Helpful tips for using pharmaceuticals with kids

October 1, 2017
Jon Matthew Farber, MD

Dr Farber is a pediatrician in Woodbridge, Virginia.

Children are not little adults, and it’s only common sense to be aware of a child’s age and weight when dosing pharmaceuticals. Here are some other helpful gems I’ve uncovered about medications.

1. When there is unclear information on pediatric dosing, an adult can be thought of as someone who weighs 40 kg (88 lb). Thus, a 100-lb, healthy 10-year-old child can usually be given an adult dose of medicine, and a 22-lb toddler could be given one-fourth of the adult dose.

2. Focalin XR releases faster than Concerta (Cmax1 1.5 h vs 3.7 h, respectively), according to the manufacturers.

3. You cannot open up Concerta and sprinkle it. The time release is in the delivery system (a piston that pushes the active ingredient through a tiny hole), and is not due to individually coated beads of medicine with different absorption rates, as with most other extended-release medicines.

4. As a rough guide, to convert Vyvance to Adderall XR, subtract 10 and divide by 2; eg, Vyvance 30 mg is equivalent to (30-10)/2=10 mg Adderall XR. As such, 2 Vyvance 30 mg are equivalent to Vyvance 50 mg, not 60 mg. This conversion, of course, does not work for the 10-mg Vyvance.

NEXT: Knowing about the basic workings of pharmaceuticals


5. Know the classes and basic workings of medicines you use. For example, if the combination of dex- and levo- (which is felt to be inactive) methylphenidate (eg, Concerta), is causing adverse effects, switching to just dexmethylphenidate (eg, Focalin XR) does not make sense.

6. Similarly, if ketotifen (an antihistamine and mast cell stabilizer) eye drops have not helped with allergies, changing to olopatadine (another antihistamine and mast cell stabilizer) may not be the best choice. Ketorolac, a nonsteroidal anti-inflammatory, might provide better relief.

7. However, there are times when changing within a family is reasonable. I would still try dextroamphetamine for attention-deficit/hyperactivity disorder (ADHD) if methylphenidate did not work, or go from one selective serotonin reuptake inhibitor (SSRI) for depression to another if the first one was unsuccessful. Part of the reason is that, for ADHD and depression, these classes of medicine are clearly the best options, whereas that distinction is not as true for allergic conjunctivitis.

8. We are told not to give sulfa to babies because it can displace bilirubin in the bloodstream. However, sulfa eye drops are acceptable; the amount of medicine would not have clinical effects on bilirubin.

NEXT: What about codeine?


9. When I first started in pediatrics, I used a fair amount of codeine, both for pain (our only nonnarcotic option at the time was acetaminophen) and cough (in which it probably worked mostly by sedating), and it also helpfully came in a liquid. Nowadays, codeine use is very simple: DON'T DO IT. There are adverse effects, many children are rapid metabolizers, and it will be ineffective Ibuprofen works as well.1

10. Don’t use oral ketoconazole. It has a black box warning.

11. Children’s probiotics often have added sugar. If you wish to avoid this, you can open up adult capsules without sugar and use those instead.

12. Be clear on your instructions when telling a family to give 2 puffs of an inhaler. I have known them to do puffs back-to-back with a spacer, then have the child breathe, rather than 1 puff, 6 or more breaths, and repeat (perhaps after waiting one minute), which is the preferred method.

13. Cefdinir can turn the stools red. Parents will assume this is blood, but it is not quite the right color, and a hemoccult test will be negative. This is an adverse effect, not an allergy, and the medicine can be continued.


1. Tobias JD, Green TP, Coté CJ; Section on Anesthesiology and Pain Medicine; Committee on Drugs. Codeine: time to say “no.” Pediatrics. 2016:138(4);e20162396.