Most of the patients who use this medication do not experience any serious side effects. Some side effects that are not too serious unless they persist or get worse include dizziness, rapid heartbeat, face flushing, low blood pressure, drowsiness, or headaches. There is one serious reaction than can occur but it is very rare. It will usually occur right after taking the very first dosage of the medication. If you feel any inability to move your arms or legs, are shaky, have extreme weakness or pain in the joints, vision changes or unexplained mood swings contact your physician immediately.