Promethazine Side Effects

Some side effects of promethazine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to promethazine: oral syrup, oral tablet

Get emergency medical help if you have any of these signs of an allergic reaction while taking promethazine: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using promethazine and call your doctor at once if you have any of these serious side effects:

• twitching, or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs;

• tremor (uncontrolled shaking), drooling, trouble swallowing, problems with balance or walking;

• feeling restless, jittery, or agitated;

• high fever, stiff muscles, confusion, sweating, fast or uneven heartbeats, rapid breathing;

• feeling like you might pass out;

• seizure (convulsions);

• pale skin, easy bruising or bleeding, fever, sore throat, flu symptoms;

• decreased night vision, tunnel vision, watery eyes, increased sensitivity to light;

• hallucinations, agitation;

• nausea and stomach pain, skin rash, and jaundice (yellowing of the skin or eyes);

• urinating less than usual or not at all;

• joint pain or swelling with fever, swollen glands, muscle aches, chest pain, vomiting, unusual thoughts or behavior, and patchy skin color; or

• slow heart rate, weak pulse, fainting, slow breathing (breathing may stop).

Less serious side effects of promethazine may include:

• dizziness, drowsiness, anxiety;

• blurred vision, dry mouth, stuffy nose;

• ringing in your ears;

• weight gain, swelling in your hands or feet;

• impotence, trouble having an orgasm; or

• constipation.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

For Healthcare Professionals

Applies to promethazine: compounding powder, injectable solution, oral syrup, oral tablet, rectal suppository

Nervous system

Nervous system side effects have been reported the most frequently. These have included excessive sedation, drowsiness, fatigue, paradoxical excitation, confusion, disorientation, tremors, convulsive seizures, and decreased motor coordination. Extrapyramidal effects (including oculogyric crises, torticollis and tongue protrusion), encephalitic symptoms, convulsions, and psychosis have been rarely reported.

Other

Neuroleptic malignant syndrome has been rarely observed during treatment with promethazine. It usually occurs within the first 30 days after exposure to neuroleptics.

Fever, altered consciousness, labile blood pressure, autonomic dysfunction, and muscle rigidity are the hallmarks of the neuroleptic malignant syndrome. The neuroleptic malignant syndrome is associated with a case fatality rate ranging from 5% to 20%. Immediate discontinuation of promethazine and intensive monitoring and supportive care are indicated.

Local

Local side effects have been associated with the inadvertent intraarterial injection of promethazine which carries a high risk of distal necrosis and frequently requires amputation of the affected limb. Subcutaneous injection has more rarely caused chemical irritation and necrosis.

Respiratory

Respiratory side effects have rarely included respiratory depression and arrest, especially with parenteral administration of promethazine. Equipment for resuscitation should be available when parenteral promethazine is used. Asthma and nasal stuffiness have also been reported.

Gastrointestinal

Gastrointestinal side effects have included nausea, vomiting, and dry mouth.

Hypersensitivity

Hypersensitivity side effects have included rare reports of rash, pruritus, hypotension, photosensitivity, and tachycardia.

Hematologic

Hematologic side effects have included rare cases of neutropenia. Leukopenia, thrombocytopenia, thrombocytopenic purpura, and agranulocytosis have also been reported.

Cardiovascular

Cardiovascular side effects have rarely included tachycardia, bradycardia, and increased or decreased blood pressure. Prolongation of the QT interval, heart block, and malignant arrhythmias have been reported in association with other phenothiazines.

Immunologic

Immunologic side effects have included rare reports of a systemic lupus erythematosus syndrome.

Hepatic

Hepatic side effects have included jaundice.

Dermatologic

Dermatologic side effects have included dermatitis, photosensitivity, and urticaria.

Psychiatric

Psychiatric side effects have included hallucinations. Other paradoxical reactions following a single dose have included nightmares, delirium and agitated behavior.

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