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Hycofenix Side Effects

Generic Name: guaifenesin / hydrocodone / pseudoephedrine

Note: This document contains side effect information about guaifenesin / hydrocodone / pseudoephedrine. Some of the dosage forms listed on this page may not apply to the brand name Hycofenix.

For the Consumer

Applies to guaifenesin / hydrocodone / pseudoephedrine: oral elixir, oral liquid, oral solution, oral syrup, oral tablet

Along with its needed effects, guaifenesin/hydrocodone/pseudoephedrine 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 guaifenesin/hydrocodone/pseudoephedrine:

Incidence not known
  • Abdominal or stomach cramps or pain
  • bloating
  • blurred vision
  • chest pain or discomfort
  • cold, clammy, pale skin
  • confusion
  • constipation
  • convulsions
  • diarrhea
  • difficult or troubled breathing
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fainting
  • fast, slow, or irregular heartbeat
  • irregular, fast or slow, or shallow breathing
  • pale or blue lips, fingernails, or skin
  • shakiness in the legs, arms, hands, or feet
  • slow heart rate
  • sweating
  • trembling or shaking of the hands or feet
  • unusual tiredness or weakness
  • vomiting

Some side effects of guaifenesin/hydrocodone/pseudoephedrine 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
  • Diarrhea
  • drowsiness
  • feeling of warmth
  • headache
  • nausea
  • redness of the face, neck, arms, and occasionally, upper chest
  • relaxed and calm
  • sleepiness
  • sudden sweating
Incidence not known
  • Trouble sleeping

For Healthcare Professionals

Applies to guaifenesin / hydrocodone / pseudoephedrine: oral liquid, oral tablet


The most commonly reported adverse effects have included headache, dizziness, sedation, nausea, diarrhea, decreased blood pressure, and flushing.[Ref]


Frequency not reported: Dose-related respiratory depression including fatal respiratory depression


Frequency not reported: Fast, slow heartbeat, hypertension, hypotension, orthostatic hypotension, palpitation, shock-like state, syncope, arrhythmia


Frequency not reported: Insomnia, mental clouding, anxiety, fear, dysphoria, drug dependence, mood changes, sleeplessness

Nervous system

Frequency not reported: Sedation (somnolence), headache, dizziness, weakness, decreased mental alertness with impaired mental and/or physical abilities

Frequency not reported: Increased intracranial pressure

Frequency not reported: Convulsions


Frequency not reported: Nausea, vomiting, diarrhea, constipation

Frequency not reported: Paralytic ileus


Frequency not reported: Skin rash, pruritus, hot flush


1. "Product Information. Dynex HD (guaifenesin / hydrocodone / pseudoephedrine)." Athlon Pharmaceuticals Inc, Birmingham, AL.

2. "Product Information. Hycofenix (guaifenesin / hydrocodone / pseudoephedrine)." Mission Pharmacal Company, San Antonio, TX.

3. "Product Information. Entex HC (guaifenesin / hydrocodone / pseudoephedrine)." Athlon Pharmaceuticals Inc, Birmingham, AL.

Some side effects of Hycofenix 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. 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.