Dr said get regular dayquil or mucinex for my 10 1/2 year old. he is 5 foot 6 and 136 pounds is it safe to give him one that the active ingredients in each 20 ml are: dextromethorphan 20mg and guaifenesin 400mg? if it is ok is 20ml the right dose?

In children under 12, adult medications should be used with caution. If your son is experiencing severe cough, start the medication at 15ml and watch carefully for side effects. Medications should not be used for more than 3-5 days. Make sure he is drinking lots of fluids to help thin the mucus, and give him additional electrolytes such as gatorade daily.