Common Medications Used in Psychiatry and Their Side Effects
Common Medications Used in Psychaitry and Their Side Effects
Selective serotonin re-uptake inhibitors (SSRI)
Selective serotonin re-uptake inhibitors (SSRIs) (e.g. fluoxetine)
Adverse effects in children and adolescents
- Agitation, behavioural disinhibition or 'activation', headache, skin rashes, GIT disturbances (decreased appetite, nausea, diarrhoea) and CNS effects, e.g. insomnia, tremor, and sedation.
- Increased risk of suicidality is associated with the use of SSRIs in depressed children and adolescents.
- A less common but potentially serious side effect is serotonin syndrome, which presents, in increasing severity, as restlessness, tremor, shivering, myoclonus, confusion, convulsions and death.
- Less commonly, SSRIs can induce bleeding and mania and may reduce the seizure threshold.
Special precautions/investigations/monitoring
- Adverse events may be dose related; reduce where indicated.
- Monitor for:
- suicidal ideation/agitation,
- ‘manic switch’ (SSRIs may precipitate mania), and
- serotonin syndrome symptoms (high dosages of SSRIs or the simultaneous use of two SSRIs in cross tapering).
Tricyclic antidepressants (e.g. amitriptyline)
Adverse effects in children and adolescents
- Sedation, anticholinergic side effects, cardiac side effects, convulsions, coma.
- May be more cardio-toxic in children than in adults.
Special precautions/investigations/monitoring
- Dangerous and potentially fatal in overdose. Avoid in children and adolescents with pre-existing cardiovascular disease.
- Do not use in conjunction with other drugs that prolong the QT interval.
- Baseline and on-treatment ECGs should be performed in patients with pre-existing cardiovascular conditions or a positive family history.
- May precipitate mania.
Stimulant medications (e.g. methylphenidate)
Adverse effects in children and adolescents
- Common: loss of, or decreased appetite, poor weight gain and insomnia.
- Common initially: headache, abdominal pain.
- Dysphoria or emotional blunting at high doses.
- May precipitate or worsen tics.
- May, at higher doses, lower the seizure threshold and precipitate seizures in children and adolescents suffering from epilepsy.
Special precautions/investigations/monitoring
- Monitor blood pressure, pulse rate, height and weight.
- Monitor for mood changes and the development of tics.
- Use with caution in children who suffer from epilepsy.
- Exclude absence seizures prior to initiating stimulants (clinical/EEG).
- Perform an ECG prior to initiating stimulants where a cardiac history or clinical cardiac pathology is present.
'Atypical' antipsychotics (e.g. risperidone, olanzapine)
Adverse effects in children and adolescents
- Common in children/adolescents: insomnia, agitation, anxiety, headache, sedation and extrapyramidal side effects (EPSE), e.g. acute dystonia, Parkinsonism, akathisia, tardive dyskinesia.
- Weight gain and metabolic syndrome.
- Sedation at higher dosages.
- Hyperprolactinaemia (gynaecomastia, galactorrhoea, menstrual disturbances) – particularly risperidone.
- Hyponatraemia due to polydipsia or SIADH – particularly risperidone.
Special precautions/investigations/monitoring
- Monitor weight.
- Monitor prolactin level, glucose and lipid profile in patients initiated on atypical antipsychotics.
'Typical' antipsychotics (e.g. haloperidol)
Adverse effects in children and adolescents
- EPSE: acute dystonia, akathisia, tardive dyskinesia, Parkinsonism.
- Life threatening side effect: Neuroleptic malignant syndrome (NMS): fever, altered mental status, muscle rigidity, autonomic dysfunction, raised creatinine kinase and white cell count. In case of suspected NMS, stop all antipsychotics.
Special precautions/investigations/monitoring
- Monitor for EPSE.
- Avoid long-term use where possible due to the risk of irreversible tardive dyskinesia.
Benzodiazepines (e.g. lorazepam, diazepam, clonazepam)
Adverse effects in children and adolescents
- Sedation, restlessness and paradoxical reaction of disinhibition, especially in children and adolescents with intellectual disability, neurological illnesses or brain trauma.
Special precautions/investigations/monitoring
- Not for long-term use.
Mood stabilisers (e.g. lithium carbonate, sodium valproate/valproic acid)
Lithium carbonate:
Adverse effects in children and adolescents
- Drug interactions – preferably avoid (or monitor closely): NSAIDS, ACE inhibitors, angiotensin receptor blockers, antithyroid agents, thiazide and loop diuretics, xanthines and SSRIs.
- Dose-related effects: ataxia, lethargy, thirst, GIT intolerance.
- Toxicity: confusion, vomiting, tremor, convulsions, coma.
- Non-dose-dependent: GIT, tremor, weight gain, goitre (hypothyroidism), hypoparathyroidism, nephrogenic diabetes insipidus, EPSE, polyuria.
Special precautions/investigations/monitoring
- Blood investigations: FBC, urea, creatinine and electrolytes, CMP, TSH and BHCG.
- Cardiac investigation: ECG.
- Ongoing monitoring: lithium levels 1 - 3 monthly, TSH and creatinine 6 - 12 monthly.
Valproic acid/Sodium valproate:
Adverse effects in children and adolescents
- Common: GIT (nausea, vomiting, constipation, diarrhoea).
- Dose-related effects: fatigue, sedation, ataxia.
- Uncommon: hair loss, skin rashes, increased appetite, tremor, amenorrhoea, aggression, depression.
- Rare: hepatotoxicity (potentially lethal), pancreatitis, hyperammonaemia.
- Pregnancy: facial anomalies, neural tube abnormalities.
Special precautions/investigations/monitoring
- Check liver functions and ammonia levels prior to initiation and then 6 monthly.
- Blood levels must be done in the morning prior to the morning dosage if there are concerns about compliance and toxicity. No routine indication.
- Monitor for signs of hepatotoxicity
Caution
The choice of agent for girls and women of childbearing potential must be carefully considered. Valproate should be avoided in adolescent women and preadolescent girls who are likely to remain on treatment into their childbearing years unless other treatment is ineffective or effective contraception is in place. This is due to the risk of adverse developmental outcomes to the foetus.
If the decision is made to use valproate in patients in this population, complete the ‘Acknowledgement of Risk’ form: https://www.sahpra.org.za/wp-content/uploads/2020/08/6.28_Valproate_Annual_Risk_Acknowledgement_Form_Dec18_v1.pdf
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Paediatrics, 2023 Edition
Chapter 14: Child & Adolescent Psychiatry, Common Medications Used In Psychiatry And Their Side Effects