The usage and dosage of tretinoin should be adjusted according to the indications and individual patient conditions, and special attention should be paid to safety when using it for special populations. The following provides detailed instructions on usage, dosage, and medication for special populations.

1. Usage and dosage

(1) Acne treatment

Recommended to use once a night, clean dry skin and apply thinly to the affected area. Initial use can start every other day and gradually increase to once a day to establish tolerance.

(2) Skin photoaging

It is recommended to use it in the evening, starting 2-3 times a week, gradually increasing the frequency according to skin tolerance. Thoroughly clean and dry the skin before use.

(3) Precautions for use

Avoid contact with mucous membranes such as eyes, mouth, and nose. After use, wait for 15-20 minutes before applying other skincare products. Mild irritation may occur during the initial stage of treatment, usually adapting after 2-4 weeks.

2. Medication for special populations

(1) Pregnant women

Retinoic acid has teratogenic risks and is contraindicated for pregnant women. Women of childbearing age should take reliable contraceptive measures during use, and it is recommended to undergo pregnancy testing before treatment.

(2) Lactating women

It is not yet clear whether the medication is secreted into breast milk. For safety reasons, it is recommended to suspend or stop breastfeeding during lactation.

(3) Children

The safety of children under 12 years old has not been established and is not recommended for use. Teenagers should use it under the guidance of a doctor.

(4) Elderly people

Elderly patients have sensitive skin, it is recommended to start using at lower frequencies and closely monitor skin reactions.

(5) Liver and kidney dysfunction

There is currently no clear dosage adjustment recommendation, but due to the fact that the drug is metabolized by the liver, patients with severe liver dysfunction should use it with caution.