phenergan
Phenergan (Promethazine Hydrochloride) is a phenothiazine used to treat Anaphylaxis, Allergic Conjunctivitis, Motion Sickness, Nausea.
Promethazine Hydrochloride · by Pharmobedient
Available as a generic: Promethegan
⚠ FDA reports a current shortage of the injection form — availability differs between suppliers — see drug shortages →Key facts
- Active ingredient
- Promethazine Hydrochloride
- Drug class
- Phenothiazine
- Form
- Injectable
- Strength
- Promethazine Hydrochloride 50MG **Federal Register Determination That Product was not Discontinued or Withdrawn for Safety or Effectiveness reasons**
- Type
- Prescription (Rx)
- Brand or generic
- Brand-name
- May treat
- anaphylaxis, allergic conjunctivitis, motion sickness
- Manufacturer
- Pharmobedient
- Half-life
- about 9 to 16 hours (how long it stays in your system)
- What the pharmacy pays
- ~$1.53 for 30 — not your price
- FDA application
- NDA011689
- Availability
- Discontinued (per FDA)
- FDA boxed warning
- Yes — see the boxed warning
What is Phenergan?
From the FDA label:Injection (promethazine hydrochloride injection, USP) is a sterile, pyrogen-free solution for deep intramuscular or intravenous administration. Promethazine hydrochloride (10 H -Phenothiazine-10-ethanamine, N,N,α -trimethyl-, monohydrochloride, (±)-) is a racemic compound and has the following structural formula: C 17 H 21 ClN 2 S MW 320.88 Each mL contains promethazine hydrochloride, either 25 mg or 50 mg, edetate disodium 0.1 mg, calcium chloride 0.04 mg, sodium metabisulfite 0.25 mg and phenol 5 mg in Water for Injection. pH 4.0 to 5.5; buffered with acetic acid-sodium acetate. PHENERGAN Injection is a clear, colorless solution. The product is light sensitive. It should be inspected before use and discarded if either color or particulate is observed. chemical structure
How to use
Important Administration Information for Adult and Pediatric Patients 2 Years of Age and Older The preferred route of administration of PHENERGAN Injection is by deep intramuscular administration (see WARNINGS - Severe Tissue Injury, Including Gangrene ). PHENERGAN Injection may be administered intravenously after dilution as recommended below (see Preparation and Administration ). If pain occurs at the injection site during intravenous infusion, immediately discontinue the infusion, and evaluate for possible arterial injection or perivascular extravasation. Allergic Conditions The average adult dose is 25 mg. This dose may be repeated within two hours if necessary, but continued therapy, if indicated, should be via the oral route as soon as existing circumstances permit. After initiation of treatment, dosage should be adjusted to the smallest amount adequate to relieve symptoms. The average adult dose for amelioration of allergic reactions to blood or plasma is 25 mg. Sedation In hospitalized adult patients, nighttime sedation may be achieved by a dose of 25 to 50 mg of PHENERGAN Injection. Nausea and Vomiting For control of nausea and vomiting, the usual adult dose is 12.5 to 25 mg, not to be repeated more frequently than every four hours. When used for control of postoperative nausea and vomiting, the dosage of analgesics and barbiturates should be reduced accordingly (see…
Side effects
Respiratory Depression PHENERGAN Injection is contraindicated in pediatric patients less than 2 years of age, because of the potential for fatal respiratory depression. PHENERGAN Injection should be used with caution in pediatric patients 2 years of age and older (see WARNINGS - Respiratory Depression ). Severe Tissue Injury, Including Gangrene PHENERGAN Injection has been reported to cause severe chemical irritation and damage to tissues, including gangrene, regardless of the route of parenteral administration . Intra-arterial and subcutaneous injection have resulted in more significant complications (see CONTRAINDICATIONS ). Reported adverse reactions included burning, pain, erythema, swelling, sensory loss, palsies, paralysis, severe spasm of distal vessels, thrombophlebitis, venous thrombosis, phlebitis, abscesses, tissue necrosis, and gangrene (see WARNINGS - Severe Tissue Injury, Including Gangrene ). Central Nervous System Drowsiness is the most prominent CNS effect of this drug. Sedation, somnolence, blurred vision, dizziness, confusion, disorientation, and extrapyramidal symptoms such as oculogyric crisis, torticollis, and tongue protrusion; lassitude, tinnitus, incoordination, fatigue, euphoria, nervousness, diplopia, insomnia, tremors, convulsive seizures, excitation, catatonic-like states, hysteria. Hallucinations have also been reported. Cardiovascular Increased…
FDA Boxed Warning (the FDA’s most serious warning)
Boxed (black-box) warning — from the FDA label
Respiratory Depression – Pediatrics PHENERGAN 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 PHENERGAN Injection to pediatric patients 2 years of age and older (See Warning – Respiratory Depression ) Severe Tissue Injury, Including Gangrene Severe chemical irritation and damage to tissues regardless of the route of parenteral administration has been reported in patients treated with PHENERGAN Injection including gangrene, tissue necrosis, and thrombophlebitis; and in some cases, surgical intervention including fasciotomy, skin graft, and/or amputation have been required (see WARNINGS – Severe Tissue Injury, Including Gangrene .). The use of promethazine hydrochloride injection by the following routes of administration is CONTRAINDICATED: Intravenous injection at concentrations greater than 1 mg/mL Intra-arterial injection Subcutaneous injection (see CONTRAINDICATIONS ). The preferred route of administration is by deep intramuscular administration. PHENERGAN Injection may be administered intravenously after dilution through an intravenous catheter inserted in a large vein. Preferably through a central venous catheter (see DOSAGE AND ADMINISTRATION ). If pain occurs at the injection site during intravenous infusion, immediately discontinue the infusion and evaluate for possible arterial injection or perivascular extravasation, and initiate appropriate medical management.
Warnings
Important safety information
Respiratory Depression Pediatrics PHENERGAN 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. A wide range of weight-based doses of PHENERGAN Injection have resulted in respiratory depression in these patients. Caution should be exercised when administering PHENERGAN Injection to pediatric patients 2 years of age and older. It is recommended that the lowest effective dose of PHENERGAN Injection be used in pediatric patients 2 years of age and older. Avoid concomitant administration of other drugs with respiratory depressant effects because of an association with respiratory depression, and sometimes death, in pediatric patients. Other Because of the risk of potentially fatal respiratory depression, use of PHENERGAN Injection in patients with compromised respiratory function or patients at risk for respiratory failure (e.g. COPD, sleep apnea) should be avoided. Severe Tissue Injury, Including Gangrene PHENERGAN Injection has been reported to cause severe chemical irritation and damage to tissues, including gangrene, regardless of the route of parenteral administration. Intra-arterial and subcutaneous administration have resulted in more significant complications. The use of PHENERGAN Injection by intravenous injection at concentrations greater than 1 mg/mL, intra- arterial injection, or subcutaneous injection is contraindicated (see CONTRAINDICATIONS ). Irritation and damage can result from perivascular extravasation, intra- arterial injection, and intraneuronal or perineuronal infiltration. Inadvertent intra-arterial injection can cause severe arteriospasm. Other reported adverse reactions included burning, pain, erythema, swelling, sensory loss, palsies, paralysis, severe spasm of distal vessels, thrombophlebitis, venous thrombosis, phlebitis, abscesses, tissue necrosis, and gangrene. In some cases, surgical intervention, including fasciotomy, skin graft, and/or amputation have been required. The preferred route of administration of PHENERGAN Injection is by deep intramuscular administration. PHENERGAN Injection may be administered intravenously after dilution through an intravenous catheter inserted in a large vein. Preferably through a central venous catheter (see DOSAGE AND ADMINISTRATION ). If pain occurs at the injection site during intravenous infusion, immediately discontinue the infusion, evaluate for possible arterial injection or perivascular extravasation, and initiate appropriate medical management. CNS Depression PHENERGAN Injection may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a vehicle or operating machinery. The impairment may be amplified by concomitant use of other central-nervous-system depressants such as alcohol, sedative/hypnotics (including barbiturates), general anesthetics, narcotics, narcotic analgesics, tricyclic antidepressants, and tranquilizers; therefore such agents should either be eliminated or given in reduced dosage in the presence of promethazine hydrochloride (see PRECAUTIONS - Information for Patients and Drug Interactions ). Lower Seizure Threshold PHENERGAN Injection may lower seizure threshold and should be used with caution in persons with seizure disorders or in persons who are using concomitant medications, such as narcotics or local anesthetics, which may also affect seizure threshold. Bone-Marrow Depression PHENERGAN Injection should be used with caution in patients with bone-marrow depression. Leukopenia and agranulocytosis have been reported, usually when promethazine hydrochloride has been used in association with other known marrow-toxic agents. Neuroleptic Malignant Syndrome A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with promethazine hydrochloride alone or in combination with antipsychotic drugs. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmias). The diagnostic evaluation of patients with this syndrome is complicated. In arriving at a diagnosis, it is important to identify cases where the clinical presentation includes both serious medical illness (e.g., pneumonia, systemic infection, etc.) and untreated or inadequately treated extrapyramidal signs and symptoms (EPS). Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever and primary central nervous system (CNS) pathology. The management of NMS should include 1) immediate discontinuation of promethazine hydrochloride, antipsychotic drugs, if any, and other drugs not essential to concurrent therapy, 2) intensive symptomatic treatment and medical monitoring, and 3) treatment of any concomitant serious medical problems for which specific treatments are available. There is no general agreement about specific pharmacological treatment regimens for uncomplicated NMS. Since recurrences of NMS have been reported with phenothiazines, the reintroduction of promethazine hydrochloride should be carefully considered. Sulfite Sensitivity PHENERGAN Injection contains sodium metabisulfite, a sulfite that may cause allergic-type reactions, including anaphylactic symptoms and life-threatening or less severe asthma episodes, in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people. Visual Inspection This product is light sensitive and should be inspected before use and discarded if either color or particulate is observed. Cholestatic Jaundice Administration of promethazine has been associated with reported cholestatic jaundice.
Who should not take Phenergan
The use of PHENERGAN Injection is contraindicated: In pediatric patients less than 2 years of age due to the risk of respiratory depression (see WARNINGS – Respiratory Depression ). For use as an intravenous injection at concentrations greater than 1 mg/mL due to the risk of perivascular extravasation, unintentional intra-arterial injection, and intraneuronal or perineuronal infiltration (see WARNINGS - Severe Tissue Injury, Including Gangrene and DOSAGE AND ADMINISTRATION ). For use as an intra-arterial injection due to the likelihood of severe arteriospasm and the possibility of resultant gangrene (see WARNINGS - Severe Tissue Injury, Including Gangrene ). For use as a subcutaneous injection because chemical irritation and necrotic lesions have been reported (see WARNINGS - Severe Tissue Injury, Including Gangrene ). In patients in a comatose state. In patients who have demonstrated an idiosyncratic reaction or hypersensitivity to promethazine hydrochloride or other phenothiazines.
Overdose — what happens if you take too much
Signs and symptoms of overdosage range from mild depression of the central nervous system and cardiovascular system to profound hypotension, respiratory depression, unconsciousness and sudden death. Other reported reactions include hyperreflexia, hypertonia, ataxia, athetosis, and extensor-plantar reflexes (Babinski reflex). Stimulation may be evident, especially in pediatric patients and geriatric patients. Convulsions may rarely occur. A paradoxical-type reaction has been reported in pediatric patients receiving single doses of 75 mg to 125 mg orally, characterized by hyperexcitability and nightmares. Atropine-like signs and symptoms-dry mouth; fixed, dilated pupils; flushing; etc., as well as gastrointestinal symptoms, may occur. Treatment Treatment of overdosage is essentially symptomatic and supportive. Only in cases of extreme overdosage or individual sensitivity do vital signs, including respiration, pulse, blood pressure, temperature, and EKG, need to be monitored. Attention should be given to the reestablishment of adequate respiratory exchange through provision of a patent airway and institution of assisted or controlled ventilation. Diazepam may be used to control convulsions. Acidosis and electrolyte losses should be corrected. Note that any depressant effects of PHENERGAN Injection are not reversed by naloxone. Avoid analeptics, which may cause convulsions. The…
U.S. Poison Control: call or text 1-800-222-1222 (free, 24/7). In an emergency call 911. From the FDA label; not medical advice.
Interactions
CNS Depressants PHENERGAN Injection may increase, prolong, or intensify the sedative action of central-nervous-system depressants, such as alcohol, sedative/hypnotics (including barbiturates), general anesthetics, narcotics, narcotic analgesics, tricyclic antidepressants, and tranquilizers; therefore, such agents should be avoided or administered in reduced dosage to patients receiving promethazine hydrochloride. When given concomitantly with PHENERGAN Injection, the dose of barbiturates should be reduced by at least one-half, and the dose of narcotics should be reduced by one-quarter to one-half. Dosage must be individualized. Excessive amounts of PHENERGAN Injection relative to a narcotic may lead to restlessness and motor hyperactivity in the patient with pain; these symptoms usually disappear with adequate control of the pain. Epinephrine Because of the potential for promethazine hydrochloride to reverse epinephrine’s vasopressor effect, epinephrine should NOT be used to treat hypotension associated with PHENERGAN Injection overdose. Anticholinergics Concomitant use of other agents with anticholinergic properties should be undertaken with caution. Monoamine Oxidase (MAO) Inhibitors Drug interactions, including an increased incidence of extrapyramidal effects, have been reported when some MAO Inhibitors and phenothiazines are used concomitantly. This possibility should be considered with PHENERGAN Injection.
How long does Promethazine Hydrochloride stay in your body?
The elimination half-life of promethazine hydrochloride is about 9 to 16 hours — the time it takes the body to clear about half of it. As a rule of thumb, a medicine is mostly gone after roughly 4 to 5 half-lives, though this varies from person to person with age and kidney or liver function. Kinetics are linear (no saturable/dose-dependent behavior). The FDA label reports a plasma half-life of 9-16 hours after IV dosing and a mean of 9.8 ± 3.4 hours after IM dosing; the oral tablet label omits a numeric half-life but describes the same disposition. Duration of clinical effect (about 4-6 hours, occasionally up to 12) is shorter than the elimination half-life, so sedation can wear off well before the drug clears. Promethazine is metabolized in the liver to sulfoxides of promethazine and N-desmethylpromethazine (the main urinary metabolites); the label does not characterize these as clinically active or as outlasting the parent. Not a prodrug. Because clearance is hepatic, impaired liver function may prolong the half-life; the label gives no specific age- or kidney-based half-life values.
This is general information, not medical advice. It doesn’t tell you when a drug test would read negative (tests detect substances for different, often longer, windows) or when it’s safe to take another dose — ask your pharmacist or prescriber. Source: Promethazine Hydrochloride Injection, USP — FDA label (DailyMed).
Drug class
May treat (source: NIH RxClass)
See how Phenergan ranks — best-rated phenothiazine for:
Dosage forms
Injectable
The forms currently marketed in the U.S., per the FDA National Drug Code Directory.
Ways to save
Ask for the generic
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Use copay cards
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Frequently asked questions
- What does Phenergan treat?
- Phenergan (Promethazine Hydrochloride) may be used to treat anaphylaxis, allergic conjunctivitis, motion sickness, nausea, pain, postoperative complications, based on NIH RxClass drug-classification data (conditions a drug may treat — not a verbatim copy of the FDA-approved label). This is general reference, not medical advice.
- How much does Phenergan cost?
- Nobody can tell you what you will pay — your price is set by your insurer's formulary, your deductible and the pharmacy's markup, and none of those are published. What IS published is what the pharmacy paid to acquire it: about $1.53 for 30, per the CMS NADAC survey. Treat that as the floor, not the quote — ask the pharmacist for the cash price as well as your copay, because for cheap generics the cash price often wins.
- Is there a coupon or discount for Phenergan?
- pharmaranks is an independent ratings site, not a pharmacy — we don't issue coupons or sell Phenergan. To pay less, ask your prescriber or pharmacist whether a generic equivalent exists, check the manufacturer's copay/savings card and patient-assistance program, and compare a pharmacy discount card against your insurance copay. Prices vary by pharmacy, insurance, and location, so always confirm at the counter. This is general reference, not medical or financial advice.
- Who makes Phenergan?
- Phenergan is marketed by Pharmobedient. You can see Pharmobedient's full profile, rating, and other products on pharmaranks.
- Is Phenergan a brand-name or generic drug?
- Phenergan is a brand-name product with the active ingredient Promethazine Hydrochloride. Lower-cost generic equivalents containing Promethazine Hydrochloride are available — ask your pharmacist.
- Is Phenergan available over the counter?
- No. Phenergan is a prescription (Rx) medication in the US — you need a prescription from a licensed clinician (in person or via telehealth); it isn't sold over the counter. For some conditions there are OTC alternatives — ask your pharmacist.
- What forms does Phenergan come in?
- Phenergan is currently marketed as injectable, per the FDA's National Drug Code Directory.
- What class of drug is Phenergan?
- Phenergan is classified as phenothiazine, per the FDA's Established Pharmacologic Class.
- Is Phenergan FDA-registered?
- Phenergan is on record with the U.S. FDA under application number NDA011689. You can verify this on its official FDA label.
- Is Phenergan safe?
- There's no single safe-or-not verdict, and we don't yet have a composite recall-safety score for Phenergan. Review its FDA-label side effects and warnings below, and always consult a licensed professional.
- What are the side effects of Phenergan?
- Phenergan's side effects are taken directly from its FDA label. From the label: Respiratory Depression PHENERGAN Injection is contraindicated in pediatric patients less than 2 years of age, because of the potential for fatal respiratory depression.… Both common and serious reactions are documented in full on this page. This is general reference from the FDA, not medical advice — always consult a professional.
Clinical content sourced from the FDA label via openFDA (U.S. FDA). View the FDA label on DailyMed → Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.
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