Accidental ingestion of methadone by children in Merseyside

Patients, methods, and results

We obtained information on the circumstances, timing, dose, family history, clinical details, and outcome for all children who had accidentally ingested methadone syrup in the Mersey region during November 1989 to March 1993. There were 44 episodes in 42 children; the number increased from nine in 1990, 13 in 1991, to 18 in 1992. The average age of the children was 34 (range 11-84) months; 29 were boys.

In 30 cases the type of methadone container was known: 22 were screwtop bottles, three were cups, two were open lemonade bottles, one was cotton wool in a bottle top, and only two were child resistant containers.

In 32 cases the methadone had been prescribed for a parent. In the remainder it was prescribed for the parent's partner or relative. The estimated volume ingested ranged from a lick to 200 ml.

Most ingestions were during the day; only two occurred between midnight and 9 am. The average delay between ingestion and arrival at hospital was 1 hour 35 minutes (range 15 minutes to 12 hours).

Two children died, both before arrival at hospital and after considerable delay. Of the survivors, 21 were drowsy, 10 had respiratory depression, 17 had pinpoint pupils, four were hypotensive and two had convulsions. Seventeen were asymtomatic.

Twenty children were given a bolus of naloxone, 14 of whom also had a naxolone infusion. Twentytwo received ipecacuanha. Six needed no treatment. Thirty nine children were admitted, two were sent home, and one was taken home against medical advice. Twenty nine were in hospital for 24 hours, one for 24 - 48 hours, and six for three or more days (three for social reasons and three for chest infections). All three with chest infections had depressed levels of consciousness and respiration.

Comment

The number of accidental methadone ingestions by children doubled from 1990 to 1992. The Liverpool Drug Dependency Unit was established in 1989 with about 400 adults receiving methadone. In 1993 there were 800 patients, who were responsible for 500 children between them. Over half of Liverpool's family doctors prescribe methadone. In November 1992, 2739 prescriptions were issue for a total of 14831 of methadone syrup in Liverpool (family health services authority, personal communication).

Methadone is a long acting opiate (half life 25 hours) and is readily absorbed orally. It is given as a sweet green liquid containing the equivalent of 1 mg of morphine per ml. There is no legal requirement that it be dispensed in child resistant containers. Liverpool family health servicesauthority has funded the supply of such containers, and we recommend that this be done nationally.At present methadone is attractive in colour and taste; changing to a bitter tasting liquid would stop children taking large amounts.

Three reasons may account for the delay in seeking help. Firstly, methadone users may not realise the danger of the drug to children. Secondly, they may not know that there is an antidote, and,thirdly, parents may fear professional accusations of poor parenting. Methadone users must be made aware of its dangers. Liverpool Drug Dependency Unit has designed posters with suitable warnings and advice.

All children suspected to have ingested methadone should be admitted to hospital. An emetic should be given only if the child is alert. Children with symptoms should receive a bolus of intravenous naloxone followed by an infusion at a rate determined by clinical criteria. Respiratory support may be needed. If a child has taken large volumes the stomach should be emptied by lavage while the airway is protected.

Emetic should not be given before the child reaches hospital because of the risk of aspiration. Intramuscular naloxone can be given safely by paramedics or general practitioners: 400 mug for a child under 5 years and 800 mug for an older child.