Pilot Trial of Supplemental Vitamin A and Nicotinamide

Exclusion Criteria

• •Liver disease;
• •Active peptic ulcer disease;
• •Recent myocardial infarction;
• •Hypotension;
• •Internal malignancy within past 5 years;
• •Renal impairment with eGFR\<15 mL/min/1.73 m2;
• •Being unable for follow up due to social reasons;
• •Gorlin's syndrome or other genetic skin cancer syndrome;
• •Huge number of current skin cancers;
• •Metastatic SCC or invasive melanoma within the past 5 years;
• •Pregnancy or lactation;
• •Need for ongoing carbamazepine use (which could have a possible interaction with NAM);
• •Use of acitretin or other oral retinoids within the past 6 months;
• •Use of supplemental NAM, niacin, vitamin A, or beta carotene within the past 6 months;
• •Field treatment for actinic keratoses (AKs) within the previous 4 weeks;
• •Use of topical steroids.