More frequently reported side effects include: akathisia, blurred vision, constipation, weight gain, and xerostomia. See below for a comprehensive list of adverse effects.

Applies to haloperidol: oral solution, oral tablet

Other dosage forms:

• intramuscular oil, intramuscular solution

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

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

More common

• Difficulty with speaking or swallowing
• inability to move the 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 the arms and legs
• trembling and shaking of the fingers and hands
• twisting movements of the body
• weakness of the 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 the cheeks
• rapid or worm-like movements of the tongue
• skin rash
• uncontrolled chewing movements
• uncontrolled movements of the arms and legs

Rare

• Confusion
• convulsions (seizures)
• difficult or fast breathing
• fast heartbeat or irregular pulse
• fever (high)
• hot, dry skin, or lack of sweating
• increased blinking or spasms of the eyelid
• increased sweating
• loss of bladder control
• muscle stiffness (severe)
• muscle weakness
• sore throat and fever
• uncontrolled twisting movements of the neck, trunk, arms, or legs
• unusual bleeding or bruising
• unusual facial expressions or body positions
• unusual tiredness or weakness
• unusually pale skin
• yellow eyes or skin

Incidence not known

• Continuing nausea or vomiting
• increase in the frequency of seizures
• loss of appetite
• swelling of the face
• tiredness and weakness

Get emergency help immediately if any of the following symptoms of overdose occur while taking haloperidol:

Symptoms of overdose

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

Some side effects of haloperidol 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

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

Less common

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

Applies to haloperidol: compounding powder, injectable solution, intramuscular solution, oral concentrate, oral tablet

The most common side effects include extrapyramidal disorder, insomnia, and agitation.

Acute dystonia usually occurred early in treatment.

Sedation may occur more frequently in elderly patients.

Akathisia usually occurred within 6 hours of administration and may be indistinguishable from psychotic agitation.

Very common (10% or more): Extrapyramidal disorder (up to 34%), hyperkinesia (up to 13%), headache (up to 12%)

Common (1% to 10%): Tardive dyskinesia, dystonia, dyskinesia, akathisia, bradykinesia, hypertonia, somnolence, masked facies, tremor, dizziness, parkinsonism/parkinsonian effects

Uncommon (0.1% to 1%): Convulsion, akinesia, cogwheel rigidity, sedation, involuntary muscle contractions, gait disturbance, persistent tardive dyskinesia

Rare (0.01% to 0.1%): Motor dysfunction, neuroleptic malignant syndrome, nystagmus

Frequency not reported: Drowsiness, epileptic/grand mal seizure, vertigo, lethargy

Postmarketing reports: Opisthotonos

Very common (10% or more): Insomnia (up to 19%), agitation (up to 15%)

Common (1% to 10%): Depression, psychotic disorder

Uncommon (0.1% to 1%): Confusion, increased/decreased libido, restlessness, hallucinations

Frequency not reported: Apparent exacerbation of psychotic symptoms, anxiety, euphoria, agitation, apprehension, toxic psychosis, catatonic-like behavioral states

Common (1% to 10%): Constipation, dry mouth, salivary hypersecretion/hypersalivation, nausea, vomiting

Frequency not reported: Dyspepsia, diarrhea, heartburn, excessive salivation

Common (1% to 10%): Urinary retention, erectile dysfunction, sexual dysfunction

Uncommon (0.1% to 1%): Amenorrhea, dysmenorrhea, galactorrhea, breast discomfort/pain

Rare (0.01% to 0.1%): Menorrhagia, menstrual disorder

Frequency not reported: Priapism, oligomenorrhea, mastalgia, breast engorgement, lactation

Common (1% to 10%): Orthostatic hypotension, hypotension

Uncommon (0.1% to 1%): Tachycardia, edema

Rare (0.01% to 0.1%): QT prolongation (on ECG)

Frequency not reported: Ventricular fibrillation, Torsade de pointes/polymorphous configuration of Torsade de pointes, ventricular tachycardia, extrasystoles, peripheral edema, venous thromboembolism, deep vein thrombosis, unusual bleeding, heat stroke

Postmarketing reports: Ventricular arrhythmia, cardiac arrest, hypertension

QT prolongation, Torsade de pointes, ventricular arrhythmias/fibrillation/tachycardia and cardiac arrest occurred more frequently at high doses and/or in patients at risk for cardiovascular side effects.

Tachycardia and hypotension may occur more frequently in elderly patients. Hypotension occurred as a dose-related event.

Heat stroke included hot, dry skin, the inability to sweat, muscle weakness, and/or confusion.

Hyperammonemia occurred in a pediatric patient with citrullinemia (inherited disorder of ammonia excretion).

Common (1% to 10%): Weight increased/decreased

Frequency not reported: Hypoglycemia, hyperglycemia, loss of appetite, anorexia, hyponatremia

Postmarketing reports: Hyperammonemia

Common (1% to 10%): Oculogyric crisis, visual disturbance

Uncommon (0.1% to 1%): Blurred vision

Frequency not reported: Cataracts, retinopathy

Common (1% to 10%): Rash

Uncommon (0.1% to 1%): Photosensitivity reaction, urticaria, pruritus, hyperhidrosis

Frequency not reported: Exfoliative dermatitis, leukocytoclastic vasculitis, Toxic epidermal necrolysis, Stevens-Johnson syndrome, erythema multiforme, maculopapular/acneiform skin reactions, alopecia

Common (1% to 10%): Muscle rigidity

Uncommon (0.1% to 1%): Torticollis, muscle spasms, musculoskeletal stiffness

Rare (0.01% to 0.1%): Trismus, muscle twitching

Postmarketing reports: Rhabdomyolysis

Common (1% to 10%): Hyperthermia

Uncommon (0.1% to 1%): Unusual tiredness/weakness

Frequency not reported: Neonatal drug withdrawal syndrome, sudden/unexpected death, face edema, hypothermia

Common (1% to 10%): Abnormal liver function test

Uncommon (0.1% to 1%): Hepatitis, jaundice

Frequency not reported: Acute hepatic failure, cholestasis, impaired liver function

Common (1% to 10%): Injection site reaction

Frequency not reported: Injection site abscesses, localized erythema/swelling/tender lumps

Uncommon (0.1% to 1%): Dyspnea

Rare (0.01% to 0.1%): Bronchospasm

Frequency not reported: Laryngeal edema, laryngospasm, pulmonary embolism, increased respiratory rate/depth, sore throat, bronchopneumonia/lethal bronchopneumonia

Agranulocytosis included sore throat/fever and unusual bleeding/bruising, and typically occurred with concurrent use of other drugs.

Leukopenia and leukocytosis were usually mild and transient.

Uncommon (0.1% to 1%): Leukopenia

Frequency not reported: Agranulocytosis, neutropenia, pancytopenia, thrombocytopenia, unusual bruising, decreased red blood cell counts, anemia, lymphocytosis, monocytosis, lymphomonocytosis

Uncommon (0.1% to 1%): Hypersensitivity reactions

Frequency not reported: Anaphylactic reaction

Inappropriate antidiuretic hormone secretion occurred with hyponatremia

Rare (0.01% to 0.1%): Hyperprolactinemia

Frequency not reported: Inappropriate antidiuretic hormone secretion, gynecomastia