Tranquillizers:
These are antianxiety drugs and as the name suggests peace the mind and relieve from worries. These bring relaxation, feeling of well being and may be some loss of inhibition but do not induce sleep or sedation. Tranquillizers are synthetic drugs. These are phenothiazines and benzodiazipines.

(a) Phenothiazines: These are antipsychotic drugs. In a psychotic patient, these drugs decrease aggressiveness and lower anxiety. Phenothiazine is the precursor compound for synthesis of  antipsyphotic drugs such as chloropromazine, thioridazine and reserpine etc. Reserpine is obtained from the roots of plant Rauwolfia species.

(b) Benzodiazipines: These are antianxiety drugs. These are mor popular barbiturates because these are more effective and almost no side effects and mild withdrawl symptoms. Benzodiazipines are precursor compounds for synthesis of many antiarixiety drugs like diazepam, oxazepam, chlonazepam, alprozolam and lerzepam.

The benzodiazepines are the worlds most highly used drugs. They produce their calming effect indirectly by increasing the action of Y - amino butyric acid. These drugs are available in the form of tablets, capsule and injections. But these should be taken in small doses and should be given when needed.
Withdrawal Symptoms: Withdrawal from tranquillizers can be as dangerous and painful as withdrawal from barbiturates. Combining the tranquillizing drugs with other, including alcohol is a highly dangerous form of abuse. Each drug, reinforce the effect of other drugs. Sudden pause after prolonged use results in insomnia, anxiety, irritability, restlessness, delirium, decreased appetite, sweating and trembling.
Rehabilitation: Gradual reduction of drug over a period of about 2 months under the supervision of physician.