Dosage of HU for thal Intermedia of 4 yrs, 15Kgs

Hi all,
I am a new member having a kid of four years diagnosed with Thal Intermedia(HB-E Beta). He has been on HU(Hydrea) for nearly nine months. The treating doctor started initially with 500mg thrice a week(Mon,Wed, Fri). The Blood count (Hb) was noticed as elevated to 8.5 from 6.5. But recent two CBC shows a dip in the result and reached to 6.7 again.

I came across few statements as "Prolonged responses were achieved with low doses of HU (3–10 mg/kg/day) and higher doses were associated with mild reversible hematologic or hepatic toxicity and no further increases in Hb."
"Adverse effects were more common in group B, making this dose (20 mg/kg/day) of HU more myelo-suppressive than Hb F inducing."

My child’s weight is 15 Kg so as per the calculations (considering minimum dose of 10mg/kg/day), I guess he should be given 150mg/day (1050 mg/ week) whereas currently, he is having 214mg/day(500mg>Mon, Wed, Fri=1500mg/ week).Therefore,(1500-1050=450 mg/ week was excess in his dose). Now Doctor has reduced the dose to 178mg/day(250 mg> Mon to Fri). Thus, 1250-1050=200 mg/ week excess he will be having now.

I hereby seek all yours valuable advices on:
1.Is the current dosage is appropriately given with his age or that needs to be minimized further (with exact 150 mg/day or lesser).
2.If toxicity has happened, Is the treatment need a break of 15 days as I am informed in some statement
"If toxicity occurs, treatment will be stopped for at least 1 week and until toxicity resolves. HU will then be resumed at the same dose or a dose decreased by 2.5-5 mg/kg/d. If toxicity does not recur after 12 wks on the lower dose, the dose may then be increased by 2.5-5 mg/kg/d. If toxicity recurs on the higher dose, then HU will be stopped again until toxicity resolves, and hydroxyurea can then be resumed at the lower dose."
3. Sat and Sundays are excluded from the dosage dates.Is there somewhere the spontaneity of the medicine is lost.
4. How to get the capsule powder in 150 mg proportions that comes in 500 mg as a whole.

Hi Mithun,

I've seen no study that shows a benefit to taking more than 15 mg/kg day. I don't think raising the dose above 10 mg/kg will harm, as long as it stays below 15.
The toxicity statement is correct. But has toxicity been shown in this case? There can be other reasons why Hb drops, like illness or exposure to certain foods or chemical fumes.
Many patients are told to take the drug 5 days a week. I believe this is to reduce potential toxicity. I do always suggest that wheatgrass be taken in some form along with hydroxyurea, and this should be taken 7 days a week. This will help maintain continuity, but I don't think skipping weekends interrupts it much anyway.
The last question you would have to get answered depending on what forms of the drug is available to you.

Hi Andy,
Seems the dose is pretty fine for now. I am just trying to find the causes for the drop of Hb as he didn't fall sick or any problems with food or climate is noticed. I have been giving him Wheatgrass juice freshly planted in pots and raw juice mixed with water equally half of glass every alternate days. I thought, the wheatgrass is conflicting with the result so I stopped for two months. Now, I will start on this for everyday as you suggested. Toxicity part, I need to confirm from my Doctor.
Hydrea 500mg Capsule is only available and 250mg he is having 5  days a week now.

Thanks Andy for your directions..and looking forward to your further guidance as I shall keep you updated with the results.