EMed

Cocaine overdose

Pharmacology

  • Absorbed across all mucosal surfaces
  • Hydrochloride form insufflated or injected IV
  • Ether extraction produces crack cocaine, which is heat stable and can be smoked
  • Nasal use = peak effect after 30 mins / duration of 1-3 hours - delayed and prolonged effect due to vasoconstriction
  • IV and inhaled routes = rapid peak effect (30 secs - 2 mins) with duration 15-30 mins

Pathophysiology

  • Sodium channel blockade resulting in:
    • Local anaesthesia
    • Quinidine-like effect with wide QRS & ↑QTc
    • Direct toxic myocardial effect with negative inotrope
  • CNS stimulation through activation of the sympathetic nervous system by blockade of presynaptic reuptake of Adrenaline, dopamine and serotonin (alpha stimulation)
  • Platelet aggregation enhanced

Clinical Features

Cardiac

  • Please see Cocaine Associated Chest Pain page
  • Coronary vasoconstriction/spasm = acute coronary syndrome [Bestbets]
  • Exacerbated by increased myocardial oxygen demand, smoking and enhanced platelet aggregation
  • Ventricular arrhythmias
  • Hypertension with risk of aortic dissection

CNS

  • ⇑⇑BP, focal cerebral vasospasm (enhanced by lactic acidosis, ↑ platelet aggregation and hyperpyrexia)
  • Cerebral infarction or haemorrhage
  • Euphoria and sense of alertness
  • Occasionally acute psychosis
  • Generalised complex epilepsy

Pulmonary

  • Pulmonary oedema - ? catecholamine mediated
  • Pneumonitis, asthma and bronchiolitis - due to immunological effects or due to adulterants in cocaine
  • Barotrauma with smoking crack cocaine due to valsalva manoeuvres thought to enhance the drug effect

Renal

  • Rhabdomyolysis-induced renal failure- exacerbated by vasoconstriction

Obstetric

  • Increased risk of spontaneous abortion, placental abruption
  • Intrauterine growth retardation - due to disruption of uteroplacental blood flow due to vasoconstriction and maternal hypertension

Diagnosis

  • ⇑HR, ⇑BP ± arrhythmias
  • ↑RR
  • ↑ T°
  • Altered mental state leading to coma ± seizures
  • Mydriasis
  • Diaphoresis
  • Consider occult trauma and associated drug use

Management

  • Sedation with benzodiazepines which ↓ central sympathetic outflow
  • Management of cocaine associated chest pain
  • Aggressive cooling for hyperthermia
  • Aggressive fluid resuscitation to maintain urine output
  • Treat seizures with benzodiazepines and further Rx as necessary
  • Urgent CT brain for all seizures as high incidence of primary intracranial pathology
  • Treat myocardial ischaemia with aspirin, nitrates and/or benzodiazepines [BestBets], heparin, opiates (see cocaine associated chest pain)
  • β-blockers contraindicated (unopposed alpha stimulation worsens coronary and peripheral vasoconstriction)
  • Exclude myocardial injury in all cases of chest pain (see cocaine associated chest pain)
  • Treat ventricular tachyarrhythmias and QTc prolongation with bicarbonate ± magnesium
  • Avoid anti-arrhythmics (including amiodarone)
  • Avoid epinephrine if cardiac arrest occurs
  • Treat ⇑⇑BP with nitroprusside. (Avoid labetalol as despite Α & Β blockade the predominant effect is beta-blockade.)
  • Prolonged neuromuscular blockade occurs with suxamethonium due to acquired pseudocholinesterase deficiency. Blockade rarely lasts more than 20 minutes
  • Body stuffers are people who swallow poorly packed cocaine to avoid arrest. Treatment is supportive as drug quantities are usually relatively small
  • Body packers are people who ingest large quantities of well packed cocaine in order to smuggle it. Severe toxicity and even death occur if even 1 pack ruptures
  • Asymptomatic - Conservative management [BestBets] with activated charcoal followed by whole bowel irrigation ("Klean-prep")with radiological imaging to ensure all packs are passed
  • Symptomatic - supportive treatment and laparotomy. Endoscopy can result in pack rupture

Content by Dr Phil Kaye, Dr Íomhar O' Sullivan. Last review Dr ÍOS 15/04/24.