HomePharmacy Which of the following are side effects of phenytoin treatment.. Gingival hyperplasia Which of the following are side effects of phenytoin treatment? a- Acne b- Hirsuitism c- Gingival hyperplasia d- a,b,and c. Facebook Twitter Share:Which of the following are side effects of phenytoin treatment.. Gingival hyperplasia Facebook Twitter WhatsApp Pinterest LinkedIn Reddit Tumblr Telegram Email