OPIATES
Morphine and Codeine are two compounds found in opium. These two, as well heroin. dihydrocodeine, pethidine, and methadone are some of the drugs that are classified as narcotic analgesics. Codeine is sometimes used as a constituent in analgesic mixtures. Opiod group of drugs also include Buprenorphine, loperamide, Pentazocine and Diphenoxylate.
Heroin, a drug of abuse, is used by addicts in Sri Lanka who usually inhale it. Poisoning or abuse of these drugs causes many similar clinical features.
Symptoms and Signs
Poisoning can occur by ingestion, inhalation or injection. “Body packing” or carrying heroin in the gastrointestinal tract has also caused poisoning.
Pinpoint pupils, impaired consciousness and respiratory depression are the main features of poisoning.
There may be bradycardia, hypotension, hypothermia, and slow, shallow, respiration.
Convulsions and non- cardiogenic pulmonary oedema may be observed.
Withdrawal symptoms of narcotic analgesics in addicts include diarrhea, vomiting, lachrymation, sweating, yawning, fever, tremor, insomnia and dilated pupils.
Management
If the respiration is impaired, ensure a patent airway and give oxygen and assisted ventilation. In moderate to severe poisoning, management in an intensive care unit is recommended.
Give Naloxone 0.8 to 2 mg IV. Repeat at intervals of 3 minutes to a maximum of 10 mg, if there is no improvement in respiratory function. (paediatric dose: 10 micrograms/ kg. followed by 100 micrograms/kg if there is no response) As the effect of Naloxone lasts 30 to 60 minutes, repeated doses or intravenous infusions may be necessary at the rate of 0.4 to 0.8 mg/hour (For children 0.3 mg/ hour)
The effects of Naloxone should be visible within 1 to 2 minutes after administration. Failure to respond to a total dose of 10 mg usually indicates the following.
a) Poisoning is not due to opiates, or
b) Poisoning is due to a partial agonist or antagonist (to reverse the effect of these drugs much larger doses may be required, and it may prove impossible to reverse the effects of Buprenorphine), or
c) Hypoxic brain damage has occurred.
- Once the patient has regained consciousness, it is necessary to continue monitoring of respiratory and cardiovascular status.
- Induce emesis or consider gastric lavage when appropriate in conscious patients who have ingested a narcotic analgesic. In an unconscious patient, consider gastric lavage when appropriate after inserting a cuffed endotracheal tube.
- Give activated charcoal 50 to 100 g in 200ml water. Multiple dose activated charcoal may be useful
- Give adequate oral or IV fluids. Maintain a fluid balance chart.
If convulsions are presentoedema is usually transient and response to supportive therapy and naloxone.