Some common side effects of Sectral 200mg include: Lightheadedness, Nausea, Stomach upset, Dizziness, Tiredness, Trouble sleeping This medication may not allow blood to reach your hands and feet, so make sure to dress warmly. Tobacco may worsen this effect so dress warmly. Keep in mind that your doctor has prescribed you this medication because its benefits to you are greater than the risk of side effects. Many people who use this medication do not have serious side effects. However, if you undergo any serious side effects as mentioned below, then notify your doctor immediately. Symptoms of asthma, Fainting, Swelling of ankles and feet, Unusual tiredness A very serious allergic reaction to this drug is very rare, however, if you start seeing any symptoms of an allergic reaction such as trouble breathing, rash or swelling; visit your doctor immediately.