What is promethazine?

Each 5 mL (teaspoonful) of Promethazine contains 6.25 mg of promethazine HCl. The inactive ingredients present are artificial banana flavor, artificial fruit flavor, artificial strawberry flavor, ascorbic acid, citric acid anhydrous, dehydrated alcohol, D&C Yellow No. 10, edetate disodium, FD&C Blue No. 1, FD&C Red No. 40, glycerin, sucrose, methylparaben, purified water, saccharin sodium, sodium benzoate, sodium citrate dihydrate, and sodium propionate. Promethazine HCl is a racemic compound; the molecular formula is C17H20N2S•HCl and its molecular weight is 320.88. Promethazine HCl, a phenothiazine derivative, is designated chemically as 10H-Phenothiazine-10-ethanamine, N,N, -trimethyl-, monohydrochloride, (±)- with the following structural formula: Promethazine HCl occurs as a white to faint yellow, practically odorless, crystalline powder which slowly oxidizes and turns blue on prolonged exposure to air. It is freely soluble in water and soluble in alcohol. Image

What kind of drug is promethazine?

The FDA classifies promethazine as a phenothiazine. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.

Can you take promethazine with other medicines?

It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run promethazine against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.

What brand names is promethazine sold under?

We track 4 promethazine-containing products in the U.S.: Phenergan, Promethazine Hydrochloride, Promethazine Plain and Promethegan. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.

What forms does promethazine come in?

Across the brands we track, promethazine is currently marketed as injectable, tablet, solution, suppository and syrup, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Is there a generic promethazine?

Yes. Our catalog lists 3 generic promethazine products alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.

Promethazine: uses, dosing, side effects & brands

Promethazine is a phenothiazine sold in the U.S. under 4 brand and generic names, for anaphylaxis, allergic conjunctivitis and motion sickness. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.

By the pharmaranks editorial teamReviewed against the FDA (openFDA label, NDC Directory & Enforcement) sourcesHow we research

Key facts

Drug class: Phenothiazine
Treats: Anaphylaxis, Allergic Conjunctivitis and Motion Sickness
Available as: Injectable · Tablet · Solution · Suppository · Syrup
Sold as: 4 products — Phenergan, Promethazine Hydrochloride and Promethazine Plain, and others
Prescription?: Prescription only
Generic available?: Yes
Typical price: about $2 for a 30-count supply
Boxed warning: Boxed warning

How promethazine is dosed

From the FDA label for Promethazine Plain (application ANDA087953). Other promethazine products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.

Promethazine Syrup is contraindicated for children under 2 years of age (see WARNINGS-Black Box Warning and Use in Pediatric Patients ). Allergy The average oral dose is 25 mg taken before retiring; however, 12.5 mg may be taken before meals and on retiring, if necessary. Single 25-mg doses at bedtime or 6.25 to 12.5 mg taken three times daily will usually suffice. After initiation of treatment in children or adults, dosage should be adjusted to the smallest amount adequate to relieve symptoms. The administration of promethazine HCl in 25-mg doses will control minor transfusion reactions of an allergic nature. Motion Sickness The average adult dose is 25 mg taken twice daily. The initial dose should be taken one-half to one hour before anticipated travel and be repeated 8 to 12 hours later, if necessary. On succeeding days of travel, it is recommended that 25 mg be given on arising and again before the evening meal. For children, Promethazine Syrup, 12.5 to 25 mg, twice daily, may be administered. Nausea and Vomiting Antiemetics should not be used in vomiting of unknown etiology in children and adolescents (see WARNINGS-Use in Pediatric Patients ). The average effective dose of Promethazine for the active therapy of nausea and vomiting in children or adults is 25 mg. When oral medication cannot be tolerated, the dose should be given parenterally (cf. Promethazine Injection) or…

Promethazine side effects

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 or decreased blood pressure, tachycardia, bradycardia, faintness. Dermatologic -Dermatitis, photosensitivity, urticaria. Hematologic -Leukopenia, thrombocytopenia, thrombocytopenic purpura, agranulocytosis. Gastrointestinal -Dry mouth, nausea, vomiting, jaundice. Respiratory -Asthma, nasal stuffiness, respiratory depression (potentially fatal) and apnea (potentially fatal). (See WARNINGS-Respiratory Depression .) Other -Angioneurotic edema. Neuroleptic malignant syndrome (potentially fatal) has also been reported. (See WARNINGS-Neuroleptic Malignant Syndrome .) Paradoxical Reactions Hyperexcitability and abnormal movements have been reported in patients following a single administration of promethazine HCl. Consideration should be given to the discontinuation of promethazine HCl and to the use of other drugs if these reactions occur. Respiratory depression, nightmares, delirium, and agitated behavior have…

Every promethazine product we track (4)

Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.

Promethazine products
#	Drug	Rating	Type	Form	Generic?	Typical price
1	Phenergan	Not yet rated	Prescription	Injectable	Generic	$2	View →
2	Promethazine Hydrochloride	Not yet rated	Prescription	Injectable	Generic	$2	View →

What promethazine pills look like

Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.

Promethazine pill imprints
Imprint	Strength	Colour	Shape	Maker
K;3	25 mg	white	round	—
K;2	12.5 mg	orange	round	—
K;3	25 mg	white	round	—
K;2	12.5 mg	orange	round	—

Combination products containing promethazine

A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.

Frequently asked questions

What is promethazine?: Each 5 mL (teaspoonful) of Promethazine contains 6.25 mg of promethazine HCl. The inactive ingredients present are artificial banana flavor, artificial fruit flavor, artificial strawberry flavor, ascorbic acid, citric acid anhydrous, dehydrated alcohol, D&C Yellow No. 10, edetate disodium, FD&C Blue No. 1, FD&C Red No. 40, glycerin, sucrose, methylparaben, purified water, saccharin sodium, sodium benzoate, sodium citrate dihydrate, and sodium propionate. Promethazine HCl is a racemic compound; the molecular formula is C17H20N2S•HCl and its molecular weight is 320.88. Promethazine HCl, a phenothiazine derivative, is designated chemically as 10H-Phenothiazine-10-ethanamine, N,N, -trimethyl-, monohydrochloride, (±)- with the following structural formula: Promethazine HCl occurs as a white to faint yellow, practically odorless, crystalline powder which slowly oxidizes and turns blue on prolonged exposure to air. It is freely soluble in water and soluble in alcohol. Image
What kind of drug is promethazine?: The FDA classifies promethazine as a phenothiazine. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take promethazine with other medicines?: It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run promethazine against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is promethazine sold under?: We track 4 promethazine-containing products in the U.S.: Phenergan, Promethazine Hydrochloride, Promethazine Plain and Promethegan. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does promethazine come in?: Across the brands we track, promethazine is currently marketed as injectable, tablet, solution, suppository and syrup, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.