Opiate withdrawal has fewer risks to alcohol withdrawal due to the absence of seizures and delirium tremens. It is often likened to a bad flu, but not by those who have been through it who would argue that it is a deeply unpleasant experience.
The onset of withdrawal symptoms will vary with the opiate that is being misused on the basis of its half-life, so for heroin (diamorphine) expect symptoms within 12 hours, whilst methadone has a longer half-life so symptoms may not appear until 30 hours after last use.
Early symptoms of withdrawal include:
• Agitation
• Anxiety
• Muscle aches
• Increased tearing
• Insomnia
• Runny nose
• Sweating
• Yawning
Late symptoms of withdrawal include:
• Abdominal cramping
• Diarrhea
• Dilated pupils
• Goose bumps
• Nausea
• Vomiting
Opiate abuse is life-threatening in overdose due to respiratory depression and in this case naloxone, an opiate antagonist can be used. Be aware that the half-life of naloxone is shorter than that of heroin so the patient will need multiple doses. Also be aware that using it will put them into withdrawal, so they will probably not want to stay in hospital and are not likely to thank you for your actions. This is a common and tricky situation in A&Es in areas with high use of heroin.
The management of opiate withdrawal and appropriate management
The mainstay of opiate detoxification is substitute prescribing with different opiates, largely managed by specialist substance misuse services, though some GPs do now operate shared care or manage a number of cases themselves.
Goals of treatment
- Detoxification – to treat the physical dependence – or
- Harm reduction, in this the aim is to provide substitute medication to reduce the need for illicit opiates and the related risks to the patient’s physical and psychological health whilst additionally reducing the negative social outcomes of dependent use such as crime in order to fund the addiction. As such a patient could potentially remain on a stable dose of substitute medication for years before they are ready to consider detoxification.
The substitute medications used in opiate dependence are:
- Methadone
- Synthetic opioid with a long half-life usually taken in liquid form
- Buprenorphine (subutex)
- Partial agoinist at opiate receptors – thus at higher doses has a blocking effect if opiates used at the same time making it protective to a certain degree
- Suboxone (buprenorphine plus naloxone)
- Acts in the same way as subutex but if tablet is crushed and injected then the naloxone becomes active and will reverse the action of the buprenorphine hence useful if there are concerns about misuse or diversion
As a junior doctor on the wards:
Check with the substance misuse service on prescribed dose for the patient, do not rely on patient report.
Why?
There is a risk of overdose in two ways:
- Patient knowingly deceives you in the hope of receiving a higher dose
- Patient informs you of the correct dose but has not been attending clinic or picking up prescription for three days or more
- Levels of opioid drop rapidly from steady state and the patient quickly loses tolerance to opioid hence dose that previously kept them comfortable now causes overdose
- Risks greater with methadone than buprenorphine
- Levels of opioid drop rapidly from steady state and the patient quickly loses tolerance to opioid hence dose that previously kept them comfortable now causes overdose
What can I do whilst waiting for information from substance misuse e.g. when patient admitted out of hours?
Treat symptomatically, in response to observed withdrawal:
- Benzodiazepines for agitation e.g. diazepam 10mg prn
- Metaclopramide 10mg for nausea
- Loperamide 4mg prn for diarrhoea
- Paracetamol and ibuprofen for muscle aches
- Lofexidine 400mcg bd – monitor for hypotension
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