Medicine dosage at the cusp of age brackets

[KanyesVest]

DD was 5 in June. She's about 18kg so fairly well settled in the middle if the weight bracket. She has a dose of chicken pox that started on Wed/Thurs but we only realised was chicken pox on Friday. She's pretty miserable this evening but so far I've stuck to the 2-5yrs dosage of antihistamine, which is 2x2.5 ml over 24hrs. If she was 6, I could give her 2x5ml doses. Would she turn into sleeping beauty if I gave her an extra 2.5ml during the night if she needed it? I'm a real stickler normally, but she's itchy and miserable and it seems such a big difference in just 7 months...

Its only a vague guide, it really makes no difference at all.

I'd give her a little extra just for the night dose.

I wouldn't with an antihistamine, and definitely not at night, as they can depress breathing. I know there's a huge safety margin, but this is not one I'd play fast and loose with.

Oh, really, Stella? I didn't know that. It's zirtek which is one of the less drowsy ones...

Children 2 to 5 Years: The recommended initial dose of ZYRTEC (cetirizine) in children aged 2 to 5 years is 2.5 mg (½ teaspoon) syrup once daily. The dosage in this age group can be increased to a maximum dose of 5 mg per day given as 1 teaspoon syrup once a day or one ½ teaspoon syrup given every 12 hours, or one 5 mg chewable tablet once a day.

This might help

NHS website says there is a stronger medicine to ease the itching

'A stronger medicine called chlorphenamine can also help to relieve the itching. It's available from your pharmacist over the counter or it can be prescribed by your GP. Chlorphenamine is taken by mouth and is suitable for children over one year old.'

Try your local chemist?

Is chlorphenamine not piriton? Piriton is good for chickenpox itching as it is a sedating anti histamine

When you get issued medicine (e.g. unbranded calpol) from hospital they base the dosage on weight rather than age which makes sense. I'd have thought that even in the mid weight range of the upper age range, you could compromise at a point between the two dosages.

Zirtek will not work as well as piriton as piriton is a sedating anti - histamine whereas Zirtek isn't (it is the sedating effect that calms down the itching )

That's what I was thinking, myother, but Google hasn't helped with weight based doses. Haven't been to the doctor but the pharmacist recommend zirtek. If DD has another bad night I'll go back tomorrow and ask about piriton instead. I have a friend in paediatric medicine, so if I can get her I'll ask.

My (2010) BNF gives dose for age 2-6 as 5mg/day. If she is twice the weight she was at age 2......

We've always been told age is irrelevant and to go by weight.

Starship give max single dose as 0.5mg/kg. Also if nights the bad time give it all in the evening rather than in two doses.

f1 and pixie are right: Piriton (generic name chlorpheniramine) could be "better" as it does cause more drowsiness (and a drier mouth). Oncologist suggested it for dw (cannot sleep, hot flushes as side effect of long term drugs for breast problems) but local pharmacy very "helpfully" gave her cetirizine as a "better" alternative otc drug. Made no difference at all to her night's sleep. But I had some (well out of date) chlorpheniramine and when it gets too much she takes that, sleeps well but is aware she is a bit slow the next day so used only when desperate to get some sleep.

Zyrtec definitely not as sedating. The adult dose is the one 10mg tablet per day and I take four of those - no sleepiness!

Just phoned two local pharmacies. Neither carry liquid piriton as its prescription only here (not in UK). Both havevsaud I could halve a tablet for a 6 year old, but again, u can't seem to find weight guidelines. It's so annoying not to have a by weight dose, as dratsea says, she's at least twice the weight she was when she was 2, but it's the same bloody dose...

(Did I forget to mention she had a really bad night thrashing around and crying, so I'm tired and cross)

My ds takes cetirizine 5ml X 2 everyday. He is 7 and has been completely fine. And I think he has been doing this for at least last 2 years.
He is tiny for his age.

Sorry to hear you and your daughter had a bad night. If you are desperate, try the local paediatric hospital or a paediatrician and see if anyone there can help you with the doses? There must be the information out there somewhere that can help you.

I have the problem that my daughter is short and light for her age and we always go off the weight calculations to dose her with pain medication.