How much motrin can i give my 12 yr old the is about 130lbs and can i break a 600mg in half?

400 mgm can be repea: It depends what you are using Motrin for.For ordinary pain like headache or musculoskeltal pain 400 mgm tablet is the ideal dose, and it can be repeated every 6 hours if needed you can break 600 mgm tablet in half but that 300 mgm may not be adequate dose for 130 lbs child, but if you have 600 mgm tab at hand you can give half tablet and see if it helps.

Use formula: The most accurate formula is 50mg per kg , or 27.7 mg per pound, divided into three or four doses per day. Do not exceed 2400 mg per day.

See below: The 10mg per kg recommendation is for children 4-11years old. Those chidren 12 years and older are included in the adult recommendations of 200-400mg every 4-6 hours. This range is maximum , not where you should start . I would start at 200 or 300 mg two to three times per day.