Weight before age, when it comes to dosage

By Salma Yusuf

How a child grows varies from child to child as parents well know. While one five-year-old may be rather plump, well above the average weight for his/her age, another may be small and thin. And yet when it comes to medicine, they are both five-year-olds.

Taking such variations into consideration, leading pharmaceutical manufacturer GlaxoSmithKline (GSK) has launched a new paediatric dosage chart for Paracetamol products based on weight rather than age. For many years, paediatric dosing was carried out based on age, but the current thinking is that dosage by weight is more appropriate than dosing by age.

For over a year, a 15-member advisory panel including renowned paediatricians in the country and pharmacologists from the University of Colombo, Dr. Dennis Aloysius, Dr. Nanda Amerasekera, Dr. J.V. Ariyasinghe, Professor Dayasiri Fernando, Dr. Maxie Fernandopulle, Professor Rohini Fernandopulle, Professor S.P. Lamabadusuriya, Dr. B.J.C. Perera, Dr. Shalini Sri Renganathan, Dr. Ajitha Wijesundera, Dr. Anula Wijesundera, and Dr. Lakshman Weerasena with assistance from the Medical Research Institute carried out extensive analysis and deliberations to develop a dosage chart based on weight for the paediatric range of the company's flagship brand Panadol.

This was also done in the light of background studies and findings from countries all over the world, Brand Manager for GSK, Saroshika Jayawardena told The Sunday Times.

Dr. Lucian Jayasuriya

"Paediatric dosage based on weight is a method that is followed by many countries in the world and is effective. In Sri Lanka, however, since most of the data was not readily available, much analysis and consultation had to be done to arrive at the new dosage system based on weight," GSK spokesman, Dehan Seneviratne, Director Corporate Affairs and Medical Marketing said.

The new dosage chart introduced by GSK has been approved by the Sri Lanka Drug Regulatory Authority. The DRA has made it the standard dosage system for all paediatric Paracetamol products in the country. "Panadol for Children is a household name and our primary concern is to ensure that children are given the proper dosage for effective treatment, " the company's spokesman said.

The new paediatric dosage chart by GSK was unveiled at a medical symposium held in Colombo recently. 'Panadol for children' , Panadol's paediatric range, was also re-launched at the event with new packaging designed in compliance with the recent policies set by the Sri Lanka Drug Regulatory Authority.

Speaking to MediScene Medical Advisor for GSK, Dr. Lucian Jayasuriya, said, "Prior to this new system being introduced, the problem with the dosing by age gave rise to a two-fold problem. The first was that in the event the child was of a higher weight than that of the average child of the same age for which the dose was prescribed, it would result in an under-dose of the medication and thus the child will not be cured. This would obviously cause anxiety in the mother who would then give the child another dose which would result in an over-dosage, the effect of which could give rise to a host of other problems in the child.”

This is why dosage by weight is more accurate than dosage by age, he said.

One of the problems encountered in putting this system in place is the fact that many parents know the weight of their child only upto the age of one year because of regular check-ups and visits to the paediatrician. Thus, Dr. Jayasuriya recommends that the mother should weigh the child as a solution to this problem. 'For practical purposes, we have formulated a chart giving the age of the child, the corresponding average weight and the prescribed dosage.’

Dr. C. Piyasena from the MRI had also worked extensively on the project collecting data from 4709 households, 8000 children across 17 districts to arrive at the average weights for a given age range where the upper and lower centiles were looked at.

The expert panel took the following factors as crucial in arriving at their conclusions-

The necessity to keep the dosage simple; provision of satisfactory devices for accurate measurement of the selected dosage (spoon, cup, tube, syringe etc) and the desire to satisfy the needs of a multi-ethnic, multi-lingual society in terms of equal emphasis given to instruction labels on the packaging.

The Office of Medical Technology & Supplies issued the new dosing schedule at the end of last year and gave a six-month period from January 1, 2006 for implementation to all market authorization holders of Paracetomol paediatric preparations.