Skip to Content

Phencarb GG Side Effects

Generic Name: carbetapentane / guaifenesin / phenylephrine

Note: This page contains side effects data for the generic drug carbetapentane / guaifenesin / phenylephrine. It is possible that some of the dosage forms included below may not apply to the brand name Phencarb GG.

It is possible that some side effects of Phencarb GG may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to carbetapentane / guaifenesin / phenylephrine: sustained-release tablets

Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Diarrhea; dizziness; drowsiness; excitability; headache; irritability; nausea; stomach upset; trouble sleeping.

Seek medical attention right away if any of these SEVERE side effects occur while taking carbetapentane / guaifenesin / phenylephrine:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); difficulty urinating; fast, slow, or irregular heartbeat; fever; hallucinations; mental or mood changes (eg, anxiety, nervousness); paleness; seizures; severe or persistent dizziness, lightheadedness, or headache; tremor.

For Healthcare Professionals

Applies to carbetapentane / guaifenesin / phenylephrine: oral liquid, oral syrup, oral tablet, oral tablet extended release

Nervous system

Nervous system side effects have included nervousness, lightheadedness, excitability, restlessness, dizziness, tenseness, convulsions, CNS depression, and insomnia.[Ref]


Cardiovascular side effects have included arrhythmias and hypotension with cardiovascular collapse.[Ref]


Gastrointestinal side effects have included nausea and vomiting.[Ref]


Psychiatric side effects have included fear, anxiety, and hallucinations.[Ref]


Respiratory side effects have included respiratory difficulty.[Ref]


Genitourinary side effects have included dysuria.[Ref]


General side effects have included weakness and pallor.[Ref]


1. "Product Information. Phencarb GG (carbetapentane / guaifenesin / phenylephrine)." Boca Pharmacal Inc, Coconut Creek, FL.

More about Phencarb GG (carbetapentane / guaifenesin / phenylephrine)

Consumer resources

Related treatment guides

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.