Isotretinoin 40 mg, commonly known as Accutane, is a powerful medication used to treat severe acne. However, certain individuals should avoid using it due to its potential side effects and risks. Pregnant women or those planning to become pregnant must avoid isotretinoin, as it is highly teratogenic and can cause severe birth defects. Individuals with liver disease, high cholesterol, or a history of mental health issues, such as depression or suicidal thoughts, should also avoid it, as isotretinoin can exacerbate these conditions. Additionally, people who are allergic to vitamin A or have certain pre-existing eye conditions should not use isotretinoin. Regular monitoring by a healthcare provider is crucial during treatment to manage potential side effects and ensure safety. Always consult with a healthcare provider to determine if isotretinoin is appropriate for your situation and to discuss any potential risks.