Acid a vit (其他名字 Retin A 0,025)

Drug Name

Retin-A (Tretinoin) 

Drug Uses

Retin-A is often used to improve the appearance and texture of the skin. It produces a mild, superficial peel of the epidermis. Retin-A has effects on the both the superficial (epidermis) and the deep (dermis) parts of the skin. The major benefit is to decrease the effects of sunlight caused aging by increasing the speed with which the surface cells are replaced. 

How to use

Apply a thin layer to affected area once a day at bedtime. Use a gauze pad or cotton swab to apply the liquid. Wash your hands immediately after use. Using this medication more frequently or in excessive amounts does not improve the results, but may increase side effects. Avoid applying near the eyes, mouth, or open cuts since this medication can irritate sensitive skin. Acne may appear to worsen when the medication is first used; continue therapy. It may take three to six weeks before the full benefits of this medication are seen. Use mild soap when washing your face. Do not wash face excessively. Abrasive soaps, cleansers, medicated creams or lotions can increase skin irritation. Consult your doctor or pharmacist about their use. Use other acne preparations with caution while using this medication.

Drug Class and Mechanism

Tretinoin is a derivative of vitamin A. Topical Tretinoin is used in the treatment of mild to moderate acne and on skin that has been damaged by excessive exposure to the sun. Tretinoin irritates the skin and causes the cells of the skin to grow (divide) and die more rapidly, that is, it increases the turnover of cells. The number of layers of cells in the skin actually is reduced. In patients with acne, new cells replace the cells of existing pimples, and the rapid turnover of cells prevents new pimples from forming. By a similar mechanism, Tretinoin can reduce some wrinkles, areas of darkened skin, and rough areas of skin, all of which occur in sun-damaged skin. In patients with sun-damaged skin, improvements in the skin usually are seen within the first 3 to 4 weeks of treatment. Brown spots begin to fade after six to eight weeks. Wrinkles decrease or disappear after three to six months. Following application to the skin, a minimal amount of drug is absorbed into the body.

Missed Dose

If you miss a dose, use it as soon as remembered; do not use if it is almost time for the next dose, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.

Storage

Store at room temperature away from sunlight. Keep this and all medications out of the reach of children.

SAFETY INFORMATION

Warnings/Precautions

This medication can increase sensitivity to sunlight, wind and cold. Avoid prolonged exposure to the sun and sunlamps. Wear protective clothing and use an effective sunscreen. This medication should be used during pregnancy only if clearly needed. It is not known if Retin-A appears in breast milk. Consult your doctor before breast-feeding.

SIDE EFFECTS

Possible Side Effects

Due to the possibility of irritation, it is advisable to begin treatment on a small area of skin. Exposure to the sun or to ultraviolet rays causes additional irritation. During treatment, such exposure should be avoided as much as possible or a sun block should be used. During the first weeks of treatment there may be an apparent worsening of the problem. Such a reaction is perfectly normal because small cysts deep within the skin are being eliminated at an accelerated rate. This medication can increase sensitivity wind and cold. Avoid prolonged exposure to the sun and sunlamps. Wear protective clothing and use an effective sunscreen. If any ingredient should cause hypersensitivity, discontinue use.

More Information

Serious side effects are not likely to occur. Stop using tretinoin topical and seek emergency medical attention if you experience an allergic reaction (shortness of breath; closing of your throat; swelling of your lips, face, or tongue; or hives). 
You may experience some burning, warmth, stinging, tingling, itching, redness, swelling, dryness, peeling, or irritation while you are using tretinoin topical. If these side effects are excessive, talk to your doctor. You may need a lower dose or less frequent applications of tretinoin topical.
If you notice a change in your skin color, contact your doctor.
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.