Side Effects

Drug information provided by: Merative, Micromedex®

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Phenothiazines can sometimes cause serious unwanted effects. Tardive dyskinesia or tardive dystonia (muscle movement disorders) may occur and may not go away after you stop using the medicine. Signs of tardive dyskinesia or tardive dystonia include worm-like movements of the tongue, or other uncontrolled movements of the mouth, tongue, cheeks, jaw, body, arms, or legs. Another possible serious unwanted effect is the neuroleptic malignant syndrome (NMS). Signs and symptoms of NMS include severe muscle stiffness, fever, fast heartbeat, difficult breathing, increased sweating, and loss of bladder control. You and your doctor should discuss the good this medicine will do as well as the risks of taking it.

Stop taking this medicine and get emergency help immediately if any of the following effects occur:


  1. Confusion (severe) or coma
  2. difficult or fast breathing
  3. drooling
  4. fast heartbeat
  5. high or low (irregular) blood pressure
  6. increased sweating
  7. loss of bladder control
  8. muscle stiffness (severe)
  9. trembling or shaking
  10. trouble in speaking or swallowing

Check with your doctor immediately if any of the following side effects occur:

More common

  1. Inability to move eyes
  2. increased blinking or spasms of eyelid
  3. lip smacking or puckering
  4. muscle spasms of face, neck, body, arms, or legs causing unusual postures or unusual expressions on face
  5. puffing of cheeks
  6. rapid or worm-like movements of tongue
  7. sticking out of tongue
  8. tic-like or twitching movements
  9. trouble in breathing, speaking, or swallowing
  10. uncontrolled chewing movements
  11. uncontrolled movements of arms or legs
  12. uncontrolled twisting movements of neck, trunk, arms, or leg


  1. Irregular or slow heart rate
  2. recurrent fainting

Check with your doctor as soon as possible if any of the following side effects occur:

More common

  1. Blurred vision, change in color vision, or difficulty in seeing at night
  2. fainting
  3. loss of balance control
  4. mask-like face
  5. restlessness or need to keep moving
  6. shuffling walk
  7. stiffness of arms or legs
  8. trembling and shaking of hands and fingers

Less common

  1. Difficulty in urinating
  2. skin rash
  3. sunburn (severe)


  1. Abdominal or stomach pains
  2. aching muscles and joints
  3. agitation, bizarre dreams, excitement, or trouble in sleeping
  4. bleeding or bruising (unusual
  5. chest pain
  6. clumsiness
  7. confusion (mild)
  8. constipation (severe)
  9. convulsions (seizures)
  10. dark urine
  11. fever and chills
  12. hair loss
  13. headaches
  14. hot, dry skin or lack of sweating
  15. itchy skin (severe)
  16. muscle weakness
  17. nausea, vomiting, or diarrhea
  18. pain in joints
  19. prolonged, painful, inappropriate erection of the penis
  20. redness of hands
  21. shivering
  22. skin discoloration (tan or blue-gray)
  23. sore throat and fever
  24. sores in mouth
  25. unusual bleeding or bruising
  26. unusual tiredness or weakness
  27. yellow eyes or skin

Phenothiazines may cause your urine to be dark. In most cases, this is not a sign of a serious problem. However, if your urine does become dark, discuss it with your doctor.

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Constipation (mild)
  2. decreased sweating
  3. dizziness
  4. drowsiness
  5. dryness of mouth
  6. nasal congestion

Less common

  1. Changes in menstrual period
  2. decreased sexual ability
  3. increased sensitivity of eyes to light
  4. rough or “fuzzy” tongue
  5. secretion of milk (unusual)
  6. swelling or pain in breasts
  7. watering of mouth
  8. weight gain (unusual)

After you stop using this medicine, your body may need time to adjust. The length of time this takes depends on the amount of medicine you were using and how long you used it. During this time, check with your doctor if you notice dizziness, nausea and vomiting, stomach pain, trembling of the fingers and hands, or any of the following signs of tardive dyskinesia or tardive dystonia:

Although not all of the side effects listed above have been reported for all of the phenothiazines, they have been reported for at least one of them. However, since all of the phenothiazines are very similar, any of the above side effects may occur with any of these medicines.

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.