Drug Interactions between metyrosine and Phenergan with Dextromethorphan

Using dextromethorphan together with metyroSINE may increase side effects such as dizziness, drowsiness, confusion, and difficulty concentrating. Some people, especially the elderly, may also experience impairment in thinking, judgment, and motor coordination. You should avoid or limit the use of alcohol while being treated with these medications. Also avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medications affect you. Talk to your doctor if you have any questions or concerns. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Using dextromethorphan together with promethazine may increase side effects such as dizziness, drowsiness, confusion, and difficulty concentrating. Some people, especially the elderly, may also experience impairment in thinking, judgment, and motor coordination. You should avoid or limit the use of alcohol while being treated with these medications. Also avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medications affect you. Talk to your doctor if you have any questions or concerns. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Treatment with promethazine can cause Parkinson-like symptoms and abnormal muscle movements, and combining it with metyroSINE may increase that risk. The most serious of the movement disorders associated with the use of these medications is a condition known as tardive dyskinesia (TD). TD mostly involves muscles in the face, but may also involve those in the limbs. You cannot control these movements, and they may not go away even after stopping the medications. There is no treatment for TD, but symptoms may lessen or disappear over time after stopping the medications. You may be more likely to develop TD if you are elderly, especially if you are a woman, or if you have diabetes. Your risk also increases the longer you take these medications and the more of each you take. Let your doctor know promptly if you experience difficulty swallowing, muscle spasm, or movements that you can't stop or control, such as lip smacking, chewing, puckering, frowning or scowling, tongue thrusting, teeth clenching, jaw twitching, blinking, eye rolling, shaking or jerking of arms and legs, tremor, jitteriness, restlessness, pacing, and foot tapping. Since these medications can also cause drowsiness, you should avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medications affect you. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.