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

Travel medication checklist

When travelling, I like to bring along medication to relieve symptoms of common illnesses. This is useful for the following reasons:

1)       Medical help may not be available especially when travelling on a long flight or by sea, including geographically remote areas

2)       Medicines may be classified differently in foreign countries such that our usual over-the-counter medicine may require a prescription (a visit to the local doctor) to purchase.

3)       The usual combination drugs or brand names that we are used to may not be always available; and of course lastly

4)       If limited English is used in the foreign country, it would be very hard to get the right medication.

Below is my travel medication checklist:

Adult
Symptom	Medicine
Diarrhea	Charcoal tab
Gastric pain	Antacid
Headache/fever	Paracetamol
Runny nose	Cetirizine
Children
Symptom	Medicine
Diarrhea/loose stool	Lacteofort
Fever	Paracetamol / Ibuprofen
Runny nose	Fedac / Actifed

I would bring along only medicines that I have used before to prevent any ‘surprise’ reactions that may accompany unfamiliar medicines.

Fedac (or Actifed) dosage to relieve the common cold

Fedac (or Actifed) is the brand name of a combination product of Triprolidine 1.25mg/5mL and Pseudoephedrine 30mg/5mL. Triprolidine is an antihistamine that helps stop sneezing, runny nose and watery eyes (like blocking a leaky tap!) Pseudoephedrine is the decongestant component that relieves nasal congestion and blocked sinuses (opens a choked tap!). These symptoms can be present either singly or in combination when one catches a cold or flu. I know, it doesn’t make sense to have blocked nose and runny nose at the same time, but it does happen, not at the exact same minute (hour) but they can present at different times of the day. Hence, these two ingredients are commonly prescribed together.

How much to take?

Adults and children over 12 years: 10ml

Children 6 - 12 years: 5ml

Children 2 - 5 years: 2.5ml

Below two years: As recommended by doctor ( My #3 who was 1.5 yrs old and 10kg was prescribed 1.5mL)

Doses to be taken 8 hourly.

As the weight for children 2 to 5 years old is wide, I prefer to use the dosage by weight based on Pseudoephedrine.

Weight (kg)	Volume Fedac (mL)
8	1.3
9	1.4
10	1.5
11	1.7
12	1.8
13	2.0
14	2.1
15	2.3
16	2.4
17	2.6
18	2.8
19	2.9
20	3.0
21	3.2
22	3.4
23	3.5
24	3.7

It is common to experience drowsiness after taking Fedac, hence what I usually do is to give it to my child only at night if the symptoms are not severe. This medicine is just a symptom reliever after all and the body will have to fight the cold/flu on its own.

Ibuprofen dosage chart by weight

I don’t take ibuprofen, probably because paracetamol is good enough and works for all my fever and headaches. Ibuprofen belongs to the same class of drugs as aspirin, mefenamic acid, naproxen sodium and diclofenac – they are NSAIDS (pronounced as 'and-saids') – non-steroidal anti-inflammatory drugs. Since inflammation results in pain and/or fever, thus these drugs treat pain and fever by reducing inflammation. They are the second choice if paracetamol does not work well probably because these drugs may cause gastric discomfort (though newer generation NSAIDS have lesser risk of this). That’s why it is usually recommended to take after food or together with antacids.

My mom is allergic to paracetamol thus she takes mefenamic acid for all her fever and pain. My husband is allergic to diclofenac and avoids this but he had used diclofenac cream before (unknowingly once) and showed no signs of allergy.

I give my children ibuprofen syrup when their fever is not well controlled i.e. fever comes back before the next dose (6 hours later) or high fever (temperature more than 39°C. I am guilty of sometimes giving ibuprofen to my children because they refuse to take Paracetamol, the strawberry flavoured syrup is too bitter, they like the ‘orange colour’ ibuprofen syrup. The alternating ibuprofen-paracetamol dosing every 4 hourly is also a good way to control fever, this has been reported in a clinical trial¹ to be better than using either on its own.

There is a note of caution for ibuprofen - Do not use in infants less than 1 year old, unless advised by your doctor.

The oral dosage for fever is 5 to 10 mg/kg body weight. To be taken every 6 to 8 hours, not more than 4 doses a day. Like my earlier post on paracetamol dosage by weight, I too have a chart for ibuprofen dosage by weight.

If you’d wish to use this chart, here is a step-by-step guide.

1. Weigh your child, measurement should be in kilograms (kg). To convert from Pounds (lb), divide by 2.2.
2. Check the strength of your Ibuprofen syrup. Some clinic assistants do not label the strength, always ask. This syrup is most commonly available in the 100mg/5mL strength
3. Refer to the chart for the corresponding volume. You may give an amount between the lower and upper limit.
4. Shake the bottle to disperse the liquid and draw the correct volume using a syringe.

Common trade names for Ibuprofen are Brufen, Advil, Nurofen. If there are more, please leave a comment.

Reference

1. Paracetamol and ibuprofen for the treatment of fever in children: the PITCH randomised controlled trial. Health Technol Assess. 2009 May;13(27):iii-iv, ix-x, 1-163.

Paracetamol dosage chart by weight

Someone from the army once told me "Take Panadol (paracetamol), it will cure your illness if you are sick, if you are not sick, it will boost your health". That statement of course is not true but was probably meant as a cynical joke to how commonly prescribed this medicine is.

The adults in my home use it to treat fever and headache. Yes I have a policy that at the slightest headache, don't wait, don't sleep it off, it will not get better, just take two 500mg tablets, period.

I give my children paracetamol to treat fever, when temperature is more than 37.5°C. I would fumble with the phone calculator, checking to make sure that I give the correct volume according to the strength of the medication and the dose by body weight. After countless times doing this, with my third kid turning one soon, it just dawned on me that I should just make a chart and refer to it. So here it is and this gets printed, sealed in a plastic sheet and placed in the medicine cabinet. And my husband no longer needs to guess and estimate the right dose to give.

Why is the right dose important?

Too little and it will not be effective, the fever will not subside. Too much (this amount is very high) and it may cause harm to the liver.

The oral dosage for fever is 10 to 15 mg/kg body weight, not more than 3750 mg/day

To be taken every 4 to 6 hours, not more than 5 doses a day.

When my child develops fever before the 6 hours is up, I will then supplement with ibuprofen, more about this later.

At the correct dose, the fever should subside within 1.5 to 3 hours.

If you’d wish to use this chart, here is a step-by-step guide.

1. Weigh your child, measurement should be in kilograms (kg). To convert from Pounds (lb), divide by 2.2.
2. Check the strength of your Paracetamol syrup. Some clinic assistants do not label the strength, always ask. Common syrup strengths are 120mg/5mL and 250mg/5mL.
3. Refer to the chart for the corresponding volume. You may give an amount between the lower and upper limit.
4. Shake the bottle to disperse the liquid and draw the correct volume using a syringe.

Common trade names (brands) of Paracetamol are Panadol, Dhamol, Tylenol. If there are more, please leave a comment.