Isotretinoin has been used to treat acne for more than 30 years now. It is listed in both domestic and international acne guidelines as a first-line treatment selective drug for moderate to severe acne. However, the drug does have many adverse effects, i.e. side effects, which make many patients very reluctant to accept it. Given that isotretinoin is the only effective drug that affects the 4 components of acne pathogenesis (follicular opening keratinization, sebum secretion, bacterial colonization, and inflammatory response), it has become an important drug of choice for the treatment of acne. It is important to understand and take care of how to prevent these side effects from occurring. 1. Patients with recent fertility needs must avoid taking isotretinoin. Teratogenicity is the most serious consequence and the most certain reaction among the adverse effects of this drug. It can lead to serious malformations in the fetus such as craniofacial defects, cleft lip, earlessness, narrowing of the ear canal, small eye deformities, hydrocephalus, short limb defects, etc. After birth, even infants without anatomical defects may develop neuropsychological dysfunction or developmental delays later in life development. Therefore, according to the process of drug metabolism, female patients of childbearing age should use strict contraception one month before, during and three months after the end of treatment. If you have a need for fertility, be sure to communicate with your doctor in a timely manner. If an unwanted pregnancy occurs during the course of treatment, it must be aborted. Isotretinoin does not affect fertility, nor does it affect male sperm. 2, correctly treat the occurrence and treatment of lip inflammation after oral administration Oral isotretinoin in which lip inflammation occurs in 98% of treated patients and is also a sign that the drug is taking effect. If there is no obvious dryness of the mouth and lips, the treatment effect is also poor, but it is possible that labyrinthitis occurs in the front and the onset of effect occurs after. In this case, it must be correctly recognized and reasonably treated. The occurrence of dry mouth and lips requires protection such as lip balm, and drinking more water will not solve the problem. Once a reaction such as chapped lips occurs, the dosage should be reduced or even discontinued, and do not tear off the skin lesions to avoid aggravating the lip and mouth reaction. The way to reduce the dose can be reasonably adjusted according to the degree of labyrinthitis, usually taken every 2 days, or every month for a week, the method of taking 20mg per day can be effective prevention. 3. Response to elevated blood after oral administration Elevated blood lipids can occur in some patients, but are usually transient, usually appearing in the first to second month of treatment, and can be restored by stopping drug treatment for 2 to 4 weeks. Acne occurs mostly in young people, who are very capable of metabolizing lipids and usually do not have much of a problem. However, those with obesity, hyperinsulinemia, apoE gene and family history of hypertriglyceridemia, family history of diabetes and alcohol addiction are at higher risk and should be carefully avoided. Therefore avoiding a high-fat diet while taking the drug and also abstaining from alcohol is a must. It is usually not necessary to routinely check blood lipids. 4, the correct evaluation of liver damage A few people will experience liver damage during the drug, but most of them are mildly elevated aminotransferases, which usually occurs within the first month of taking the drug, and can return to normal if you continue to take the drug, but of course it can be restored when you stop taking the drug, which usually does not affect the treatment. Usually there is no need to check liver function before and after taking the medication, unless there is obvious discomfort in the liver area, yellow urine, poor appetite and so on. However, people who have a history of hepatitis B or who have been drinking alcohol for a long time should avoid taking the medication as much as possible. It is necessary to abstain from alcohol while taking the drug, and not to take other drugs that damage the liver, so as not to induce or aggravate liver damage. 5. Regarding the age of taking the drug Animal experimental studies suggest that the drug can affect the bones, but there is no clinical evidence. For the sake of insurance, the drug is not recommended for patients under 12 years of age. Of course, the use of stronger medications for acne is also less advocated in patients under 12 years of age. 6. Other possible precautions The drug has a certain degree of photosensitivity. Avoid sun exposure while taking the drug to avoid phototoxic reactions. However, it is possible to receive red and blue light treatment while taking the medication, and in principle there is not much risk. Patients who wear contact lenses should promptly inform their physicians that it is inappropriate to take such medication. Patients who have dry syndrome should try not to take isotretinoin as it may aggravate dry syndrome. The side effects of taking the drug are more closely related to the daily dose and less related to the course of treatment, which needs to be ensured for a sufficient duration if it can effectively prevent recurrence.