Phenergan Side Effects

Generic name: promethazine

Medically reviewed by Drugs.com. Last updated on May 8, 2024.

Note: This document provides detailed information about Phenergan Side Effects associated with promethazine. Some dosage forms listed on this page may not apply specifically to the brand name Phenergan.

Applies to promethazine: solution.

Other dosage forms:

• oral syrup, oral tablet
• rectal suppository

Important warnings This medicine can cause some serious health issues

Injection route (solution)

Respiratory Depression – Pediatrics. Promethazine hydrochloride injection should not be used in pediatric patients less than 2 years of age because of the potential for fatal respiratory depression.

Postmarketing cases of respiratory depression, including fatalities, have been reported with use of promethazine in pediatric patients less than 2 years of age.

Caution should be exercised when administering promethazine hydrochloride injection to pediatric patients 2 years of age and older.Severe Tissue Injury, Including Gangrene. Promethazine hydrochloride injection can cause severe chemical irritation and damage to tissues regardless of the route of administration.

Irritation and damage can result from perivascular extravasation, unintentional intra-arterial injection, and intraneuronal or perineuronal infiltration.

Adverse reactions include burning, pain, thrombophlebitis, tissue necrosis, and gangrene.

In some cases , surgical intervention, including fasciotomy, skin graft, and/or amputation have been required.Due to the risks of intravenous injection, the preferred route of administration of promethazine hydrochloride injection is deep intramuscular injection.

Subcutaneous injection is contraindicated.

Serious side effects of Phenergan

Along with its needed effects, promethazine (the active ingredient contained in Phenergan) 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 or nurse immediately if any of the following side effects occur while taking promethazine:

Rare side effects

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

Incidence not known

• abdominal or stomach pain
• black, tarry stools
• blood in the urine
• bloody nose
• blurred vision
• chest pain or discomfort
• chills
• clay-colored stools
• cough or hoarseness
• dark urine
• decreased awareness or responsiveness
• difficulty with speaking
• dizziness
• double vision
• drooling
• fast, pounding, or irregular heartbeat or pulse
• fever with or without chills
• fixed position of the eye
• headache
• heavier menstrual periods
• increases and decreases in blood pressure
• itching
• large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
• lightheadedness, dizziness, or fainting
• loss of appetite
• loss of balance control
• lower back or side pain
• mimicry of speech or movements
• muscle trembling, jerking, or stiffness
• mutism
• nausea
• negativism
• noisy breathing
• painful or difficult urination
• peculiar postures or movements, mannerisms, or grimacing
• pinpoint red spots on the skin
• restlessness
• seeing double
• seeing, hearing, or feeling things that are not there
• seizures
• severe sleepiness
• shortness of breath
• shuffling walk
• skin rash
• slow or irregular heartbeat
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• stiffness of the limbs
• swollen glands
• tenderness, pain, swelling, warmth, skin discoloration, and prominent superficial veins over the affected area
• tightness in the chest
• tremors
• twisting movements of the body
• uncontrolled movements, especially of the face, neck, and back
• unpleasant breath odor
• unusual bleeding or bruising
• vomiting of blood
• wheezing
• yellow eyes or skin

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

Symptom of overdose

• abnormal movements
• confusion as to time, place, or person
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• feeling of warmth
• holding false beliefs that cannot be changed by fact
• hyperexcitability
• irregular, fast or slow, or shallow breathing
• nightmares
• pale or blue lips, fingernails, or skin
• pupils of the eyes, large and not moving or responding to light
• redness of the face, neck, arms, and occasionally, upper chest
• sweating
• troubled breathing
• unusual excitement, nervousness, or restlessness

Other side effects of Phenergan

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, or reddening of the skin
• continuing ringing or buzzing or other unexplained noise in the ears
• discoloration of the skin
• drowsiness
• dry mouth
• excitation
• false or unusual sense of well-being
• hearing loss
• hives or welts
• increased sensitivity of the skin to sunlight
• lack of coordination
• loss of strength or energy
• muscle pain or weakness
• nasal stuffiness
• nervousness
• severe sunburn
• sleeplessness
• trouble sleeping
• unable to sleep
• vomiting

For healthcare professionals

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

General adverse events

The most commonly reported side effect include drowsiness, dizziness, and restlessness.^[Ref]

Nervous system

• Frequency not reported: Drowsiness, sedation, somnolence, dizziness, extrapyramidal symptoms, incoordination, tremors, convulsive seizures, faintness, headache, neuroleptic malignant syndrome/fatal neuroleptic malignant syndrome, psychomotor impairment, antimuscarinic effects, abnormal movements, central nervous system depression, activation of epileptogenic foci, tardive dyskinesia, tic-like movements of the head and face^[Ref]

Local

• Frequency not reported: Severe chemical irritation, tissue damage, burning, pain, erythema, swelling, sensory loss, palsies, paralysis, severe spasm of distal vessels, thrombophlebitis, venous thrombosis, phlebitis, abscesses, tissue necrosis, gangrene^[Ref]

Psychiatric

• Frequency not reported: Restlessness, anxiety, confusion, disorientation, euphoria, nervousness, insomnia, catatonic-like states, irritability, hysteria, hallucinations, hyperexcitability, nightmares, delirium, agitation/agitated behavior^[Ref]

Gastrointestinal

• Frequency not reported: Dry mouth, nausea, vomiting, constipation, diarrhea, tongue protrusion, gastric irritation, epigastric distress^[Ref]

Cardiovascular

• Frequency not reported: Bradycardia, tachycardia, palpitations, hypotension, arrhythmias, circulatory collapse, increased or decreased blood pressure^[Ref]

Hematologic

• Frequency not reported: Leukopenia, thrombocytopenia, thrombocytopenic purpura, agranulocytosis, blood dyscrasias, hemolytic anemia, aplastic anemia^[Ref]

Dermatologic

• Frequency not reported: Dermatitis, photosensitivity, urticaria, rash, pruritus, angioneurotic edema, topical contact dermatitis^[Ref]

Other

• Frequency not reported: Lassitude, tinnitus, fatigue, tiredness, paradoxical reactions, decreased performance (impaired driving/poor work performance, incoordination, reduced motor skills, impaired information processing)^[Ref]

Respiratory

• Frequency not reported: Asthma, nasal stuffiness, respiratory depression/fatal respiratory depression, apnea/fatal apnea, marked irregular respiration^[Ref]

Ocular

• Frequency not reported: Blurred vision, oculogyric crisis, diplopia, angle closure glaucoma^[Ref]

Hypersensitivity

• Frequency not reported: Anaphylaxis, angioedema, hypersensitivity reactions^[Ref]

Musculoskeletal

• Frequency not reported: Torticollis, muscle spasms, muscle dyskinesia^[Ref]

Metabolic

• Frequency not reported: Anorexia, loss of appetite, appetite stimulation^[Ref]

Hepatic

• Frequency not reported: Jaundice, obstructive jaundice^[Ref]

Genitourinary

• Frequency not reported: Urinary retention and hesitancy^[Ref]

Frequently asked questions

• Par promethazine with codeine vs Hi-Tech promethazine with codeine?
• How long does promethazine stay in your system?

Further information

Phenergan side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer