Side Effects of This Medicine

Along with its needed effects, haloperidol can sometimes cause serious side effects. Tardive dyskinesia (a movement disorder) may occur and may not go away after you stop using the medicine. Signs of tardive dyskinesia include fine, worm-like movements of the tongue, or other uncontrolled movements of the mouth, tongue, cheeks, jaw, or arms and legs. Other serious but rare side effects may also occur. These include severe muscle stiffness, fever, unusual tiredness or weakness, fast heartbeat, difficult breathing, increased sweating, loss of bladder control, and seizures (neuroleptic malignant syndrome). You and your doctor should discuss the good this medicine will do as well as the risks of taking it .

Stop taking haloperidol and get emergency help immediately if any of the following side effects occur:

Rare

Convulsions (seizures); difficult or fast breathing; fast heartbeat or irregular pulse; fever (high); high or low blood pressure; increased sweating; loss of bladder control; muscle stiffness (severe); unusually pale skin; unusual tiredness or weakness

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

More common

Difficulty in speaking or swallowing; inability to move eyes; loss of balance control; mask-like face; muscle spasms, especially of the neck and back; restlessness or need to keep moving (severe); shuffling walk; stiffness of arms and legs; trembling and shaking of fingers and hands; twisting movements of body; weakness of arms and legs

Less common

Decreased thirst; difficulty in urination; dizziness, lightheadedness, or fainting; hallucinations (seeing or hearing things that are not there); lip smacking or puckering; puffing of cheeks; rapid or worm-like movements of tongue; skin rash; uncontrolled chewing movements; uncontrolled movements of arms and legs

Rare

Confusion; hot, dry skin, or lack of sweating; increased blinking or spasms of eyelid; muscle weakness; sore throat and fever; uncontrolled twisting movements of neck, trunk, arms, or legs; unusual bleeding or bruising; unusual facial expressions or body positions; yellow eyes or skin

Symptoms of overdose

Difficulty in breathing (severe); dizziness (severe); drowsiness (severe); muscle trembling, jerking, stiffness, or uncontrolled movements (severe); unusual tiredness or weakness (severe)

Other 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. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Blurred vision; changes in menstrual period; constipation; dryness of mouth; swelling or pain in breasts (in females); unusual secretion of milk; weight gain

Less common

Decreased sexual ability; drowsiness; increased sensitivity of skin to sun (skin rash, itching, redness or other discoloration of skin, or severe sunburn); nausea or vomiting

Some side effects, such as trembling of fingers and hands, or uncontrolled movements of the mouth, tongue, and jaw, may occur after you have stopped taking this medicine. If you notice any of these effects, check with your doctor as soon as possible.

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