THE MANAGEMENT OF WITHDRAWAL SYNDROMES

A clinically significant sedative-hypnotic withdrawal syndrome is likely to occur following the discontinuation of a daily therapeutic dose (e.g. 20mg temazepam or equivalent [see appendix 7, page 123 for benzodiazepine equivalency doses]) after at least four months of treatment, or after as little as two months if doses more than twice the therapeutic dose have been used/ prescribed. The time course and severity of the withdrawal syndrome will be dependent on the dose prescribed, the duration it was prescribed for, the duration of action and potency of the particular drug and individual factors. The withdrawal syndrome is characterised by a host of symptoms and signs classically associated with anxiety, depression, and neuromuscular hyperactivity, and may in severe cases progress to seizures, psychosis and/or delirium (see appendix 3, page 117). Acute, severe withdrawal will usually resolve spontaneously within one month; however, as for the opiate and stimulant classes, a protracted withdrawal syndrome that is much less intense may persist for many months.

Individual factors predicting a more severe withdrawal syndrome and poor prognosis for successful discontinuation include psychiatric comorbidity (actively present in more than 50% of long-term benzodiazepine users), polydrug misuse, concurrent alcohol misuse, family history of alcoholism, older age and female sex. Polydrug misusing, concurrent alcohol misusing and comorbid patients should be referred for a specialist assessment before commencing discontinuation.

Assessment preceding detoxification must take into account the potential of the patient to experience re-emergent psychiatric symptoms or to precipitate an episode of psychotic illness in a patient with a past history of psychosis. Equally, in patients with medical conditions that are significantly influenced by adrenergic and psychological stress factors (e.g. cardiac arrythmias, asthma, SLE, inflammatory bowel disease), care must be taken to avoid precipitating complications.

The simplest means of withdrawal on an outpatient basis is to commence a tapering reduction regime. The rate of discontinuation for long-term users should be at a maximum of 5mg diazepam equivalents per week or 6% of the starting dose, whichever is smallest (see appendix 7, page 123 for equivalency doses). The final 20% of the taper should be slowed down considerably. If symptoms of withdrawal occur, the dose should be increased until the symptoms resolve and the taper then re-started at a slower rate.

Patients who are unable to tolerate such a regime may possibly respond to a substitution and tapering regime. Chlordiazepoxide (long duration of action and low abuse potential) should be used to replace the equivalent amount of other benzodiazepine (or barbiturate). Dosing should be on a four times daily regime to provide the most stable plasma levels possible. Allow one to two weeks to attain a steady state plasma concentration before commencing the taper. Commence the taper as above.

Patients who are unable to complete a community reduction or who require in-patient treatment for other reasons (e.g. comorbidity) should be referred to specialist services for access to in-patient detoxification. This is often best carried out using phenobarbital substitution which provides the smoothest and most effective withdrawal; completion of prescribing is also more rapid making this a more practical solution for use on an in-patient basis. Phenobarbital 30 to 60mg hourly PRN is titrated against withdrawal symptoms until a stable 24 hour dosage has been achieved; this process may take up to one week to achieve. The stabilisation dose is then administered in divided doses over the next 24 hours before commencing reduction at the rate of 30 to 60mg phenobarbital daily. The final 20% of the taper should be accomplished more slowly, possibly at a rate of reduction of 15 to 30mg every two days, depending on the patient's response.

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The above information is copyright of Dr Bruce Trathen MBBS MRCPsych (2006). ISBN 0-9545164-0-0. The author grants permission for these guidelines to be downloaded, copied and distributed freely, but does not grant permission for their sale.