Altreno is FDA-approved. Hydrating elements such as glycerin help moisturize the skin while tretinoin can boost collagen production. Together, the ingredients fight acne to improve overall skin texture. What should I avoid while using Altreno? You should avoid sunlamps, tanning beds, and ultraviolet light during treatment with Altreno. Minimize exposure to sunlight. If you have to be in the sunlight or are sensitive to sunlight, use a sunscreen with an SPF of 15 or more and wear protective clothing and a wide-brimmed hat to cover the treated areas. What are the possible side effects of Altreno? Altreno may cause serious side effects, including: Skin Irritation: Altreno may cause irritation, including skin dryness, pain, redness, excessive flaking or peeling. If you develop these symptoms, your healthcare provider may tell you to stop using Altreno for a while, decrease how often you use it, or stop it altogether. Avoid applying Altreno to skin that is affected by eczema or sunburned. These are not all the possible side effects of Altreno. Call your healthcare provider for medical advice about side effects. You are encouraged to report negative side effects of prescription drugs. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.