We Mist II LA Side Effects

Generic Name: guaifenesin / pseudoephedrine

Note: This page contains side effects data for the generic drug guaifenesin / pseudoephedrine. It is possible that some of the dosage forms included below may not apply to the brand name We Mist II LA.

It is possible that some side effects of We Mist II LA 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 guaifenesin / pseudoephedrine: capsules, controlled-release capsules, liquid, sustained-release capsules, sustained-release tablets, syrup, tablets

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

Dizziness; excitability; headache; nausea; nervousness or anxiety; trouble sleeping; weakness.

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

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); difficulty urinating; fast or irregular heartbeat; hallucinations; seizures; severe dizziness, lightheadedness, or headache; tremor.

For Healthcare Professionals

Applies to guaifenesin / pseudoephedrine: oral capsule, oral capsule extended release, oral liquid, oral syrup, oral tablet, oral tablet chewable, oral tablet extended release


Cardiovascular side effects have included significant increases in heart rate. Hypertension and arrhythmias have also been problematic in susceptible patients.

Pseudoephedrine may cause vasoconstriction which generally does not produce hypertension, but may be problematic for patients with preexisting hypertension. Arrhythmias may be produced in predisposed patients. Rarely, pseudoephedrine has been reported to cause coronary artery spasm and chest pain.

Nervous system

Nervous system side effects of pseudoephedrine have included stimulation, resulting in tremor, anxiety, and nervousness. Insomnia has been reported in up to 30% of pseudoephedrine-treated patients. Headache has also been reported in patients receiving pseudoephedrine. Guaifenesin has occasionally caused dizziness and headache.


Gastrointestinal side effects associated with pseudoephedrine have included anorexia and gastric irritation in approximately 5% of patients. Dry mouth, nose, or throat has occurred in up to 15% of patients. Gastrointestinal upset and vomiting have been reported with higher than recommended doses of guaifenesin. Doses recommended for expectoration have rarely been associated with gastrointestinal upset.


Hypersensitivity side effects have included fixed drug eruptions secondary to pseudoephedrine.


Dermatologic side effects have included rare reports of rash.

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