Maxalon is contrindicated in children under 16 as it can cause a kind of seizure, so if you ask for that it will be refused. Morphine can make people drowsy and it can make peoples respiration rate slow down and in the case of an overdose it can stop breathing. Morphine given to a child will be monitored fairly carefully. they will often give small doses more regularly to make sure they don't give to much. If there is still pain you cannot overdose because the pain receptors will tae up the morphine and therefore none will be left over to be floating in the blood and effecting other receptors as the pain receptors will get priority if that makes sense.

It is true that morphine can slow down the gut so you can get more constipation, drinking enough water will help, however like Kim said having one dose won't do that.

I don't know what a LO is btw... can you enlighten me?