# Methylin ### (methylphenidate hydrochloride, immediate-release) **[Methylin](https://wiki.joshnp.com/books/drug-library/page/methylin)** (methylphenidate hydrochloride, immediate-release); CII
[**Full Prescribing Information**](https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=9e3c22d9-71d9-46a7-b315-8021c94c4bec&type=display)[**DailyMed Drug Information**](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9e3c22d9-71d9-46a7-b315-8021c94c4bec)
--- ### **Summary** Methylin is immediate-release methylphenidate supplied as a grape-flavoured oral solution, approved for ADHD in patients 6 years and older and for narcolepsy, with generic chewable tablets at 2.5 mg, 5 mg and 10 mg. Its differentiator is dose granularity for a child who cannot swallow: the solution measures to fractions of a milligram, which no tablet in the class can do. Schedule II; oral solution brand and generic, chewable tablet generic only. --- ### **Forms & Strengths** - Oral solution (grape, colorless): 5 mg/5 mL and 10 mg/5 mL - Chewable tablets (grape): 2.5 mg, 5 mg, 10 mg --- ### **Dosing** - **Age:** - ADHD: >= 6y - Narcolepsy: no age floor - **Onset:** ~ 1 hour - **Duration:** 3 to 4 hours - **Initial Dose:** - >= 6 y/o and older: 5 mg twice daily, before breakfast and before lunch - Adults: 20 to 30 mg daily in 2 or 3 divided doses, 30 to 45 minutes before meals. - **Titration:** 5 - 10 mg every 7 days - **Max Dose:** 60 mg/day - **Considerations:** The chewable tablet must be taken with at least 8 ounces of fluid because it swells and can cause choking, and it contains phenylalanine. --- ### **Pharmacology** - **Mechanism:** Blocks presynaptic dopamine and norepinephrine reuptake at DAT and NET; does not meaningfully promote catecholamine release at therapeutic doses - **Delivery / Release:** Immediate release, no modified-release component in either form. Solution and IR tablet are near-bioequivalent at 20 mg. - **Metabolism:** De-esterified to ritalinic acid, essentially inactive. Protein binding 10% to 33%. Mean terminal half-life 2.7 hours, the shortest methylphenidate in this library. - **Food effect:** a high-fat meal raises solution Cmax ~13% and AUC ~25% and delays Tmax by about an hour, a smaller effect than on [Metadate CD](https://wiki.joshnp.com/link/24). - **Class Positioning:** The only methylphenidate titratable in fractions of a milligram, and the most reversible. Compare [Ritalin](https://wiki.joshnp.com/link/29) (IR tablet) and [QuilliChew ER](https://wiki.joshnp.com/link/27), an extended-release chewable not to be confused with this one. --- ### **Indications** - **ADHD** (ICD-10: F90.0, F90.1, F90.2, F90.8, F90.9): patients 6 y/o and older, and adults - **Narcolepsy** (ICD-10: G47.419): no age floor --- ### **Off-Label Uses** - **ADHD in children 4 to 5 years old** (ICD-10: F90.x): behavioral therapy first line; IR methylphenidate from a low dose where it fails. Expert consensus. (AAP 2019) - **Afternoon top-up alongside a long-acting methylphenidate** (ICD-10: F90.x): coherent given the 3 to 4 hour window; 60 mg/day ceiling applies to the sum. Limited data. (AHRQ 2024) - **Where the evidence does not support use:** binge eating disorder (F50.2), treatment-resistant depression (F33.9), cancer-related and other fatigue (R53.0, R53.83). Adult literature only; insufficient in children. (AHRQ 2024) - **Cognitive enhancement in a youth without ADHD:** not an indication and not supported. --- ### **Contraindications & Warnings** - **Boxed Warning:** Abuse, misuse and addiction, with overdose and death; risk rises with dose and non-oral routes. Assess abuse risk before prescribing and reassess throughout. - **Contraindicated:** - Hypersensitivity to methylphenidate or any component - MAOI use, current or within 14 days: hypertensive crisis - Chewable tablet only: difficulty swallowing. Use the oral solution. - **Use with caution:** - Structural cardiac abnormality, cardiomyopathy, serious arrhythmia or coronary disease: avoid - Pre-existing hypertension: monitor blood pressure and pulse - Psychotic or bipolar disorder: exacerbation and treatment-emergent mania - Significant hyperopia or angle-closure risk: refer to ophthalmology - Personal or family history of tics or Tourette's syndrome - Phenylketonuria, chewable only: 0.42 / 0.84 / 1.68 mg phenylalanine per 2.5 / 5 / 10 mg tablet - Substance use disorder in patient or household; a 500 mL CII bottle is hard to audit - **Screen before starting:** - Cardiac history and exam including family sudden death; the label requires the screen, not an ECG - Tics, mania risk factors, and abuse or diversion risk in patient and household - Swallowing ability, which decides the form; PKU if a chewable is considered - Baseline height, weight, BP and HR --- ### **Drug Interactions** - **MAOIs** (phenelzine, tranylcypromine, selegiline, linezolid, methylene blue): hypertensive crisis. Contraindicated within 14 days. - **Antihypertensives:** effectiveness reduced. Increase BP monitoring and adjust the antihypertensive. - **Halogenated anesthetics** (sevoflurane, isoflurane, desflurane): intraoperative BP and HR surge. Hold all doses on the day of surgery. - **Risperidone:** EPS may increase when either dose changes in either direction. Monitor across any titration. - **Serotonergic agents** (SSRIs, SNRIs, TCAs, triptans, tramadol): serotonin syndrome in postmarketing reports only. Counsel on symptoms rather than avoiding. - **Venlafaxine:** one pediatric NMS-like report after a first dose. Watch the first days of any new serotonergic agent. --- ### **Administration** - Give 30 to 45 minutes before meals, which is a labeled instruction. - Before breakfast and before lunch; add a third dose for afternoon coverage. Last dose before 6 p.m. if sleep is affected. - **Oral solution:** measure with an oral syringe or calibrated cup, never a kitchen spoon. The two strengths look identical; state the concentration on every prescription. - **Chewable tablet:** chew well, swallow with at least 8 ounces of fluid; it swells and can obstruct the throat. - Missed dose: give only if the next is several hours away and it is not late. Never double up. - Store locked. A flavoured CII liquid is the form a younger sibling is likeliest to drink. --- ### **Side Effects** - **Common:** tachycardia, palpitations, headache, insomnia, anxiety, hyperhidrosis, decreased appetite, weight loss, dry mouth, nausea, abdominal pain. No pediatric percentages published. - **Serious:** - Choking or esophageal obstruction from a chewable taken dry: emergency, unique to that form - Sudden death with structural cardiac disease: avoid in that population - New psychosis or mania, including with no psychiatric history: consider discontinuing - Priapism, sometimes surgical, including during drug holidays and withdrawal - Peripheral vasculopathy and Raynaud's with digital ulceration: assess digits each visit - Long-term growth suppression; angle-closure glaucoma; new or worsening tics - Postmarketing: seizures, dyskinesia, cerebral arteritis, hepatic injury, leukopenia, thrombocytopenic purpura, erythema multiforme, rhabdomyolysis, NMS --- ### **Monitoring & Labs** - **Concentration and measuring device:** confirm at every visit and refill; the twofold strength difference is this page's likeliest dosing error. - **Adherence:** confirm at every visit that the midday dose is given; a missed school dose mimics loss of efficacy. - **Growth:** height, weight and BMI at baseline and every 6 months; every visit if losing weight. - **Cardiovascular:** BP and HR at baseline, at every dose change, and at least every 6 months. - **Appetite and sleep:** at every visit and dose change; ask the time of the last dose. - **Psychiatric and tics:** screen for psychosis, mania, aggression, depressed mood and tics at baseline and every visit. - **Abuse and diversion:** at every refill, ask about sharing and selling and check the PDMP. Reconcile volume remaining against days elapsed; a bottle cannot be pill-counted. - **Laboratory:** none required. Check liver enzymes only for jaundice, dark urine or unexplained abdominal pain. --- ### **Discontinuation & Taper** - No taper required; neither label gives a tapering schedule. - Discontinue if no improvement after appropriate dose adjustment over one month. - Withdrawal after prolonged use: dysphoria, fatigue, vivid dreams, sleep change, increased appetite. - Priapism has occurred during drug holidays and on discontinuation. - Drug holidays are easiest here: the solution can be part-dosed as well as part-scheduled. --- ### **Pregnancy & Lactation** - **Pregnancy:** no drug-associated risk of major birth defects or miscarriage identified. Stimulant vasoconstriction may reduce placental perfusion. Background risk 2% to 4% and 15% to 20%. Weigh against untreated maternal ADHD. - **Lactation:** infant dose 0.16% to 0.7% of the maternal weight-adjusted dose; undetectable in infant plasma in every reported case. Not a reason to stop breastfeeding. (LactMed 2025) - **Lactation, milk supply:** prolactin falls; large doses may interfere before supply is established. Monitor the infant for agitation, insomnia and poor weight gain. (LactMed 2025) - **Exposure Registry:** National Pregnancy Registry for Psychostimulants, 1-866-961-2388. --- ### **Counseling Points** - **Counsel the family on:** - The two concentrations: the same 5 mL is 5 mg or 10 mg depending on the bottle. Check every refill, and measure only with the supplied syringe. - The chewable needing a full 8 ounce glass every time; chewed dry it swells and can block the throat. - The 3 to 4 hour window: the lunchtime dose is part of the plan, not a sign the first failed. - Rebound irritability and hunger several times a day: expected, not a reason to raise the dose. - Locking up the bottle; a flavoured CII liquid is the easiest form to lose unnoticed. - Bringing a teacher rating scale, morning and afternoon rated separately. - **Advise them to call for:** - Chest pain, vomiting or trouble swallowing after a chewable: emergency - Chest pain, fainting, or a racing heart that does not settle - New hallucinations, or new suspicious or fearful thinking - Numbness, coldness or colour change in fingers or toes, or a sore that will not heal - A new or markedly worse tic, including throat clearing and blinking - A painful erection lasting more than a few hours, including during a break - Any amount of the solution swallowed by another child in the house --- ### **References** 1. DailyMed. Methylin (methylphenidate hydrochloride) oral solution prescribing information. Shionogi Inc. 2023. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9e3c22d9-71d9-46a7-b315-8021c94c4bec 2. DailyMed. Methylphenidate hydrochloride chewable tablets prescribing information. Lupin Pharmaceuticals. 2023. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5bfe50ed-171f-4c40-bc0b-20c68e8e2025 3. FDA. openFDA National Drug Code Directory, generic\_name methylphenidate. 2026. https://api.fda.gov/drug/ndc.json?search=generic\_name:%22methylphenidate%22&limit=1000 4. LactMed. Methylphenidate. Drugs and Lactation Database, NICHD. 2025. https://www.ncbi.nlm.nih.gov/books/NBK501310/ 5. American Academy of Pediatrics. Clinical practice guideline for the diagnosis, evaluation, and treatment of ADHD in children and adolescents. Pediatrics. 2019. https://publications.aap.org/pediatrics/article/144/4/e20192528/81590/ 6. AHRQ. Attention deficit hyperactivity disorder: diagnosis and treatment in children and adolescents. Comparative Effectiveness Review No. 267. 2024. https://www.ncbi.nlm.nih.gov/books/NBK602989/