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M-Phen Side Effects

Generic Name: codeine / phenylephrine / promethazine

Note: This document contains side effect information about codeine / phenylephrine / promethazine. Some of the dosage forms listed on this page may not apply to the brand name M-Phen.

For the Consumer

Applies to codeine / phenylephrine / promethazine: oral elixir, oral syrup

Along with its needed effects, codeine / phenylephrine / promethazine 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 immediately if any of the following side effects occur while taking codeine / phenylephrine / promethazine:

Incidence not known
  • Abdominal or stomach pain
  • black, tarry stools
  • bleeding gums
  • bloating
  • blood in the urine or stools
  • blurred vision
  • chest pain
  • chills
  • clay-colored stools
  • cold sweats
  • confusion
  • constipation
  • convulsions
  • cough
  • dark urine
  • decrease in the frequency of urination
  • decrease in urine volume
  • difficult or troubled breathing
  • difficulty in passing urine (dribbling)
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up from lying or sitting position
  • fainting
  • fast, pounding, or irregular heartbeat or pulse
  • fever
  • headache
  • high fever
  • increased sweating
  • irregular, fast or slow, or shallow breathing
  • lightheadedness
  • loss of appetite
  • loss of bladder control
  • nausea or vomiting
  • nervousness
  • painful or difficult urination
  • pale or blue lips, fingernails, or skin
  • pinpoint red spots on the skin
  • pounding in the ears
  • rash or itching
  • severe muscle stiffness
  • shakiness in the legs, arms, hands, or feet
  • slow or fast heartbeat
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • swollen glands
  • tiredness
  • trembling or shaking of the hands or feet
  • unpleasant breath odor
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • unusually pale skin
  • vomiting of blood
  • yellow eyes or skin

Some side effects of codeine / phenylephrine / 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:

More common
  • Drowsiness
Incidence not known
  • Anxiety
  • blurred or loss of vision
  • confusion
  • confusion about identity, place, and time
  • constipation
  • disturbed color perception
  • double vision
  • dry mouth
  • false or unusual sense of well-being
  • halos around lights
  • increased sensitivity of the skin to sunlight
  • night blindness
  • overbright appearance of lights
  • redness or other discoloration of the skin
  • relaxed and calm
  • restlessness
  • seeing, hearing, or feeling things that are not there
  • severe sunburn
  • sleepiness or unusual drowsiness
  • trouble sleeping
  • tunnel vision

For Healthcare Professionals

Applies to codeine / phenylephrine / promethazine: oral syrup

General

The more commonly reported adverse effects have included nausea, vomiting, constipation, blurred vision, confusion, and dizziness.[Ref]

Respiratory

Codeine:
Frequency not reported: Respiratory depression

Phenylephrine:
Frequency not reported: Respiratory distress

Promethazine:
Frequency not reported: Asthma, nasal stuffiness, respiratory depression, apnea[Ref]

Concomitant administration of promethazine with other respiratory depressants has been associated with respiratory depression, including fatalities. Postmarketing cases in pediatric patients less than 2 years of age has been reported with a wide range of weight-based doses. Respiratory depression has been associated with antitussive use of codeine in young children.

Respiratory depression and death have occurred in children who received codeine in the postoperative period following tonsillectomy and/or adenoidectomy. Further investigation has shown these patients to be ultra-rapid metabolizers of codeine. Children with obstructive sleep apnea who are treated with codeine appear to be particularly sensitive to the respiratory depressant effects of codeine.[Ref]

Cardiovascular

Codeine:
Frequency not reported: Tachycardia, bradycardia, palpitation, faintness, syncope, orthostatic hypotension, circulatory depression

Phenylephrine:
Frequency not reported: Ischemia

Promethazine:
Frequency not reported: Increased or decreased blood pressure, tachycardia,
bradycardia, faintness[Ref]

Ischemia with risk of gangrene or thrombosis of compromised vascular may result with phenylephrine use.[Ref]

Nervous system

Codeine:
Frequency not reported: CNS depression, lightheadedness, dizziness, sedation, headache, convulsions, weakness

Phenylephrine:
Frequency not reported: Restlessness, dizziness, tremor, weakness

Promethazine:
Frequency not reported: Drowsiness, sedation, somnolence, extra-pyramidal symptoms, torticollis, tongue protrusion, incoordination, tremors, seizures, neuroleptic malignant syndrome, paradoxical reactions[Ref]

Promethazine use has resulted in paradoxical reactions described as hyperexcitability and abnormal movements. This has occurred following 1 dose and in some patients accompanied by respiratory depression, nightmares, delirium, and agitated behavior.[Ref]

Psychiatric

Codeine:
Frequency not reported: Euphoria, dysphoria, transient hallucination, disorientation

Phenylephrine:
Frequency not reported: Anxiety, nervousness

Promethazine:
Frequency not reported: Confusion, disorientation, euphoria, nervousness, insomnia, excitation, catatonic-like states, hysteria, hallucinations[Ref]

Gastrointestinal

Codeine:
Frequency not reported: Nausea, vomiting, constipation, biliary tract spasm, increased colonic motility, toxic dilation

Patients with chronic ulcerative colitis may experience increased colonic motility, while patients with acute ulcerative colitis have experienced toxic dilation with codeine use.

Promethazine:
Frequency not reported: Dry mouth, nausea, vomiting[Ref]

Hypersensitivity

The syrup contains sodium metabisulfite, a sulfite that may cause allergic-type reactions in susceptible people. Allergic type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes are possible.[Ref]

Codeine:
Frequency not reported: Pruritus, giant urticaria, angioneurotic edema, laryngeal edema

Promethazine:
Frequency not reported: Angioneurotic edema

Sodium Metabisulfite:
Frequency not reported: Anaphylaxis[Ref]

Other

Phenylephrine:
Frequency not reported: Pain

Promethazine:
Frequency not reported: Lassitude, tinnitus, fatigue[Ref]

Genitourinary

Codeine:
Frequency not reported: Oliguria, urinary retention, antidiuretic effect[Ref]

Dermatologic

Promethazine:
Frequency not reported: Dermatitis, photosensitivity, urticaria[Ref]

Hematologic

Promethazine:
Frequency not reported: Leukopenia, thrombocytopenia, thrombocytopenic purpura, agranulocytosis[Ref]

Hepatic

Promethazine:
Frequency not reported: Cholestatic jaundice[Ref]

Metabolic

Promethazine:
Frequency not reported: Hyperglycemia[Ref]

Ocular

Codeine:
Frequency not reported: Visual disturbances

Promethazine:
Frequency not reported: Blurred vision, oculogyric crisis, diplopia[Ref]

References

1. "Product Information. Codeine Phosphate/PE/Promethazine HCl (codeine / phenylephrine / promethazine)." Amneal Pharmaceuticals, Glasgow, KY.

Some side effects of M-Phen may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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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