Drug withdrawal syndromes - Adverse Drug Reactions (ADR)

Drug withdrawal syndromes

·        Alcohol: tremor, sweats, tachycardia, ­BP, seizures, visual hallucinations, delirium

·        Opioids: anxiety, lacrimation, fever, runny nose, muscle aches, nausea, vomiting, diarrhoea, dilated pupils, tachycardia. Give naloxone for overdose (give test dose first, in case its not opiates). Pentazocine and Buprenorphine also used

·        BZD Withdrawal:

o   Anxiety, insomnia, depersonalisation, perceptual disorders, tremor, maybe seizures and confusion

o   Usually short acting (long acting less likely to give withdrawal affects)

o   Eg Triazolam: rebound wakefulness (can last 4 – 7 days). Also behavioural disinhibition, amnesia, confusion, etc

o   If severe then weight loss, autonomic dysfunction, ¯BP, ­¯ temp, tachycardia, psychosis, seizures. Have to restart drug and withdraw slowly

·        Propranolol withdrawal:

o   All b blockers can do it: but more common with short acting (eg propranolol and metoprolol). Less common with long acting (atenolol) or slow release

o   On withdrawal, sympathetic activity overshoots due to receptor up-regulation while on drug

o   Palpitations, sweating, apprehension, arrhythmias, etc. Peak is 3 – 5 days following withdrawal, especially with physical activity

·        Clonidine withdrawal:

o   Antihypertensive.  Pre-synaptic a2 agonists ® inhibits nor-adrenaline release

o   Withdrawal in 10% ® sudden rise in BP 24 – 72 hours later, plus other sympathetic effects

o   Similar effect in methyldopa (antihypertensive used in pregnancy)

·        Diuretics: eg frusemide, thiazides.  ­Na retention over 4 – 5 days.  Returns to normal

·        TCAs, phenothiazines, butyrophenones: headache, nausea, vomiting, confusion in elderly. Sleep disturbance