Before taking modafinil, tell your doctor or pharmacist if you are allergic to it; or to armodafinil; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart problems (such as enlarged heart, mitral valve problem, chest pain, heart attack, irregular heartbeat), heart problems after taking stimulant drugs such as amphetamines (including chest pain, irregular heartbeat), high blood pressure, liver problems, mental/mood disorders (such as depression, mania, psychosis), personal or family history of a substance use disorder (such as overuse of or addiction to drugs/alcohol).Sleep disorders may reduce your ability to react quickly. Though modafinil helps keep you awake, you still may not be able to safely do things that require quick reactions (such as driving). This drug may also make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using modafinil. Modafinil may harm an unborn baby. Ask about reliable forms of non-hormonal birth control while using this medication and for 2 months after stopping treatment. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding.