The New Straits Times, March 3, 1997
Q: I have come across reports about the use of cough preparations and sleeping drugs to sedate preschool children. What are these compounds and what are their effects when large doses are taken?
A: Drugs that can cause sedation act mainly on the brain and interfere with the complex mechanism of maintaining consciousness.
Although they can induce sleep, these drugs actually cause disruptions to the normal pattern of sleep such that the user normally has to rely on these drugs to be able to sleep.
A number of scientific reports has shown that many users get caught in a cycle of taking more medication to induce sleep, which in turn causes further disruption of sleep.
When the medication is discontinued after chronic use, the body would normally respond with a compensatory rebound of the steep pattern which is accompanied by additional sleep disturbances and nightmares.
Hence, the user would normally rely on further resuming taking the drug and the cycle would continue until professional intervention is sought.
Drugs that can cause disruptions in sleep patterns can be divided into two main groups, namely drugs, which prevent sleep and may cause nervousness, and drugs which induce sleep.
The latter group, to name a few, include drugs such as alcohol, amphetamines, barbiturates, anti-histamines, ethclorvynol, narcotics, benzodiazepines, choral hydrate, nicotine, phenytoin and tricyclic antidepressants.
In the above case, the drugs which may have been used are the antihistamine and codeine-containing cough preparations while the benzodiazepines and the barbiturates may have been used as the sleeping drugs.
The antihistamines are drugs which exert their effect in the body by blocking the action of histamine which is released primarily in allergic reactions such as in colds.
Besides blocking the allergic reaction, certain antihistamines are also used to reduce coughing in chronic cough patients.
The effects associated with the use of antihistamines are sedation and an identified syndrome known as anticholinergic reaction which is characterised by warm, dry, flushed skin; dry mouth; pupil dilation; urinary retention; hyperactivity; increased heart rate; jerky muscle movement; an increase in the body temperature and coma.
The codeine-containing cough preparations are now under stringent control in Malaysia as a result of their misuse by drug addicts.
There is no danger of physical or physiological dependence when codeine is used in recommended amounts for short periods. However, dependence may develop after prolonged use.
The effects most commonly encountered with codeine include nausea, drowsiness, light-headedness and constipation especially when recommended dosage levels are exceeded.
The barbiturates which are also under stringent control in Malaysia, are used as hynoptic and sedative agents depending on the administered dose, for the induction of anaesthesia and for the treatment of epilepsy and status epilepticus.
They are often divided into four major groups by their activity and clinical use; ultrashort-acting, short acting, intermediate-acting and long acting with the shorter acting ones having more toxic effect at a lower dose.
The effects normally encountered when taken at a large dose are lethargy, slurred speech, uncoordinated movement, a drop in the blood pressure, coma and respiratory arrest.
The drug class of benzodiazepines contain many compounds that vary widely in potency, duration of effect and clinical use in general, the toxic-therapeutic ratio for benzodiazapnes is very high.
However when taken in a large dose, the effects are associated with the depression of the central nervous system which include lethargy, slurred speech, jerky muscular movement, coma and respiratory arrest.
