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 elixir, oral syrup, oral tablet

Other dosage forms:

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

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

Rare - Symptoms of neuroleptic malignant syndrome; two or more occur together; most of these effects do not require emergency medical attention if they occur alone
  • Convulsions (seizures)
  • difficult or unusually fast breathing
  • fast heartbeat or irregular pulse
  • high fever
  • high or low (irregular) blood pressure
  • increased sweating
  • loss of bladder control
  • severe muscle stiffness
  • unusually pale skin
  • unusual tiredness or weakness

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

Incidence not known
  • Abdominal or stomach pain
  • black, tarry stools
  • bleeding gums
  • blood in urine or stools
  • bloody nose
  • blurred vision
  • chest pain or discomfort
  • chills
  • clay-colored stools
  • confusion as to time, place, or person
  • cough or hoarseness
  • dark urine
  • decreased awareness or responsiveness
  • difficulty or troubled breathing
  • double vision
  • fast, pounding, or irregular heartbeat or pulse
  • fever with or without chills
  • fixed position of eye
  • headache
  • heavier menstrual periods
  • high fever
  • holding false beliefs that cannot be changed by fact
  • hyperexcitability
  • increased or decreased blood pressure
  • increased sweating
  • irregular, fast or slow, or shallow breathing
  • itching
  • large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • lightheadedness, dizziness, or fainting
  • loss of appetite
  • loss of bladder control
  • lower back or side pain
  • mimicry of speech or movements
  • mutism
  • nasal stuffiness
  • nausea
  • negativism
  • nightmares
  • noisy breathing
  • not breathing
  • painful or difficult urination
  • pale or blue lips, fingernails, or skin
  • peculiar postures or movements, mannerisms or grimacing
  • pinpoint red spots on skin
  • seeing double
  • seeing, hearing, or feeling things that are not there
  • seizures
  • severe muscle stiffness
  • severe sleepiness
  • shortness of breath
  • skin rash
  • slow or irregular heartbeat
  • sore throat
  • sores, ulcers, or white spots on lips or in mouth
  • sticking out of tongue
  • swollen glands
  • tightness in chest
  • tremors
  • uncontrolled twisting movements of neck
  • unpleasant breath odor
  • unusual bleeding or bruising
  • unusual excitement, nervousness, or restlessness
  • unusual tiredness or weakness
  • vomiting of blood
  • wheezing
  • yellow eyes or skin
Symptoms of overdose
  • Discouragement
  • dizziness, faintness, or lightheadedness when getting up from a lying or sitting position suddenly
  • dry mouth
  • excessive muscle tone
  • feeling of warmth
  • feeling sad or empty
  • irritability
  • lack of appetite
  • loss of interest or pleasure
  • muscle tension or tightness
  • overactive reflexes
  • pupils of eyes large and not moving or responding to light
  • redness of the face, neck, arms and occasionally, upper chest
  • shakiness and unsteady walk
  • sudden death
  • trouble concentrating
  • trouble sleeping
  • unconsciousness
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • unusual paleness

Some side effects of promethazine 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:

Incidence not known
  • blistering, crusting, irritation, itching, or reddening of skin
  • continuing ringing or buzzing or other unexplained noise in ears
  • cracked, dry, scaly skin
  • dizziness
  • drowsiness
  • excitation
  • false or unusual sense of well-being
  • hearing loss
  • hives or welts
  • increased sensitivity of skin to sunlight
  • lack of coordination
  • loss of strength or energy
  • muscle pain or weakness
  • redness or other discoloration of skin
  • relaxed and calm
  • sunburn
  • swelling
  • unable to sleep
  • vomiting

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.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

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