| SSRIs, SNRIs and other new generation antidepressants | Tricyclic antidepressants | Antipsychotics | Lithium |
---|
| Severe poisoning caused by an SSRI or other new generation antidepressant alone is rare. | Poisoning is rare but exceptionally severe. | Tolerance may be low if the patient is unaccustomed to antipsychotics. | People who have not previously used lithium may tolerate even high doses, and people using lithium may show symptoms of poisoning at even only slight overdose |
Active ingredients belonging to the group | Fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, escitalopram Venlafaxine, mirtazapine, reboxetine | Nortriptyline, amitriptyline, clomipramine, trimipramine, doxepin | Chlorpromazine, levomepromazine, promazine, chlorprothixene, thioridazine, haloperidol, perphenazine Olanzapine, risperidone, quetiapine, clozapine | Lithium |
Mechanism of action | Inhibition of reuptake of serotonin (in some cases noradrenaline or dopamine) | Inhibition of reuptake of serotonin, noradrenaline and dopamine in nerve cells + sodium channel blockade | Dopamine receptor blockade, in some cases also effects such as serotonin, muscarine or histamine receptor blockade | Exact mechanism of action not known |
Clinical picture | - GI symptoms: nausea, vomiting
- CNS symptoms: vertigo, restlessness, ataxia, tremor, mild sedation, rarely deep unconsciousness or convulsions
- Hyponatraemia
- Venlafaxine may also cause anticholinergic symptoms or QT interval prolongation
- Serotonin syndrome possible
| - Anticholinergic symptoms (urinary retention, paralytic ileus, dry mouth, visual disturbances, mydriasis)
- Sedation, confusion, ataxia
- Treatment-resistant convulsions
- Respiratory depression, respiratory distress
- Haemodynamic failure
- Widened QRS complex, ventricular tachycardia
| - Anticholinergic symptoms
- CNS symptoms: agitation, confusion, extrapyramidal symptoms, impaired consciousness, convulsions
- Disturbed temperature regulation
- Hypotension, arrhythmia; QT interval prolongation; torsades de pointes with a delay of as long as 15 h for some agents
- In long-term use, neuroleptic malignant syndrome is possible
| - GI symptoms: nausea, vomiting, diarrhoea
- CNS symptoms: restlessness, confusion, tremor, ataxia, muscle weakness and stiffness, impaired consciousness, convulsions
- Respiratory depression
- Arrhythmia, hypotension
|
Treatment | - Wide QRS: consider sodium bicarbonate (Nabic*).
- Beware of agents prolonging the QT interval (such as ondansetron, amiodarone)!
| - Intubation anaesthesia at an early stage; medicinal charcoal
- Anticholinergic effects: medicinal charcoal may be useful for a longer time.
- Wide QRS, arrhythmia: Nabic*
- Recurrent VT: lidocaine
| - The anticholinergic effect slows down absorption; therefore medicinal charcoal may be useful for a longer time.
- Avoid agents prolonging the QT interval (such as ondansetron, amiodarone)!
- Torsades de pointes: magnesium
- Wide QRS: consider Nabic*
| - Not bound to medicinal charcoal.
- Elimination can be accelerated by dialysis.
- Treatment guided by lithium levels, which do not correlate directly with the severity of poisoning; symptoms are one of the factors determining the need for treatment and monitoring.
|