Ritalin vs Medikinet MR vs Concerta

Methylphenidate (MPH) is the most prescribed psychostimulant for ADHD treatment. It works by blocking the dopamine and norepinephrine transporters, thereby increasing synaptic dopamine and norepinephrine concentrations (which is said to be lacking in ADHD-diagnosed individuals). Oral effective doses of 0.25 and 1 mg/kg are estimated to being able to, respectively, block 50% and 75% of the dopamine transporter ^1,2. On the other hand, a dose of 0.5 mg/kg will delay sleep start time and decrease sleep duration ³, hence care should be observed on doses near bedtime.

As Methlyphenidate has a short duration of action, other dosage forms have emerged to prolong its effect especially when multi-dosing throughout the day is not possible. Below is the table of comparison on three commonly used brands. While benefits are observed during duration of action, unwanted side effects such as decreased appetite is also observed for the duration of the drug. For example, someone taking Concerta may not have appetite for the entire 12 hours.

Brand name	Ritalin 4	Medikinet 5	Concerta 6
Release Type	Immediate (IR)	Modified (MR)	Extended Release
Composition	100% Immediate release	50% IR, 50% from enteric coated pellets	22% IR, 78% from Osmotic Release
Dose equivalent to IR	N.A.	10 mg is for equivalent to 5 mg, 5 mg twice dosing	18 mg is for equivalent 5 mg, 5 mg, 5 mg thrice dosing
Time to peak (hours)	1-2	1st: 1-2 followed by 3-4 h plateau concentration phase whereby peak concentration does not fall below 75%	1st: 1-2 2nd: 6-8
Duration (hours)	3-4	3-8	3-12
Effects by meal	No effect on absorption. Can be taken with or without food.	On an empty stomach, the absorption rate is faster and extended release may not be adequately sustained. Should be given after a meal.	No effect on absorption. Can be taken with or without food.
Plasma levels after 24h	Close to zero, hence no accumulation	Close to zero, hence no accumulation

References:

1. Volkow ND, Wang GJ, Fowler JS, Gatley SJ, Logan J, Ding YS, Hitzemann R, Pappas N: Dopamine transporter occupancies in the human brain induced by therapeutic doses of oral methylphenidate. Am J Psychiatry 155:1325–1331, 1998
2. Spencer TJ, Biederman J, Ciccone PE, Madras BK, Dougherty DD, Bonab AA, Livni E, Parasrampuria DA, Fischman AJ: PET study examining pharmacokinetics, detection and likeability, and dopamine transporter receptor occupancy of short- and long-acting oral methylphenidate. Am J Psychiatry 163:387–395, 2006
3. Santisteban JA, Stein MA, Bergmame L, Gruber R: Effect of extended-release dexmethylphenidate and mixed amphetamine salts on sleep: A double-blind, randomized, crossover study in youth with attention-deficit hyperactivity disorder. CNS Drugs 28:825–833, 2014
4. Ritalin Summary of Product Characteristiscs Health Products Regulatory Authority November 2023
5. Medikinet Summary of Product Characteristiscs Health Products Regulatory Authority January 2024
6. Concerta Summary of Product Characteristiscs Health Products Regulatory Authority November 2022