It was only reported for allergen extracts and was a common side effect of sublingually administrated allergen extracts
Neuropathy secondary to drugs causes a loss of sensation or movement in a part of the body due to nerve damage from taking a certain medicine, combination of medicines, or illicit (street) drugs
Less common side effects of Dilantin include overgrowth of the gums (in children and young adults during long-term therapy)
Headache, nausea, vomiting, constipation, dizziness, feeling of spinning, drowsiness, trouble sleeping, or nervousness may occur
unusual tiredness or weakness
Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat