Methylphenidate
Class: central stimulant – amphetamine related
Indications (NB some may be unlicensed): attention deficit hyperactivity disorder (possible restrictions), narcolepsy, depression in palliative care, neurobehavioural symptoms in brain tumours /injuries
Contraindications/cautions: anxiety, glaucoma, agitation, hyperthyroidism, severe cardiac disease, hypertension, epilepsy
Adverse reactions: common: nervousness, insomnia, tachycardia, urticarial, GI effects; less common: blurred vision, hallucinations, blood disorders, psychosis (very high doses), arrhythmias
Metabolism/clearance: metabolised by hydrolysis. Inactive metabolite is excreted by the kidneys
Interactions:
- increased analgesia and decreased sedation may occur with some opioids
- hypertensive crisis may occur with concomitant MAOIs (e.g. tranylcypromine)
- decreased hypotensive effect of adrenergic blockers (e.g. terazosin) may occur with concomitant methylphenidate
- hypertension with tricyclic antidepressants (e.g. amitriptyline) may occur
| Dosing: | depression (max. adult dose of 1 mg/kg/24 hours) |
|---|---|
| oral: | normal release 10 to 30 mg a day (morning and mid-day) Commence with 2.5 to 5 mg twice daily (morning & noon) – increase in 2.5 mg increments to 20 mg twice daily if necessary. Max 30 mg twice daily |
| subcut: | not available |
| rectal: | not available |
Syringe driver: not available
Mechanism of action: acts as a stimulant in the CNS
Onset: depression: 2 to 5 days
Notes:
- patients may respond to short courses of 2 to 3 weeks then withdraw
- methylphenidate is occasionally used to treat opioid-induced drowsiness