10.6 Prescribing, treatment modalities and legal restrictions

Aims of treatment

• Goals are agreed with the person and include survival, fewer overdoses and infections, stable treatment, better functioning, and abstinence where they choose it.

• Stable maintenance without illicit use counts as recovery, and continued use should lead to a review of dose, mental illness and housing rather than exclusion.

• Opioid agonist treatment is linked in cohort studies with lower all-cause and overdose mortality, better retention and less injecting, and abrupt loss of care can raise mortality.

• Tolerance falls after detoxification, stopping treatment or leaving custody, so the first weeks carry a high risk of overdose if use resumes.

Opioid agonists: methadone and buprenorphine

Opioid agonists (methadone, buprenorphine) are the drugs for maintenance or substitution treatment and have the strongest evidence for long-term maintenance. Antagonists, alpha-2 agonists and short-acting opioids are not used for maintenance.

• Precipitated withdrawal occurs with buprenorphine because it binds more tightly than heroin but activates the receptor less; methadone, a full agonist, cannot precipitate withdrawal at induction.

• Buprenorphine maintenance keeps patients in treatment better than placebo or no medication.

• NICE (National Institute for Health and Care Excellence) names oral methadone as the drug to prescribe first for maintenance when methadone and buprenorphine are equally suitable.

• Levacetylmethadol (LAAM), a long-acting agonist, was withdrawn from maintenance after a European suspension in 2001 because it prolonged the QT interval and caused torsades de pointes.

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Buprenorphine preparations

• Subutex is buprenorphine alone.

• Suboxone is buprenorphine with naloxone, which is poorly absorbed sublingually but active if injected, where it can precipitate withdrawal and so deters injecting misuse.

Pregnancy

• Opioid dependence in pregnancy is managed by stabilising the patient on an opioid agonist, methadone having the longest evidence base, not by antagonists or rapid withdrawal.

• Any planned reduction in pregnancy needs specialist assessment of withdrawal, relapse and obstetric risks.

Detoxification

• Buprenorphine suits detoxification because it suppresses withdrawal while tapered and blunts heroin used on top, and it suits a patient who wants to avoid the sedation of a full agonist.

• Three drug groups have substantial evidence for relieving withdrawal: tapered methadone, buprenorphine and alpha-2 agonists (lofexidine, clonidine).

• Ultra-rapid detoxification uses high-dose antagonists such as naltrexone under general anaesthesia or heavy sedation to precipitate withdrawal, and NICE advises against it.

• Planned withdrawal needs informed choice, support, a relapse plan and take-home naloxone.

Alpha-2 agonists

• Lofexidine is a centrally acting alpha-2 adrenergic agonist that relieves opioid withdrawal by damping the noradrenergic rebound.

• Lofexidine is the non-opioid drug licensed in the UK for opioid withdrawal, for patients who decline methadone or buprenorphine; clonidine works the same way but is used off-label.

• Lofexidine lowers blood pressure and heart rate by reducing central sympathetic outflow, so it should be avoided in a patient who is already hypotensive.

• Clonidine commonly causes dry mouth and eyes, sedation, fatigue, dizziness, nausea, hypotension, bradycardia and constipation.

Opioid antagonists

• Naloxone is a short-acting competitive mu antagonist that reverses overdose of any opioid, but it lasts only about an hour, so a patient who took methadone can become drowsy again and needs observation and repeated doses.

• Naltrexone is the oral antagonist for relapse prevention in a motivated, supported patient who has completed detoxification and been abstinent for 7 to 10 days; it is not for people seeking maintenance.

• Longer opioid-free intervals may be needed after long-acting opioids, because naltrexone given before opioids have cleared displaces them from mu receptors and precipitates withdrawal, so people must be warned before the first dose.

• The evidence that naltrexone prevents relapse is inconclusive, although NICE judges it cost-effective for selected detoxified, motivated and supported patients.

• Naltrexone blocks opioid analgesia, overriding the blockade with large opioid doses is dangerous, and overdose risk rises after missed doses because tolerance is lower.

Alcohol relapse prevention

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Smoking cessation

The medicines licensed in the UK are nicotine replacement therapy, varenicline and bupropion.

• Weight gain after stopping averages about 5 kg at ten years and is greatest in heavier smokers, women, people with a higher pre-quit body mass index, lower socioeconomic status, and comfort eaters.

Other treatment modalities

• Harm reduction (sterile injecting equipment, infection testing and vaccination, overdose education, naloxone) complements treatment and reaches people not seeking abstinence.

• Residential rehabilitation gives intensive structure away from triggers but is costly, disruptive and variable in quality, and discharge needs plans for housing, medication and overdose.

• Mutual aid such as Narcotics Anonymous offers free peer support, though its spiritual framing does not suit everyone.

• Supervised consumption and instalment dispensing reduce induction and diversion risk, and they loosen as the patient stabilises after individual assessment.

Controlled drug law

Class does not determine schedule: cocaine is Class A and Schedule 2, while ordinary cannabis is Class B and Schedule 1.

• Controlled drug prescriptions state the dose, form, strength and total quantity in words and figures.

• Synthetic cannabinoids are Class B, so possession carries up to 5 years' custody, and pregabalin is Class C.

• A special licence is needed to prescribe diamorphine, dipipanone or cocaine for addiction, but not methadone or buprenorphine, even when methadone is injected.

• Home Office notification has ended in Great Britain, whereas Northern Ireland keeps seven-day doctor notification.

Consent, confidentiality and driving

• Dependence, intoxication or withdrawal does not automatically remove capacity, which is assessed for the particular decision.

• Having children is not a blanket exception to confidentiality, and safeguarding disclosures need a proper basis and proportionate information.

• People with persistent misuse or dependence must stop driving and notify the Driver and Vehicle Licensing Agency, or the Driver and Vehicle Agency in Northern Ireland.

Stable maintenance means no non-prescribed psychoactive use, good adherence and no other disqualifying condition.