Substance Abuse
A cocaine addiction causes changes in the Mesolimbic pathway, more specifically the Nucleus Accumbens.
Amphetamines present similarly to Hypomania i.e. elevated mood, over-talkativeness, increased energy, insomnia, HTN and pupil dilation. Its withdrawal presents with depression, fatigue, suicidal thoughts, and cravings. Managed with benzodiazepines, antipsychotics and anti-depressants. Crystal meth is a very addictive amphetamine that reaches high concentrations in the brain when smoked.
MDMA (Ecstasy) is a synthetic amphetamine analogue with mild stimulatory and hallucinogenic effects - “Safer” than cocaine or amphetamines.
Examples - Heroin, Fentanyl, Morphine, Codeine
Effect - Euphoria, analgesia, drowsiness, resp depression, bradycardia, pupil constriction, constipation.
Signs of OD - Pinpoint Pupils, Respiratory depression, Bradycardia, Hypotension
Reversed with Naloxone - Given until good, spontaneous ventilation
Patients are at a high risk of withdrawal following detox as they want to avoid the withdrawal effects. Withdrawal occurs 8-12hrs after last dose, lasting~10 days, and patients go ‘Cold Turkey’ – Pupil Dilation, Craving, Restlessness, Myalgia, Sweating, Abdo Pain, Tachycardia, Rhinorrhoea, Goosebumps
Resolves spontaneously, but can be medically supported with a substitute drug e.g. Methadone, Buprenorphine
N.B. Opioid toxicity is parasympathetic so everything goes down e.g. small pupils, respiratory depression, constipation, brady etc. Withdrawal is sympathetic, so has the opposite effects.
Neuroleptic Malignant Syndrome (NMS)
Caused by dopaminergic antagonists (e.g. haloperidol), and is characterised by ‘lead-pipe’ rigidity and hyporeflexia days to weeks after the drug is taken/started. Other signs include autonomic instability (often hypertension and tachycardia), tremor, clonus, agitation.
Serotonin syndrome (SS)
Caused by serotonergic agents (e.g. SSRI's, such as citalopram), and is characterised by hyperreflexia and clonus hours after the drug is taken/started. Other signs include autonomic instability (e.g. diarrhoea, hypertension, tachycardia), agitation, confusion, hypotonia, tremor.
