Clinical Pharmacology and Therapeutics

436 DRUGS AND ALCOHOL ABUSE
Table 53.4: Symptoms of the opioid abstinence syndrome
Early Intermediate Late
Yawning Mydriasis Involuntary muscle spasm
Lacrimation Piloerection Fever
Rhinorrhoea Flushing Nausea and vomiting
Perspiration Tachycardia Abdominal cramps
Twitching Diarrhoea
Tremor
Restlessness
Withdrawal symptoms can be treated acutely by substitution
with a longer-acting opioid agonist (e.g. methadone by
mouth) or a partial agonist (e.g. buprenorphine, administered
sublingually). The dose can be tapered over one to two
weeks. Alternatively, withdrawal symptoms are alleviated by
lofexidine (an α 2 -antagonist with less marked hypotensive
effects than clonidine) and an antidiarrhoeal agent, such as
loperamide, administered over 48–72 hours.
MANAGEMENT OF OPIOID ADDICTS
Opioid addicts should be managed by specialized addiction
clinics when possible. A highly simplified outline of management
is summarized in the Key points below. Morbidity of
opioid dependence is related more to the use of infected needles,
injection of unsterile material, adulterants and cost (e.g.
theft, prostitution) than to the acute toxicity of opioids per se.
Key points
Management of opioid addicts in hospital
• Attempt to confirm addiction by telephoning
prescriber. Confirm dosing regimen.
• Obtain urine screen for a full drug misuse screen.
• Look for evidence of needle marks.
• Look for signs of opioid withdrawal.
• Contact psychiatric liaison team.
• In the Accident and Emergency Department, it is rarely
appropriate to prescribe methadone. If clear
withdrawal signs are evident, treat symptomatcially
(e.g. with antidiarrhoeal agent); discuss with psychiatric
liaison team regarding dose titration.
• For in-patients, methadone may be appropriate –
consult with psychiatric liaison regarding dose titration.
• Analgesia – address needs as for other patients, but
note the effects of tolerance.
• On discharge, contact the patient’s usual prescriber, or
if this is a new presentation make arrangements
through psychiatric team.
An orally available long-acting opioid antagonist, such as naltrexone,
is sometimes used as an adjunct to maintain abstinence
once opioid-free. (If given prematurely naltrexone precipitates
withdrawal.) Few opioid addicts choose to remain on longterm
antagonist therapy, in contrast to long-term methadone.
Opioid addicts rarely present to hospital asking for treatment
of their addiction, but more commonly present to physicians
during routine medical or surgical treatment for a
condition which may or may not be related to their addiction.
Some patients will deny drug abuse and clinical examination
should always include a search for signs of needle-tracking
and withdrawal. Acute abstinence in a casualty/general hospital
setting is uncomfortable for the patient, but most unlikely
to be dangerous. Physicians are not allowed to prescribe diamorphine
or cocaine to addicts for treatment of their addiction or
abstinence unless they hold a special licence. It is reasonable to
treat a genuine opioid withdrawal syndrome with a low dose
of opioid (e.g. sublingual buprenorphine). If a patient says
that they are being treated for addiction it is always wise to
confirm this by telephoning their usual prescriber and/or the
supplying pharmacist. If the patient is admitted to hospital,
expert advice must be obtained. Knowledge of local policies
towards drug addicts is essential for anyone working in the
Accident and Emergency Department or who comes into contact
with drug addicts. Newborn children of addicted mothers
may be born with an abstinence syndrome or, less commonly,
with features of drug overdose. Assisted ventilation is preferred
to naloxone if apnoeic at birth in this situation.
Key points
Management of opioid dependence
• Refer to specialized addiction clinic.
• Conduct assessment (to include two urine samples
positive for opioids).
• Give maintenance treatment (e.g. full agonists such as
methadone, or partial agonists such as buprenorphine).
• Give antagonist treatment (e.g. naltrexone).
• Provide detoxification regimens (e.g. lofexidine plus
loperamide).
• Give counselling/social support.
• Repeat urine testing to confirm use of methadone and
not other drugs.
• Contract system.
• Avoid prescriptions of other opioids/sedatives.
• Special ‘drug-free’ centres – concentrate on
psychological and social support through the acute and
chronic abstinence phases, and are successful in some
patients.
There are legal requirements for the prescription of controlled
drugs (Misuse of Drugs Regulations, 1985) distinguished in the
British National Formulary by the symbol CD (e.g. diamorphine,
morphine, injectable dihydrocodeine, dipipanone, fentanyl,
buprenorphine, dexamfetamine, methylphenidate, Ritalin ® ,
barbiturates, temazepam). Among the requirements are that the
prescription must be written by hand by the prescriber, in ink,
with the dose and quantity of dose units stated in both figures
and words (see British National Formulary). Diamorphine, dipipanone
and cocaine may only be prescribed to an addict for their
addiction by doctors with a special licence. Doctors are expected
to continue to report the treatment demands of all drug misusers
by returning the local drug misuse database reporting forms,