
What are the features of serotonin syndrome?
Neuromuscular excitation, hyperreflexia, myoclonus, rigidity, autonomic nervous system excitation, hyperthermia, sweating, altered mental state, confusion.
Venn diagram showing contrasting serotonin syndrome with neuroleptic malignant syndrome. Note that both conditions can cause a raised creatine kinase (CK) but it tends to be more associated with NMS.
What is the management for tricyclic overdose?
IV bicarbonate for hypotension or arrhythmias, correction of acidosis, intravenous lipid emulsion to bind free drug.
