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Triplex DM

Generic name: dextromethorphan hydrobromide, pyrilamine maleate, and phenylephrine hydrochloride
Dosage form: oral liquid

Medically reviewed by Last updated on Nov 23, 2020.

Disclaimer: This drug has not been found by FDA to be safe and effective, and this labeling has not been approved by FDA. For further information about unapproved drugs, click here.

Alcohol Free • Sugar Free • Dye Free

Triplex DM Description

Triplex™ DM Liquid is a grape flavored, alcohol free, sugar free, dye free liquid.

Each teaspoonful (5 mL.) contains:

Dextromethorphan Hydrobromide, USP 15 mg
Pyrilamine Maleate, USP 12.5 mg
Phenylephrine Hydrochloride, USP 7.5 mg


Sodium Benzoate, Citric Acid, Saccharin Sodium, Sorbitol Solution, Glycerin, Grape Flavor, Purified Water.

Dextromethorphan Hydrobromide is an antitussive which is a salt of the methyl ether of the dextrorotatory isomer of levorphanol, a narcotic analgesic. It's chemical name is Morphinan, 3-Methoxy-17-methyl-, (9α,13 α,14α)-, hydrobromide, monohydrate. It's structure is as follows:

C18H25NO ∙ HBr ∙ H2O M.W. 370.32

Pyrilamine Maleate is an antihistamine that occurs as a white crystalline powder, usually having a faint odor. It is very soluble in water, freely soluble in alcohol and chloroform, and slightly soluble in ether and benzene. It's chemical name is 1,2-Ethanediamine, N-[(4-methoxyphenyl)methyl]-N´,N´-dimethyl-N-2-pyridinyl-,(Z)-2-butenedioate (1:1). It's structure is as follows:

C17H23N3O.C4H4O4 M.W. 401.47

Phenylephrine Hydrochloride is an adrenergic that occurs as white or practically white, odorless crystals, having a bitter taste. It is freely soluble in water and in alcohol. It is affected by light. It's chemical name is Benzenemethanol, 3-hydroxy-α-[(methylamino)methyl]-, hydrochloride (R)-. It's structure is as follows:

C9H13NO2HCl M.W. 203.67

Triplex DM - Clinical Pharmacology

Dextromethorphan Hydrobromide is an antitussive which acts centrally to elevate the cough threshold. It has no analgesic or addictive properties. The onset of antitussive action occurs in 15 to 30 minutes after administration and is of long duration.

Pyrilamine Maleate is an antihistamine belonging to the ethylenediamine class. Pyrilamine is a highly effective H1 blocker which possesses local anesthetic activity. Pyrilamine antagonizes most of the smooth muscle stimulating actions of histamine on the H1 receptors of the gastrointestinal tract, blood vessels and bronchial muscle. It also antagonizes the actions of histamine that result in increased capillary permeability and the formation of edema. Pyrilamine has a duration of action of 4 to 6 hours in clinical studies.

Phenylephrine Hydrochloride, Phenylephrine is a potent postsynaptic alpha-receptor agonist with little effect on beta receptors of the heart. Phenylephrine has no effect on the beta- adrenergic receptors of the bronchi or peripheral blood vessels. A direct action at receptors accounts for the greater part of its effects: only a small part is due to its ability to release norepinephrine. Therapeutic doses of phenylephrine cause vasoconstriction. It increases resistance, and to a lesser extent, decreases capacitance of blood vessels. Total peripheral resistance is increased, resulting in increased systolic and diastolic blood pressure. Pulmonary arterial pressure is usually increased, and renal blood flow is usually decreased. Following oral administration of phenylephrine, constriction of blood vessels in the nasal mucosa relieves nasal congestion associated with allergy or head colds.

Following oral administration of phenylephrine, nasal decongestion may occur within 15 to 20 minutes and may persist for up to 4 hours. Phenylephrine is irregularly absorbed from and readily metabolized in the liver and intestine by monoamine oxidase. The metabolites and their route and rate of excretion have not been identified. The pharmacologic action of phenylephrine is terminated at least partially by uptake of the drug into the tissues.

Indications and Usage for Triplex DM

Triplex™ DM Liquid is indicated for allergic rhinitis and vasomotor rhinitis, allergy induced nasal congestion, such as runny nose, sneezing, and cough from inhalation of airborne antigens and other irritants.


Hypersensitivity to any of the ingredients. Patients known to be sensitive to other sympathomimetic amines may exhibit cross sensitivity with this drug. Triplex™ DM Liquid is contraindicated in patients with severe hypertension, severe coronary artery disease and patients on monoamine oxidase (MAO) inhibitor therapy (or for 14 days after stopping MAOI therapy). It is also contraindicated in patients with diabetes or hyperthyroidism. Antihistamines should not be administered to premature or newborn infants or be used to treat lower respiratory tract symptoms or asthma.


Pyrilamine Maleate

Antihistamines should be used with considerable caution in patients with narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, symptomatic prostatic hypertrophy, and bladder neck obstruction. In infants and children especially, antihistamine overdosage may cause hallucinations, convulsions or death. As in adults, antihistamines may diminish mental alertness in children. Patients should be warned about engaging in activities requiring mental alertness, such as driving a car or operating appliances and machinery. Do not exceed recommended dosage. If nervousness, dizziness, or sleeplessness occurs, discontinue use and consult a doctor. If symptoms do not improve within 7 days or are accompanied by a fever, consult a doctor.

Phenylephrine Hydrochloride

Sympathomimetic amines should be used with considerable caution in patients with hypertension, ischemic heart disease, diabetes mellitus, increased intraocular pressure, hyperthyroidism or prostatic hypertrophy. Sympathomimetics may produce central nervous system stimulation with convulsions or cardiovascular collapse with accompanying hypotension. DO NOT EXCEED RECOMMENDED DOSAGE. Hypertensive crisis could occur with concurrent use of phenylephrine and monoamine oxidase (MAO) inhibitors (or for 14 days after stopping MAOI therapy), indomethacin or with betablockers and methyldopa. If a hypertensive crisis occurs, this drug should be discontinued immediately and therapy to lower blood pressure should be instituted. Fever should be managed by means of external cooling. The elderly (approximately sixty years or older) are more likely to have adverse reactions to sympathomimetics. Overdosage of sympathomimetics in this age group may cause hallucinations, convulsions, CNS depression and death.

Do not exceed recommended doses. Discontinue use if adverse reaction(s) occur.



Antihistamines have an atropine like action and therefore should be used with caution in patients with a history of bronchial asthma, increased intraocular pressure, hyperthyroidism, cardiovascular disease and hypertension. Phenylephrine should be used with caution in patients with diabetes, hypertension, cardiovascular disease and hyperreactivity to ephedrine.


Antihistamines may impair the mental and physical abilities required for the performance of potentially hazardous tasks such as driving a vehicle or operating machinery. Patients should also be warned about possible additive effects with alcohol and other central nervous system depressants (hypnotics, sedatives, and tranquilizers). Stimulants, such as phenylephrine, are banned and tested for by the U.S. Olympic Committee and the National Collegiate Athletic Association (NCAA).

Drug Interactions

MAO inhibitors (or for 14 days after stopping MAOI therapy) and tricyclic antidepressants may prolong and intensify the anticholinergic (drying) effects of antihistamines. Serious toxicity may result if dextromethorphan is co-administered with monoamine oxidase (MAO) inhibitors (or for 14 days after stopping MAOI therapy). Beta-adrenergic blockers and MAO inhibitors (or for 14 days after stopping MAOI therapy) may potentiate the pressor effect of phenylephrine. Concurrent use of digitalis glycosides may increase the possibility of cardiac arrhythmias. Sympathomimetics may reduce the antihypertensive effects of methyldopa, mecamylamine, reserpine and veratrum alkaloids. Concurrent use of tricyclic antidepressants may antagonize the effects of phenylephrine. Use of antihistamines with alcohol, tricyclic antidepressants, barbiturates, and other CNS depressants may have an addictive effect.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No long-term studies have been performed using Triplex™ DM Liquid to determine the potential for carcinogenesis, mutagenesis and impairment of fertility. In a four-year evaluation of phenylephrine, no statistically significant association between the drug and cancer was found.

Usage in Pregnancy


Category C

Moderate overexposure to phenylephrine has been found to contribute to birth defects in rabbits. Animal reproduction studies have not been conducted with the other ingredients in Triplex™ DM Liquid. Triplex™ DM Liquid should be used during pregnancy only if the potential benefit justifies the possible risk to the fetus.

Labor and Delivery

Administration of phenylephrine to patients in late pregnancy or labor may cause fetal anoxia or bradycardia by increasing contractility of the uterus and decreasing uterine blood flow.

Nursing Mothers

Due to the possible passage of antihistamines into breast milk, and because of the higher than usual risk for infants from sympathomimetic amines and antihistamines, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of both.

Pediatric Use

Safety and effectiveness in the pediatric population, under 6, have not been established. In infants and children especially, antihistamine overdosage may cause hallucinations, convulsions or death. As in adults, antihistamines may diminish mental alertness in children. In the young child particularly, antihistamines may produce excitation.

Geriatric Use

The elderly (60 years of age and older) are more likely to experience adverse reactions from sympathomimetics and antihistamines. Overdosage of sympathomimetics in this age group may cause hallucinations, convulsions, CNS depression and death.

Adverse Reactions

Dextromethorphan Hydrobromide

Adverse effects with dextromethorphan are rare, but nausea and/or other gastrointestinal disturbances, slight dizziness and drowsiness sometimes occur.

Pyrilamine Maleate

Possible side effects of antihistamines in general include: urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of the mouth, nose and throat; cardiovascular effects (hypotension, headache, palpitation, tachycardia, extrasystoles); hematological effects (hemolytic anemia, thrombocytopenia, agranulocytosis); CNS disturbances (sedation, dizziness, disturbed coordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paresthesias, blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, hysteria, neuritis, convulsions); gastrointestinal effects (epigastric distress, anorexia, nausea, vomiting, diarrhea, constipation); genitourinary effects (urinary frequency, difficult urination, urinary retention, early menses) and respiratory effects (thickening of bronchial secretions, tightness of the chest, wheezing and nasal stuffiness).

Phenylephrine Hydrochloride

Hyperreactive individuals may display ephedrine-like reactions such as tachycardia, palpitations, headache, dizziness or nausea. Sympathomimetic amines have been associated with certain untoward reactions including fear, anxiety, nervousness, restlessness, tremor, weakness, pallor, respiratory difficulty, dysuria, insomnia, hallucinations, convulsions, CNS depression, arrhythmias, and cardiovascular collapse with hypotension. Phenylephrine may cause precordial pain, respiratory distress, tremor, weakness, hypertension, restlessness, anxiety, nervousness and dizziness.


Signs and Symptoms

Dextromethorphan Hydrobromide

May produce excitement and mental confusion. Very high doses may produce respiratory depression. One case of toxic psychosis (hyperactivity, marked visual and auditory hallucinations) after ingestion of a single 300 mg dose of dextromethorphan has been reported.

Pyrilamine Maleate

Manifestations of antihistamine overdosage may vary from central nervous system depression (sedation, apnea, cardiovascular collapse) to stimulation (insomnia, hallucinations, tremors or convulsions). Other signs and symptoms may be dizziness, tinnitus, ataxia, blurred vision and hypotension. Stimulation is particularly likely in children, as are atropine like signs and symptoms (dry mouth, fixed dilated pupils, flushing, hyperthermia and gastrointestinal symptoms).

Phenylephrine Hydrochloride

May cause hypertension, headache, convulsions, cerebral hemorrhage and vomiting. Ventricular premature beats and short paroxysms of ventricular tachycardia may also occur. Headache may be a symptom of hypertension. Bradycardia may also be seen early in phenylephrine overdosage through stimulation of baroreceptors. Excessive CNS stimulation may result in excitement, tremor, restlessness, and insomnia. Other effects may include pallor, mydriasis, hyperglycemia and urinary retention. Severe overdosage may cause tachypnea or hypernea, hallucination, convulsions or delirium but in some individuals, there may be CNS depression with somnolence, stupor or respiratory depression. Arrhythmias (including ventricular fibrillation) may lead to hypotension and circulatory collapse. Severe hypokalemia can occur, probably due to compartmental shift rather than a depletion of potassium.


The patient should be induced to vomit even if emesis has occurred spontaneously. Pharmacologic vomiting by the administration of ipecac is facilitated by physical activity and by the administration of eight to twelve ounces of water. If emesis does not occur within fifteen minutes, the dose of ipecac should be repeated.

Precautions against aspiration must be taken especially in infants and children. Following emesis, any drug remaining in the stomach may be absorbed by activated charcoal administered as a slurry with water. If vomiting is unsuccessful or contraindicated, gastric lavage should be performed. Isotonic and one-half isotonic saline are the lavage solutions of choice. Saline cathartics, such as milk of magnesia, draw water into the bowel by osmosis and, therefore, may be valuable for their action in rapid dilution of bowel content. After emergency treatment, the patient should continue to be medically monitored. Treatment of the signs and symptoms of overdosage is symptomatic and supportive.

Triplex DM Dosage and Administration

Adults and Children 12 years of age or older

1-2 teaspoonfuls every 4 to 6 hours or as directed by a physician, not to exceed 60 mg of Phenylephrine HCl in a 24-hour period.

Children 6 to 12 years of age

½ - 1 teaspoonful every 4 - 6 hours or as directed by a physician, not to exceed 30 mg of Phenylephrine HCl in a 24-hour period. This product is not indicated for use in children under 6 years of age. (see PRECAUTIONS, Pediatric Use.)

How Supplied

Triplex™ DM Liquid is a clear, grape flavored, sugar free, alcohol free, dye free liquid supplied in 16 fl. oz. bottles, NDC 51991-493-16.

Dispense in a tight, light-resistant container with a child-resistant closure as defined in the USP/NF.

Store at 25°C (77°F); excursions permitted to 15°-30°C (59°-86°F). See USP Controlled Room Temperature Protect from freezing.

All prescription substitutions using this product shall be pursuant to state statues as applicable.
This is not an Orange Book product.

Keep this and all medications out of the reach of children. In case of accidental overdose, seek professional assistance or contact a Poison Control Center immediately.

Rx Only

Manufactured by: Tri-Med Laboratories, Inc., Somerset, NJ 08873

Distributed by: Breckenridge Pharmaceutical, Inc., Boca Raton, FL 33487

ISS. 12/06
Rev. 4/08


Pharmaceutical, Inc.

NDC 51991-493-16

Triplex DM

  • Sugar Free
  • Alcohol Free
  • Dye Free

Description: Each 5 mL (one teaspoonful) for oral
administration contains:

Dextromethorphan Hydrobromide 15 mg
Pyrilamine Maleate 12.5 mg
Phenylephrine Hydrochloride 7.5 mg

Citric Acid, Saccharin Sodium, Sorbitol Solution,
Glycerin, Grape Flavor, Purified Water.

Rx Only

Net Contents:
16 fl oz (One Pint) 473 mL

Triplex DM
dextromethorphan hydrobromide, pyrilamine maleate, and phenylephrine hydrochloride liquid
Product Information
Product Type HUMAN PRESCRIPTION DRUG LABEL Item Code (Source) NDC:51991-493
Route of Administration ORAL DEA Schedule
Active Ingredient/Active Moiety
Ingredient Name Basis of Strength Strength
Dextromethorphan Hydrobromide (Dextromethorphan) Dextromethorphan Hydrobromide 15 mg in 5 mL
Pyrilamine Maleate (Pyrilamine) Pyrilamine Maleate 12.5 mg in 5 mL
Phenylephrine Hydrochloride (Phenylephrine) Phenylephrine Hydrochloride 7.5 mg in 5 mL
Inactive Ingredients
Ingredient Name Strength
Sodium Benzoate
Citric Acid Monohydrate
Saccharin Sodium
Product Characteristics
Color WHITE (Clear) Score
Shape Size
Flavor GRAPE Imprint Code
# Item Code Package Description
1 NDC:51991-493-16 473 mL in 1 BOTTLE
Marketing Information
Marketing Category Application Number or Monograph Citation Marketing Start Date Marketing End Date
UNAPPROVED DRUG OTHER 02/01/2007 11/30/2011
Labeler - Breckenridge Pharmaceutical, Inc. (150554335)
Name Address ID/FEI Operations
Tri-Med 182050567 MANUFACTURE
Breckenridge Pharmaceutical, Inc.

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