Common side effects when used by mouth include shortness of breath, headache, numbness, depression, skin dryness, itchiness, hair loss, vomiting, muscle pains, and vision changes. Other severe side effects include high white blood cell counts and blood clots. When used as a cream side effects include skin redness, peeling, and sun sensitivity. Use during pregnancy is known to harm the baby. It is in the retinoid family of medications. Tretinoin was patented in 1957 and approved for medical use in 1962.