Interactions Between ‘Street Drugs’ and

Prescribed Psychotropic Drugs Pharmacy Dept There is limited information available to guide safe and effective prescribing in this area. A summary is given below. Heroin/ Cocaine, Ecstasy, Cannabis Alcohol methadone Amphetamines

Cannabis use: •Both can cause sedation and •Cocaine can cause blood vessels to •Causes sedation constrict so reducing the blood •Increases the risk of developing in higher doses, reduce the Long term or binge drinking supply to the heart (heart attack) and schizophrenia respiratory rate (this decreases can: the oxygen supply to the brain (stroke). General •Can worsen existing psychotic •Damage your liver (will affect how brain). •Cocaine and amphetamine can symptoms such as voices and paranoia your body processes other Considerations •Methadone prolongs the raise blood pressure and cause medication). Cannabis can cause: cardiac QTc interval which can arrhythmias •Damage your brain (affect your •Weight gain, sedation and tachycardia lead to arrhythmias (abnormal •Ecstasy can cause dehydration & memory and ability to think (a fast heart beat). heart rhythm). hyperthermia (overheating). clearly).

First Generation •Antipsychotics can reduce the high from street drugs Antipsychotics •If you take ecstasy you may be more likely to develop movement disorders associated with first generation antipsychotics. (‘typicals’) •You may be more likely to experience tachycardia (fast heart beat), arrhythmias (abnormal heart rhythm), sedation and weight gain. Cannabis: •Increases risk of arrhythmias (heart Second Generation •Increases risk of sedation •Increases risk of sedation •Reduces the amount of olanzapine & rhythm disturbances). Antipsychotics •Risperidone may precipitate •Increases risk of low blood clozapine in your body •Risperidone may reduce the high methadone withdrawal pressure with olanzapine (‘atypicals’) •Can increase weight gain feeling experienced with cocaine •Increases risk of sedation with •Cannabis increases the risk of sedation some antidepressants •Increases risk of arrhythmias with •Increases risk of sedation with with some antidepressants. •Some SSRIs can increase the tricyclics. some antidepressants. Antidepressants •Some antidepressants can cause rapid amount of methadone in your •Increases risk of high blood •Increases toxicity in overdose with heart beat (especially tricyclics). body pressure with MAOIs. tricyclics. Cannabis can make this worse. •Increases risk of arrhythmias with tricyclic antidepressants. Anticholinergics •Can cause hallucinations, elation and impaired memory Lithium •Alcohol & ecstasy in particular can cause dehydration. Dehydration can precipitate lithium toxicity.

Valproate/ •Carbamazepine reduces the •All can affect the amount of methadone in your Carbamazepine body health of your liver

•Increases risk of sedation & •Increases risk of sedation & •Increases risk of over-sedation with •Increases risk of sedation respiratory depression reduction in respiratory rate Benzodiazepines high doses of cocaine •Accidental overdose possible •Benzodiazepine abuse possible