Understanding the Causes of Sudden Death: Heroin, Cocaine, and Benzodiazepines
Etiology of Sudden Death in Heroin Overdose
Heroin Overdose: A lethal dose of heroin is approximately 100-200mg intravenously, but oral administration requires twice this amount. Several factors contribute to sudden death:
- Variable Purity: The same dose of heroin can be lethal if the purity is higher than expected.
- Adulterants: The presence of poisonous adulterants, whether intentional or not, can contribute to death.
- Decreased Tolerance: After a period of abstinence, the user’s tolerance decreases. Administering the previous dose can be fatal. There is also a strong psychological component.
- Allergic Reactions: Anaphylactic reactions can occur. A user may become habituated to a specific composition of the drug. Cessation and subsequent use can result in allergic sensitization to certain components.
Toxicity of Cocaine
Acute Toxicity
- Low Dose: Euphoria, sexual arousal, increased physical capacity and mental well-being, hyperactivity, and increased sexual desire. Intravenous use may cause spontaneous ejaculation.
- Average Dose: Tachycardia, hypertension, hyperthermia, mydriasis (pupil dilation), tremors, sweating, hallucinations, and signs of “magma” (possibly referring to a state of intense stimulation).
- High Dose:
- Early Stimulation: Restlessness, irritability, hallucinations, headache, vomiting, tachycardia, hyperthermia, and hypertension.
- Advanced Stimulation: Seizures, severe hypertension, cardiovascular collapse, hyperactive reflexes, irregular breathing, and death.
- Depression: Muscle weakness, absent reflexes, somnolence, stupor, coma, cardiorespiratory arrest, and death.
Complications of psychiatric origin, such as manic episodes, can occur. When the euphoria subsides, depression, inability to concentrate, apathy, melancholy, and aggression are common. Overdose can lead to cerebral hemorrhage and peripheral arterial disease (PAD).
Chronic Toxicity
Digestive disorders, poor appetite, weight loss, and severe nervous and mental symptoms are common. These include: great excitability, mood swings, a paranoid psychotic state with hallucinations, and delusions of persecution. Ulceration and perforation of the nasal septum can occur due to sustained vasoconstriction.
Benzodiazepines
Benzodiazepines, introduced in the 1960s, were responsible for 40% of drug poisonings. They have a high level of safety but enhance the action of other psychodepressant drugs. Therapeutic use and poisoning are more common in women.
Toxicity
Benzodiazepines are absorbed orally, parenterally, and rectally. They undergo hydrolysis in the intestinal tract and blood, transforming into an active metabolite, nordiazepam. They are rapidly distributed throughout the body, crossing the placental and blood-brain barriers, and passing into breast milk. Metabolism occurs in the liver through dealkylation, hydroxylation, and glucuronide conjugation. Metabolites are excreted in the urine.
Classification
Benzodiazepines are classified according to their duration of action:
- Long-acting: Half-life (t1/2) > 24 hours (e.g., Diazepam).
- Intermediate-acting: Half-life (t1/2) 6 to 24 hours (e.g., Oxazepam).
- Short-acting: Half-life (t1/2) < 6 hours (e.g., Midazolam).
Clinical Manifestations of Acute Poisoning
Symptoms are similar to barbiturate poisoning but less pronounced. The therapeutic margin is very broad, and fatal poisonings are rare. When consumed in isolation, symptoms include drowsiness, apathy, ataxia, and dysarthria. It can lead to a deep coma, hypotension, and mild respiratory depression. Recovery typically occurs within 24 hours after poisoning, although metabolites may remain in the blood for days.