Phenytoin is available in Canada by prescription only.
It is rarely used in children. If used with phenobarbital , there is a possibility that the user may become dependent on the drug. How to Use - The actual dosage will vary until the doctor stabilizes the blood levels needed for maximum therapeutic dosage. Phenytoin is taken by mouth or administered by injection in the hospital. Side Effects - Common side effects of phenytoin may include slurred speech, dizziness, insomnia, coordination problems, constipation, nausea and vomiting.