1. A careful history should be taken, and a thorough examination made. If the patient is registered, then the drug centre, the GP or the psychiatrist should be contacted to verify details. Expert advice on management may be necessary. If doubt exists, urine may be tested for the presence of drugs. Belongings should be checked for concealed drugs.
2. Patients should be presumed to be HBV and HIV positive unless proved otherwise.
3. Most authorities are agreed that the perioperative period is not the correct time to institute detoxification. Opiates will therefore need to be given.This may be the preparation already being used, or the equivalent dose of methadone might be substituted. Approximately equivalent dosages (DHSS 1984) are reported as:
a) Methadone: 10 mg (some authorities quote 5 mg).
d) Dextromoramide: 5 mg.
f) Dipipanone: 20 mg.
g) Buprenorphine: 0.8 mg.
h) Pentazocine: 125 mg.
If genuine organic pain does exist then, as a result of tolerance, higher than normal doses of opiates will be required.There is also a variability in cross tolerance to opioids, such that when patients still have uncontrolled pain in spite of intolerable side effects, an alternative drug may be substituted with success (Collett 1998).
5. Partial opiate antagonists such as pentazocine, or pure antagonists such as naloxone, should not be used since they may produce severe acute withdrawal symptoms.
6. The use of other drugs with addictive potential, such as the benzodiazepines, should be avoided.
7. Hypotension has been described preoperatively in opiate addicts.When it occurs during surgery, responses to various forms of treatment including opiates, fluids, vasoconstrictors or hydrocortisone have been reported.
8. Opioids should continue to be given in labour, calculated as a minimum daily requirement (Birnbach 1998).There is little evidence that opiates are harmful to a fetus already exposed to opiates during pregnancy and respiratory depression is thought not to be a feature.There is no contraindication to epidural analgesia.
Birnbach DJ 1998 Anesthesia and the drug abusing parturient.Anesthesiology Clinics of North
America 16:385-95. Caldwell T 1990 Anesthesia for patients with behavioral and environmental disorders. In: Katz J, BenumofJ,
Kadis L, (eds).Anesthesia and uncommon diseases.
WB Saunders, Philadelphia,pp 794-812.
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