Skip to Content

Dilex-G 400 Side Effects

Generic Name: dyphylline / guaifenesin

Note: This page contains information about the side effects of dyphylline / guaifenesin. Some of the dosage forms included on this document may not apply to the brand name Dilex-G 400.

For the Consumer

Applies to dyphylline / guaifenesin: capsules, elixir, liquid, syrup, tablets

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

Headache; nausea; upset stomach.

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

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blood in the urine; bloody vomit; diarrhea; dizziness; excitability; fast breathing; fast/irregular heartbeat; flushing; increased thirst or urination; irritability; muscle twitching; pounding in the chest; restlessness; seizures; stomach pain; trouble sleeping; vomiting.

For Healthcare Professionals

Applies to dyphylline / guaifenesin: oral capsule, oral liquid, oral syrup, oral tablet


Cardiovascular side effects have included palpitations, tachycardia, extrasystoles, flushing, hypotension, circulatory failure, and ventricular arrhythmias.[Ref]


Endocrine side effects have included hyperglycemia and inappropriate ADH syndrome.[Ref]


Gastrointestinal side effects have included nausea, vomiting, epigastric pain, hematemesis and diarrhea.[Ref]

Nervous system

Nervous system side effects have included headache, irritability, restlessness, insomnia, hyperexcitability, agitation, muscle twitching, and generalized clonic and tonic convulsions.[Ref]


Renal side effects have included albuminuria, diuresis and both gross and microscopic hematuria.[Ref]


1. "Product Information. Panfil G (dyphylline-guaifenesin)." Pamlab LLC, Mandeville, LA.

Not all side effects for Dilex-G 400 may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

More about Dilex-G 400 (dyphylline / guaifenesin)

Consumer resources

Other brands: COPD, Lufyllin-GG, Difil-G Forte, Jay-Phyl

Professional resources

Other Formulations

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.