This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Most common side effect of phenytoin is: 
Select and explain. 
A. Gingival hyperplasia, B. Dental stains, C. Hypertension, D. Gingival necrosis
A: Gingival hyperplasia
Answer: A: Gingival hyperplasia 
Explanation: Side Eﬀect Of Phenytoin 

Headache
Nausea
Vomiting 
Constipation 
Dizziness
Feeling of spinning 
Drowsiness
Swelling and bleeding of the gums
Trouble in sleeping or nervousness may occur