methylphenidate RITALIN
Class: StimulantFDA Indications: ADHD, Narcolepsy
Off-Label Use: Depressive Symptoms In Medically-ill Elderly, Cancer-related Fatigue, Depression (adjunct)
Prescribing
FDA Schedule IIForms: 5, 10, 20mg IR tablets; mg wax matrix tabs i.e. Metadate ER–20mg, Ritalin SR–10,20mg; 24° cap (Aptensio XR–10,15,20,30,40,50,60mg); 25mg/5mL suspension (Quillivant XR); OROS formations (Concerta–18,27,36,54mg); Diffucaps (Metadate CD)–10,20,30,40,50mg; SODAS formations i.e. Ritalin LA–10,20,30,40mg ; 10mg/5mL & 5mg/5mL po soln; Transdermal–Daytrana (10,15,20,30mg per 9°)
Dose Range: 10-60 mg/day
Starting: IR formulations–5 mg bid (before breakfast & lunch); titrate to effect; max dose 60 mg daily in divided doses
Monitoring: Periodic CBC, differential, and platelet counts are advised during prolonged therapy; also monitor BP & HR
Precautions
Contraindications: Severe HTN, heart failure, arrhythmia, hyperthyroidism, thyrotoxicosis, pheochromocytoma, recent MI or angina, concomitant use of halogenated anestheticsSerious Side Effects: Serious cardiovascular events. Sudden cardiac death, stroke, and MI. Can exacerbate pre-existing bipolar or psychotic disorder. May lower seizure threshold.
Drugs to Avoid in Congenital Long QT
Side Effects: headache, insomnia, irritability, decreased appetite, nausea, xerostomia, emotional lability, hyperhidrosis, weight loss, priapism, peripheral vasculopathy
Pharmacodynamics
1° MOA: Promotes presynaptic DA & NE releaseTarget: NET & DAT, Postsynaptic 5HT1A (weak)
Pharmacokinetics
t½: 2.8° TMAX: 1-2°Substrate of: CES1
Inhibits: ∅ ; Induces: ∅
Active Metabolites: ∅
DDIs
- - avoid with MAO inhibitors
- - may ↓ effectiveness of antihypertensives
- - because of possible effects on BP, use with caution with pressors
- - be aware of possible pharmacodynamic interactions with other dopaminergic agents (DA agonists and antagonists)
Misc
- - short-acting (Ritalin); onset ~20-60 min; duration ~3-5°
- - intermediate-acting (Metadate ER, Ritalin SR); onset ~20-60 min; duration ~8°
- - long-acting OROS (Concerta) — 22% IR / 78% ER
- - long-acting Diffucaps (Metadate CD)— 30% IR / 70% ER
- - long-acting SODAS (Ritalin LA)— 50% IR / 50% ER
- - the d-isomer is the therapeutically active compound
- - unlike amphetamine, methylphenidate does not promote DA release from synaptic vesicles
Special Populations
Category C—Although the animal data suggest moderate risk, the limited human pregnancy experience prevents a better assessment of the embryo-fetal risk. Neither the isolated cases of structural defects nor the outcomes observed with methylphenidate abuse are suggestive of methylphenidate-induced developmental toxicity.
RID 0.7%; very limited human data; potential toxicity within first month, during which nursing mothers should watch for signs of CNS stimulation, i.e. decreased appetite, insomnia, and irritability
Start lower, i.e. 10 mg/d (typical dose is 20 mg/d); consider a 5 mg/d starting dosage for especially frail patients; give second dose mid-afternoon to avoid insomnia
No dose adjustment necessary
No dose adjustment necessary