Barbiturates are central nervous system depressant drugs, but unlike the opiate / opioid group, they are not effective against pain as-their action in the body does not involve the pain receptors in the brain. This group of drugs includes quinalbarbitone- (tuinal), pentobarbitone (nebutal), amylo-barbitone (amytal) etc. Barbiturate and barbiturate-type drugs eg methaqualone (mandrax), come in a variety of coloured tablets, capsules and dry ampoules so they can be taken by mouth or injected.

Barbiturates used to be prescribed for sleep problems and for anxiety and tension. With the increase in the prescription of benzodiazepines for these conditions, fewer barbiturates find their way onto the illicit market and are now quite rare.



Barbiturates taken in low doses generally make the user feel relaxed and sociable producing tranquillity without drowsiness. With higher doses, the depressant effect increases and the need to sleep grows. The user must want to stay awake to gain the experience he/she intends. This usually results in clumsy and staggering co-ordination, poor speech control, unpredictable mood swings and mental confusion.

This disorientation is particularly dangerous as a lethal dose of barbiturates can be as little as 10-12 pills, possibly less with alcohol, and a user in a state of confusion could easily exceed the dose. The disorientation can also give rise to accidental injury because of falling and other environmental hazards. These effects usually last around 3 - 6 hours depending upon the size of the dose, followed by deep sleep and an alcohol-type hangover the next day.

Barbiturates are best avoided by people suffering from liver or kidney disorders, respiratory or heart disease, diabetes or anaemia because of their depressant effects.



Tolerance develops to barbiturates, but while more has to be taken to achieve the same level of intoxication, the level needed to overdose and cause respiratory failure remains relatively stable. There is an increased risk of pneumonia with long term use as the cough reflex is suppressed and the lungs are insufficiently cleared. In the same way as alcohol and opiates, barbiturates dilate the peripheral blood vessels, such that hypothermia can set in far easier when intoxicated. This loss of heat can aggravate the tendency towards respiratory infection.



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