What drug withdrawal states are relevant to ICU practice? Outline the principles of their management.
Drug withdrawal states in ICU patients may be more common than is generally appreciated. They include –
• Alcohol
• Tobacco (nicotine)
• Narcotic (heroin, morphine)
• Benzodiazepines
• Caffeine
• Other street drugs (cocaine etc)
Principles of their management include –
• prevention (avoid prolonged high dose narcotics, benzodiazepines
• detection/diagnosis (be alert for signs eg agitation, tachycardia, fever)
• sedation (may be necessary to control systemic effects)
• replacement/substitution (eg nicotine patch)
• support (airway and respiration, fluid replacement)
• simple measures such as but firm communication, reality orientation, visible clock and presence of a relative contribute to reassurance of the patient.
The following withdrawal syndromes seem relevant:
Receptor | Drugs | Clinical withdrawal syndrome | Management options |
GABAA | Alcohol Barbiturates Benzodiazepines Organic solvents |
CNS excitation (agitation, tremor, hallucinations, seizures) Autonomic stimulation (tachycardia, hypertension, hyperthermia, diaphoresis) |
Benzodiazepines Dexmedetomidine |
GABAB | GHB Baclofen |
Dyskinesia, seizures, hypertension, hallucinations, psychosis, and coma. | Benzodiazepines |
Opioid | Opiates | CNS excitation (agitation, tremor, hallucinations) Diarrhoea, mydriasis, nausea. Autonomic stimulation (tachycardia, hypertension, hyperthermia, diaphoresis) |
Clonidine Dexmedetomidine |
Adenosine | Caffeine | Head-ache (cerebral vasodilation), fatigue, and hypersomnia (motor inhibition) | - |
Nicotinic acetylcholine receptor |
Nicotine | Agitation, insomnia, poor concentration, poor gut motility, poor feed tolerance. | Varenicline? |
Noradrenenaline | Amphetamines | Agitation, dysphoria, somnolence | - |
Dopamine | Cocaine | Anhedonia, irritability, exhaustion | - |
Cannabis | Agitation, insomnia, poor gut motility | Mirtazapine ? |
The college presents an excellent summary of the generic principles of managing drug withdrawal:
In greater detail:
In this context, "prevention" is not some sort of grassroots social work movement to gets the kids off their street drugs, but rather the push towards intelligent use of opiates and benzodiazepines in the ICU. Rationalising the infusions should prevent the development of iatrogenic withdrawal syndromes. Fortunately, the ICU environment typically does not favour true psychological addiction, as the pleasurable context of drug use is not present.
In this context, detection describes vigilant monitoring for drug withdrawal:
The supportive management of drug withdrawal aims to reduce the harm from the physiological and psychological consequences of withdrawal:
The aim is to replace the drug of addiction with a less harmful substance which offers submaximal receptor stimulation, so that the symptoms of withdrawl are ameliorated and the harm of pursuing the addiction is reduced. Examples of this include methadone and varenicline.