Be sure to reference the correct dosing based on your child's weight. Medications in children are dosed by weight, so a 50 mg dose of ibuprofen would be appropriate for a 5 kg child (10 mg/kg per dose). While a common tablet dose of ibuprofen is 200 mg, that is not universal (e.g., 800 mg) and an effective adult dose is usually a multiple of 200 mg (generally 400-800 mg). If the dosing is appropriate, though, cutting pills is a great way to get around liquid medication shortages! Unfortunately with all the kids getting sick, liquid medication shortages are getting worse by the day: Ibuprofen, acetaminophen, at least 3-4 common antibiotics, Tamiflu... (source: I'm a pediatrician, but I'm not your doctor so consult your doctor. This does not constitute medical advice, merely explanation of common dosing)