Topical prolongation dacronin has side effects, mainly allergies, excessive numbness of the glans, and the development of drug dependence. 1. Allergic reaction: patients who are allergic to the components of the drug or allergic patients may have an allergic reaction when using the drug, which can be manifested as a rash at the site of the drug, itching, and in severe cases, blisters, vesicles, or worse, anaphylactic shock. 2. Excessive numbness of the glans: Dacronin is a local anesthetic, external use can penetrate the skin, anesthetize the subcutaneous nerves, block sensory conduction, the treatment of premature ejaculation, if the dosage is too much, it may lead to excessive numbness of the glans, the lack of sexual pleasure, ejaculation difficulties, and even erectile dysfunction. 3. Drug dependence: mainly occurs in patients who have been using medication for a long time, which creates physiological and psychological dependence on the medication, and once the medication is stopped, the symptoms of premature ejaculation may become more serious. Therefore, when using Dacronin, be sure to use the drug under the guidance of a specialist physician to avoid adverse consequences.