CNS
On this page 7 sections
PSYCHIATRIC PHARMACOLOGY
Opioids
| Drug | Key point |
|---|---|
| Morphine | Analgesia; respiratory depression, constipation |
| Fentanyl | Potent opioid; risk of profound respiratory depression |
| Methadone | Long-acting opioid; QT prolongation risk |
| Buprenorphine | Partial μ agonist; high receptor affinity |
| Naloxone | Opioid antagonist used in overdose |
Opioid toxicity
Classic features include:
- Reduced consciousness.
- Respiratory depression.
- Pinpoint pupils, although pupils may not always be pinpoint.
Antidote: Naloxone, with repeat dosing or infusion when needed because some opioids outlast naloxone.
Antidepressants
| Class | Examples | Important adverse effects |
|---|---|---|
| SSRIs | Sertraline, fluoxetine, escitalopram | GI effects, sexual dysfunction, hyponatremia, bleeding risk |
| SNRIs | Venlafaxine, duloxetine | GI effects, possible increased BP |
| TCAs | Amitriptyline, imipramine | Anticholinergic effects, orthostatic hypotension, cardiac toxicity in overdose |
| MAO inhibitors | Phenelzine, tranylcypromine | Hypertensive reactions with tyramine; many interactions |
| Atypical antidepressants | Bupropion, mirtazapine | Drug-specific effects |
Serotonin syndrome
May occur with combinations of serotonergic drugs.
Typical features:
- Agitation.
- Hyperreflexia and clonus.
- Autonomic instability.
- Hyperthermia in severe cases.
Antipsychotics
| Class | Examples | High-yield adverse effects |
|---|---|---|
| Typical | Haloperidol, chlorpromazine | Extrapyramidal symptoms; prolactin effects |
| Atypical | Risperidone, olanzapine, quetiapine | Metabolic effects vary; risperidone can increase prolactin |
| Clozapine | Treatment-resistant schizophrenia | Agranulocytosis, myocarditis, seizures and metabolic effects |
Extrapyramidal symptoms
| Reaction | Typical management concept |
|---|---|
| Acute dystonia | Anticholinergic treatment such as benztropine |
| Drug-induced parkinsonism | Dose adjustment or selected anticholinergic treatment |
| Akathisia | Dose review and selected adjunctive treatment |
| Tardive dyskinesia | Medication review; VMAT2 inhibitors in appropriate cases |