How Do Certain Drugs Put Us to Sleep?
Some drugs, called hypnotics, put us to sleep by producing a depressive or slowing-down effect on our central nervous system. They act upon an area of the brain that controls the wake-sleep cycle. The drugs differ greatly in the medicinal dosage required, the duration of their action and the margin of safety between a helpful dose and a dangerous one.
Long-acting barbiturates, such as phenobarbitone or Luminal, are effective for six to ten hours and prolonged use may make the user drowsy next day. Intermediate acting drugs, like butobarbitone or Soneryl, and amylobarbitone or Amytal, last for about five to six hours.
Short-acting ones like pentobarbitone or Nembutal last from two to three hours and ultra-short acting drugs like thiopentone or Pentothal are used mainly as forerunners to anaesthetics. Barbiturates can have injurious effects and should be taken only under strict medical supervision.
Hypnotics may be prescribed by a physician, but their long-term efficacy is poor and they have numerous adverse effects including daytime drowsiness, accidents, memory disorders and withdrawal symptoms.
If they are to be taken, the preferred choices are benzodiazepines with short-lasting effects such as temazepam or the newer Z-medicines such as zopiclone. Alternatively, in isolated cases sedatives such as barbiturates may be prescribed.