Hi Nadia,
The dosage of sodium phenylbutyrate increases with weight. The dose is based on mg/kg per day of body weight, so as one increases in weight,the dosage increases. Once the individual gets to a certain age and weight, the dose is then calculated on grams/meterssquared (sorry, can't type a superscript 2 on this) so that you are dosing body fat. For example, if you had a child or adult that was 10 pounds overweight, if you used the mg/kg/day of body weight calculation, the child would get too much drug. The grams/meterssquared calculation calculates body surface area so that the dosage is more precise. The dose is also dependent upon the individual's own enzyme activity -- the less urea cycle enzyme activity the individual has, the more drug they have to take. (So, the more severe mutation, the more drug required to help them remove ammonia). The adults take up to even 40-50 tablets a day. The reason we worked so hard to have HPN-100 developed was to ease the burden of administering the drug (G-tubes, NG-tubes, taste of the powder, number of pills, etc.) and to have less side effects than sodium phenylbutyrate. Once HPN-100 is approved in the U.S., we will be pushing to get it approved in the UK and Europe as soon as possible. Give sweet A. a hug from me. Best,
Cindy (NUCDF)