Poorly children aged one to six could previously be given up to 10ml of the products up to four times a day, reports the BBC, but new guidelines now advise lower doses for all children under four.
A spokesperson for the MHRA said the revision was not because of safety concerns about the products, but solely to ensure children were receiving the right dosage for their age.
The revised dosages are:
2-3 months - 2.5ml usually once, but a second dose permitted 4-6 hours later
3-6 months - 2.5ml - up to 4 times a day
6-24 months - 5ml - up to 4 times a day
2-4 years - 7.5ml - up to 4 times a day
4-6 years - 10ml up to 4 times a day
(Infant paracetamol suspension 120mg/5ml)