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PreSun description. Sunscreen agents are used to prevent sunburn. Limiting your exposure to the sun and using sunscreen agents when in the sun may help prevent early wrinkling and skin cancer. There are two kinds of sunscreen agents: chemical and physical. Chemical sunscreen agents protect you from the sun by absorbing the ultraviolet (UV) and visible sun rays, while physical sunscreen agents reflect, scatter, absorb, or block these rays. Sunscreen agents often contain more than one ingredient. For example, products may contain one ingredient that provides protection against the ultraviolet A (UVA) sun rays and another ingredient that protects you from the ultraviolet B (UVB) sun rays, which are more likely to cause sunburn than the UVA sun rays. Ideally, coverage should include protection against both UVA and UVB sun rays. The sun protection factor (SPF) that you find on the label of these products tells you the minimum amount of UVB sunlight that is needed with that product to produce redness on sunscreen-protected skin as compared with unprotected skin. Sunscreen products with high SPFs will provide more protection against the sun.
Why prescribed PreSun. Sunscreens help to prevent sunburn and reduce the harmful effects of the sun such as premature skin aging and skin cancer. How used PreSun. Sunscreens come in cream, lotion, gel, stick, spray, and lip balm. They are for external use only; do not swallow them. Sunscreens should be applied between 30 minutes and 2 hours before sun exposure. In general, they should be reapplied after every 80 minutes spent in the water or perspiring heavily or every 2 hours spent out of the water. Follow the directions on the label carefully, and ask your pharmacist to explain any part you do not understand. Ask your pharmacist or doctor about which sunscreen product to use. The choice depends on your sunburn and tanning history, skin type, use of other medications, and reasons for using a sunscreen. You want a product with the appropriate sun protection factor (SPF) for you. In most cases, an SPF of greater than 30 is not necessary and is not recommended. If you are using a sunscreen to prevent drug-induced photosensitivity reactions or to prevent ultraviolet-induced disorders, choose a broad-spectrum product. Ask your pharmacist for advice. If you will be swimming or sweating heavily, choose a sunscreen that is labeled waterproof or very water resistant. Talk to your doctor before using a sunscreen on an infant less than 6 months old. Use a sunscreen with a high SPF (e.g., 30) in children older than 6 months. Sunscreens should be applied liberally to all exposed areas. The average adult in a bathing suit should apply 9 half-teaspoon size portions as follows: Face and neck: 1 half-teaspoon portion Arms and shoulders: 1 half-teaspoon portion to each arm Torso: 1 half-teaspoon portion each to front and back Legs and top of feet: 2 half-teaspoon portions to each leg |