THE MANAGEMENT OF WITHDRAWAL SYNDROMES

In contrast to alcohol, the opiate withdrawal syndrome (appendix 3, page 117) is hardly ever life-threatening. Physicians should thus resist all requests for prescription of methadone without prior assessment by the local specialist substance misuse team. The only exceptions to this rule are in the pregnant opiate addict where there is a potential for withdrawal to precipitate spontaneous abortion or premature labour, and in the elderly addict with cardiovascular disease where there is a theoretical risk of increased sympathetic tone precipitating cardiovascular complications. In these circumstances a physical examination will usually suffice to exclude supervening complications, and if not referral to the appropriate obstetric or medical team for an opinion, rather than resorting to premature prescribing of methadone. If the client offers the name of a previous prescriber who can confirm the prescription, then medication may be continued with referral to the local specialist team.

In some cases it may be appropriate to commence detoxification without an interim period of methadone stabilisation; there is no contraindication to commencement of detoxification straight from heroin or any other opiate drug. However, there is evidence that the likelihood of completion of detoxification is greater if the patient has been first stabilised on methadone.

MEDICATION

The drug of first choice for opiate detoxification is lofexidine. Lofexidine is a central alpha-2 agonist which blocks the autonomic response to opiate withdrawal. It is a non-opiate, non-addictive and noncontrolled drug and as such holds some advantages over methadone as a detoxification agent. Its potential advantages over methadone in this context are the possibility for a more rapid completion of detoxification, and an earlier induction onto naltrexone if the latter is to form part of the after-care plan. Both the outcome of detoxification in terms of completion rates and the acceptability to the client in terms of subjective discomfort of detoxification are equivalent to methadone.

The major risk associated with administration of lofexidine is the development of postural hypotension and bradycardia. The client should be monitored on a twice-daily basis to ensure appropriate use of medication and prevent the occurrence of dose-related hypotensive reactions. Over-sedation due to lofexidine usage may also occur, and the patient should be warned to avoid the use of other CNS depressant drugs throughout the course of the detoxification.

Early concerns regarding lofexidine's potential to induce a marked hypotensive response are now thought to have been largely unfounded, and it increasingly the reputation of a safe drug. BNF guidelines regarding dosage regimes are probably excessively cautious terms of the low starting doses recommended, which may potentially lead to early relapse. The BNF regime should nevertheless be followed in the absence of documented specialist advice to the contrary:

• Initially 200 micrograms twice daily.
• Increased daily as necessary to control withdrawal, in steps of 200-400 micrograms daily to a maximum of 2.4mg daily.
• Withdraw gradually over 2 to 4 days (theoretical risk of rebound hypertension).
• Recommended duration of treatment 7 to 10 days.

Adjunctive medication to provide symptomatic relief may be prescribed as follows:

• Aches & pains:ibuprofen 400mg tds prn.
• Nausea & vomiting: metoclopramide 10mg tds prn.
• Diarrhoea: loperamide 2-4mg prn after loose stools - maximum 16mg in 24 hours.
• Insomnia: zopiclone 7.5 to 15mg nocte prn for a maximum of four weeks.

If the patient has been first stabilized on methadone, it may be appropriate to continue the methadone for the first two days of the lofexidine detoxification. Some authorities recommend this approach as a means of protecting the patient from excessive withdrawal during the early period of detoxification when the lofexidine dose is low. Equally, this approach may also be appropriate with detoxification straight from heroin.

Methadone for detoxification.

Detoxification using methadone is an appropriate alternative for some clients who do not wish to use lofexidine, or in whom lofexidine is contraindicated. Induction onto an initial stabilisation dose should be managed as described in Section C5, page 25. Following this, reduction to zero in daily increments of 5 to 10mg should take place over a period of up to two weeks depending on the starting dose.

Relapse is more likely towards the end of the schedule, when dosages reduce below 20mg daily, and it may be appropriate to reduce by smaller increments of 2 to 5mg for the final days of the detoxification. Adjunctive medication may be prescribed as described above for lofexidine detoxification. Methadone should never be prescribed in the absence of prior advice from the local specialist substance misuse service.

Subutex (buprenorphine) for detoxification.

Subutex is a valid alternative for opiate detoxification where the patient does not want detoxification with lofexidine. Care must be taken during induction onto Subutex as it may induce an opiate withdrawal syndrome in certain circumstances due to its partial agonist action. In general, Subutex may only be appropriate for opiate addicts with 'smaller' habits in the region of 1/4g heroin or less daily. If Subutex is chosen as the detoxification agent, induction onto an initial stabilisation dose should be managed as described in Section C5. A 7 to 10 day withdrawal regime can then be instituted by incremental reduction of dosage to zero. Adjunctive medication may be prescribed as described above for lofexidine detoxification.

Subutex should never be prescribed in the absence of prior advice from the local specialist substance misuse service.

Other pharmacotherapies for opiate detoxification.

The use of dihydrocodeine, codeine, carbamazepine, chlorpromazine and other drugs for opiate detoxification is not licensed and is not recommended.

MONITORING REQUIREMENTS IN OPIATE DETOXIFICATION

Each set of observations should include:

• Opiate withdrawal scale (appendix 9, page 129).
• Observation of level of consciousness.
• Pulse and blood pressure.

Observations should be performed:

• Immediately before the start of the detoxification.
• Twice daily for the first five days.
• As indicated thereafter.

Patients should usually be requested to cease opiate use by the night before detoxification is due to commence.

If the detoxification is occurring at home, then a nurse from the local specialist substance misuse team will act as the observer, and arrange with the GP for the dispensing of medication. In addition, home detoxification should only be commenced if there is a supportive spouse, family member or friend who is willing to remain with the client for a minimum of 72 hours, and for the majority of the rest of the week.

Example protocols for opiate detoxification may be found in appendix 10, page 130.

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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.