In patients receiving one of the drugs from a class of drugs known as selective serotonin reuptake inhibitors (SSRIs), for example, fluoxetine (Prozac), fluvoxamine (Luvox), paroxetine (Paxil), sertraline (Zoloft)--at the same time as monoamine oxidase inhibitor drugs (MAO inhibitors), there have been reports of serious reactions (serotonin syndrome). The serotonin syndrome may include one or more of the following: agitation, anxiety, dizziness, confusion, excessive sweating, disorientation, painful joints, vomiting, hyperexcitement, fever, loss of coordination, loss of consciousness, shivering, fast heart rate, tremor, and weakness. As discussed previously, sibutramine, like the SSRIs, blocks the reuptake of serotonin and may also cause the serotonin syndrome. Therefore, sibutramine should not be used with MAO inhibitors, and there should be at least a 2-week interval between stopping an MAO inhibitor and starting sibutramine. Similarly, there should be at least a 2-week interval after stopping sibutramine and starting an MAO inhibitor. Serotonin syndrome also has been reported with the use of SSRIs at the same time as medications used for migraines such as sumatriptan (Imitrex), zolmitriptan (Zomig) and dihydroergotamine (DHE), as well as dextromethorphan (found in many cough medications such as Robitussin-DM), meperidine (Demerol), pentazocine (Talwin) and fentanyl (Duragesic), or lithium (Eskalith). Therefore, these drugs should not be used with sibutramine.