Semanfinil 200 Tablet is used in the treatment of excessive daytime sleepiness (narcolepsy). It improves wakefulness and helps you to stay awake and reduces the tendency to fall asleep during the day, thus restoring the normal sleep cycle. Semanfinil 200 Tablet may be taken with or without food. It is advised to take this medicine at a fixed time each day to maintain a consistent level in the blood. If you miss any doses, take it as soon as you remember. Do not skip any doses and finish the full course of treatment even if you feel better. This medication mustn't be stopped suddenly as it may worsen your symptoms. Some common side effects of this medicine include headache, nausea, nervousness, anxiety, and insomnia (difficulty sleeping). You may also have diarrhea, indigestion, back pain, and a runny nose. However, these side effects are temporary and usually resolve on their own in some time. Please consult your doctor if these do not subside or bother you. This medicine causes dizziness and sleepiness, so do not drive or do anything that requires mental focus until you know how this medicine affects you. Always remember that this medicine only used when advised by a doctor as it is not a replacement for a good sleep routine. You should try to get the right amount of sleep every night. Before taking Semanfinil 200 Tablet, inform your doctor if you have any problems with your kidneys, heart, liver, or have a history of seizures (epilepsy or fits). Inform your doctor if you develop any unusual changes in mood or behavior, new or worsening depression, or if you have any suicidal thoughts.