Common medications used in psychiatry and their side effects

Selective serotonin re-uptake inhibitors (SSRI) 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 associated with the use of SSRIs in depressed children and adolescents.
  • 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 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’ (SSRI may precipitate mania)
    • serotonin syndrome symptoms (high dosages of SSRI or the simultaneous use of two SSRI’s in cross tapering)

Tricyclic Antidepressants (e.g. amitriptyline)

Adverse effects in children and adolescents

  • Sedation, anticholinergic, 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 condition or 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).
  • ECG prior to initiating stimulants where 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.

Special precautions/ investigations/monitoring

  • Monitor for EPSEs.
  • Avoid long term use where possible due to 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 close monitoring): 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: 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 morning dosage if there are concerns about compliance and toxicity. No routine indication.
  • Monitor for signs of hepatotoxicity.