Substance abuse

Respiratory depression and pinprick pupils are two signs of opioid and opiate overdose. This is managed with naloxone, which competes for the binding opioid binding site, giving the body time to clear the drug from the system. Naloxone maybe given alongside dextrose (glucose), thiamine and flumezanil in a 'coma cocktail' to reverse or help manage some of the common causes of unconsciousness.

Yawning, sweating and vomiting are signs of opioid withdrawal. Other signs and symptoms include diarrhoea, cramps, myalgia and dilated pupils. Hallucinations are more likely to be associated with alcohol withdrawal (delirium tremons).

Methadone is a mu-receptor agonist that is used in the management of heroin addiction. Both methadone and buprenorphine are first line treatments for opioid detoxification (NICE CG52). Random testing, observation of medication, titrating the dose and psychosocial support are all recommended for improving compliance. Clopidogrel is used to prevent clots. While IV drug users have a higher risk of DVT, the use of anti-platelet agents is not included in the management of toxicity.

Patients are less likely to suffer side effects from buprenorphine because it is only a partial agonist. Buprenorphine and methadone are equally affective at treating opioid toxicity but methadone is cheaper, although the doses of methadone are larger.

Delirium tremons is a syndrome of confusion and agitation featuring hallucinations and paranoia following alcohol withdrawal. Wernicke's encephalopathy is a state seen in alcoholics involving confusion, ataxia and eye signs such as double vision, ophthalmoplegia, nystagmus and ptosis. This may precede Korsakoff's syndrome which is characterised by confabulation (making up memories) and antegrade and retrograde memory loss. Charles-Bonnet syndrome is the experience of life-like visual hallucinations in patients who have lost part of their sight.

Lorazepam is a short-acting benzodiazepine used in the treatment of delirium tremens. Alcohol binds to inhibitory GABA-A channels in the CNS. During alcohol withdrawal, there is a loss of alcohol and hence reduced inhibition of nervous signalling which then become over-excited. Lorazepam binds to GABA-A receptors to prevent this excitability and is slowly titrated down over a number of days. Source: https://bnf.nice.org.uk/treatment-summary/alcohol-dependence.html accessed 21 October 2020

Thiamine (vitamin B1) is used to prevent Wernicke-Korsakoff Syndrome, a debilitating and permanent side effect of alcohol misuse. Wernicke-Korsakoff Syndrome has the same symptoms as Wernicke's encephalopathy and Korsakoff syndrome, and can be used to refer to Korsakoff's syndrome when it follows Wernicke's encephalpathy. Thiamine may be given with other B vitamins and ascorbic acid, which alcoholic patients may be deficient in. Source: https://bnf.nice.org.uk/treatment-summary/alcohol-dependence.html, accessed 21 October 2020

Doctors should decide whether a patient's alcohol withdrawal should be managed as an inpatient or an outpatient. Patients with a high alcohol dependence or liver problems should be managed as an inpatient. IN both cases, a long-lasting benzodiazepine should be prescribed that is slowly titrated down over several days. Thiamine may be given to help prevent Wernicke's encephalopathy or Korsakoff's syndrome. Haloperidol would not be used in assisted alcohol withdrawal but could be used to treat delirium tremons in acute alcohol withdrawal (unlicensed). Naltrexone or acamprosate calcium can be given to alcoholics after withdrawal to stop them drinking again. Nalmefene is an alternative for use in severe alcoholics. Source: https://bnf.nice.org.uk/treatment-summary/alcohol-dependence.html accessed 21 October 2020 and Clark T, Day E and Fergusson E, Core Clinical Cases in Psychiatry, 2nd Ed, 2017, Taylor and Francis Group.

Cocaine inhibits dopamine reuptake so more dopamine remains in the synapse to excite the post-synaptic neuron.

Cannabis contains both CBD and THC. THC can induce psychosis and anxiety while CBD can be a sedative, antipsychotic and anxiolytic. Cannabis plants differ in the relative proportions of CBD:THC leading to different risks for psychosis.

MDMA is the active ingredient in ecstasy. Cocaine and heroin are both opioids. The active ingredient in speed is metamphetamine. Psilocybin is the active ingredient in magic mushrooms.