| Paracetamol Liver damage is possible in adults who have taken 10g or more of paracetamol. Ingestion of 5g or more of paracetamol may lead to liver damage if the patient has risk factors (see below). Risk Factors If the patient:• Is on long term treatment with carbamazepine, phenobarbitone, phenytoin, primidone, rifampicin, St John's Wort or other drugs that induce liver enzymes.• Regularly consumes ethanol in excess of recommended amounts. Is likely to be glutathione deplete, e.g. eating disorders, cystic fibrosis, HIV infection, starvation, cachexia.Symptoms Symptoms of paracetamol overdosage in the first 24 hours include pallor, nausea, vomiting, anorexia and abdominal pain. Liver damage may become apparent 12 to 48 hours after ingestion. Abnormalities of glucose metabolism and metabolic acidosis may occur. In severe poisoning, hepatic failure may progress to encephalopathy, haemorrhage, hypoglycaemia, cerebral oedema and death. Acute renal failure with acute tubular necrosis, strongly suggested by loin pain, haematuria and proteinuria, may develop even in the absence of severe liver damage. Cardiac arrhythmias and pancreatitis have been reported. Management Immediate treatment is essential in the management of paracetamol overdose. Despite a lack of significant early symptoms, patients should be referred to hospital urgently for immediate medical attention. Symptoms may be limited to nausea or vomiting and may not reflect the severity of overdose or the risk of organ damage. Management should be in accordance with established treatment guidelines, see BNF overdose section. Treatment with activated charcoal should be considered if the overdose has been taken within 1 hour. Plasma paracetamol concentration should be measured at 4 hours or later after ingestion (earlier concentrations are unreliable) but results should not delay initiation of treatment beyond 8 hours after ingestion, as the effectiveness of the antidote declines sharply after this time. If required the patient should be given intravenous N-acetylcysteine, in line with the established dosage schedule. If vomiting is not a problem, oral methionine may be a suitable alternative for remote areas, outside hospital.Codeine Symptoms Central nervous system depression may develop as well as respiratory depression. The pupils may be pin-point in size and nausea and vomiting are common. Possible but unlikely effects are hypotension and tachycardia. The effects in overdosage of codeine are potentiated by simultaneous ingestion of alcohol and psychotropic drugs. Management If coma or respiratory depression is present give naloxone, preferably intravenously, at a dose of 0.4 to 2mg for adults and 0.01mg/kg body weight for children. Repeat the dose if there is no response within two minutes. Large doses (4mg) of naloxone may be required in a seriously poisoned patient. Intramuscular naloxone is an alternative in the event that IV access is not possible, or if the patient is threatening to self-discharge when it may help reduce the risk of respiratory arrest. Failure of a definite opioid overdose to respond to large doses of naloxone suggests that another CNS depressant drug or brain damage is present. Observe the patient carefully for recurrence of CNS and respiratory depression. Repeated doses of naloxone may be required. If so, intravenous infusion of naloxone may be useful. An infusion of 60% of the initial dose per hour is a useful starting point. A 200 microgram/ml solution for infusion using an IV pump can be used and the dose adjusted to clinical response. Infusions are not a substitute for frequent review of the patient's clinical state. A clear airway, adequate ventilation and oxygenation should be established without delay if consciousness is impaired. Consider activated charcoal (50g for adults; 10-15g for children) if an adult presents within 1 hour of ingestion of more than 350mg, or a child more than 5mg/kg, provided the airway can be protected. Observe patient for at least 4 hours after ingestion. Other supportive measures should be taken as indicated by the patient's progress.Caffeine Symptoms CNS stimulation: Anxiety, nervousness, restlessness, insomnia, excitement, muscle twitching, confusion. Cardiac: Tachycardia, cardiac arrythmia. Gastric: Abdominal or stomach pains. Other: Diuresis, facial flushing. The symptoms of caffeine overdose may be masked by the depression of consciousness associated with possible codeine overdose when associated with this combination. Treatment Treatment is primarily symptomatic and supportive. Acute toxicity is unlikely to occur with the low levels of caffeine in this product. CNS symptoms can be treated with intravenous diazepam, phenobarbitone or phenytoin. For cardiac symptoms monitoring of ECG is required. Diuresis should be treated by maintaining fluid and electrolyte balance. Gastric symptoms can be treated using antacids. If acute poisoning is suspected treatment generally includes emesis with ipecacuanha syrup and/or gastric lavage if caffeine has been ingested within 4 hours in amounts over 15mg/kg bodyweight. However whilst treatment of this nature would be beneficial in reducing absorption of caffeine, consideration would need to be given to the level on consciousness of the patient in view of the sedating effect of codeine in this product combination. Administration of activated charcoal may be useful within the first 4 hours if precautions are taken to minimize aspiration. Magnesium sulphate cathartic may also be helpful. To enhance elimination haemoperfusion is usually more effective than dialysis. | |
