Mesoridazine is used to treat the symptoms of schizophrenia and reduce restlessness, anxiety, and tension. It can also reduce hyperactivity and uncooperativeness.

Mesoridazine comes as a tablet and liquid concentrate to take by mouth. It is usually taken two or three times a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take mesoridazine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

The liquid concentrate must be diluted before use. It comes with a specially marked dropper for measuring the dose. Ask your pharmacist to show you how to use the dropper if you have difficulty. To dilute the liquid concentrate, add it to at least 2 ounces (60 milliliters) of water, orange juice, or grape juice before taking it. If any of the juice gets on the dropper, rinse the dropper with tap water before replacing it in the bottle. Do not allow the liquid concentrate to touch your skin or clothing; it can irritate your skin. If you spill the liquid concentrate on your skin, wash it off immediately with soap and water.

Continue to take mesoridazine even if you feel well. Do not stop taking mesoridazine without talking to your doctor, especially if you have taken large doses for a long time. Your doctor probably will decrease your dose gradually. This drug must be taken regularly for a few weeks before its full effect is felt.

This medication should not be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking mesoridazine,

• Tell your doctor and pharmacist if you are allergic to mesoridazine or any other drugs.
• Tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially antacids, antihistamines, appetite reducers (amphetamines), benztropine (Cogentin), bromocriptine (Parlodel), carbamazepine (Tegretol), dicyclomine (Bentyl), fluoxetine (Prozac), guanethidine (Ismelin), lithium, medications for colds, medications for depression, meperidine (Demerol), methyldopa (Aldomet), phenytoin (Dilantin), propranolol (Inderal), quinidine, sedatives, trihexyphenidyl (Artane), valproic acid (Depakane), and vitamins.
• Tell your doctor if you have or have ever had depression; seizures; shock therapy; asthma; emphysema; chronic bronchitis; problems with your urinary system or prostate; glaucoma; history of alcohol abuse; thyroid problems; angina; irregular heartbeat; problems with your blood pressure; blood disorders; or blood vessel, heart, kidney, liver, or lung disease.
• Tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking mesoridazine, call your doctor.
• If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking mesoridazine.
• You should know that this drug may make you drowsy. Do not drive a car or operate machinery until you know how this drug affects you.
• Remember that alcohol can add to the drowsiness caused by this drug.
• Plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Mesoridazine may make your skin sensitive to sunlight.

Mesoridazine may cause an upset stomach. Take mesoridazine with food or milk.

Take the missed dose as soon as you remember it and take any remaining doses for that day at evenly spaced intervals. However, if you remember a missed dose when it is almost time for your next scheduled dose, skip the missed dose. Do not take a double dose to make up for a missed one.

Side effects from mesoridazine are common. Your urine may turn pink or reddish-brown; this effect is not harmful. Tell your doctor if any of these symptoms are severe or do not go away:

• Drowsiness
• Dry mouth
• Nausea
• Vomiting
• Diarrhea
• Constipation
• Restlessness
• Headache
• Weight gain

If you experience any of the following symptoms or the one listed in the IMPORTANT WARNING section, call your doctor immediately:

• Dizziness or seizures
• Lightheadedness or fainting
• Tremor
• Jaw, neck, or back muscle spasms
• Restlessness or pacing
• Fine worm-like tongue movements
• Unusual face, mouth, or jaw movements
• Shuffling walk
• Slow, jerky movements
• Seizures or convulsions
• Difficulty urinating or loss of bladder control
• Eye pain or discoloration
• Difficulty breathing or fast breathing
• Skin rash
• Yellowing of the skin or eyes

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Protect the liquid from light.

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to mesoridazine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.