Guaifenex RX Side Effects
Generic Name: guaifenesin / pseudoephedrine
Note: This document contains side effect information about guaifenesin / pseudoephedrine. Some of the dosage forms listed on this page may not apply to the brand name Guaifenex RX.
For the Consumer
Applies to guaifenesin / pseudoephedrine: oral capsule, oral liquid, oral syrup, oral tablet, oral tablet extended release 12 hour
What are some side effects that I need to call my doctor about right away?
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
What are some other side effects of this drug?
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Feeling nervous and excitable.
- Not able to sleep.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.
For Healthcare Professionals
Cardiovascular side effects have included significant increases in heart rate. Hypertension and arrhythmias have also been problematic in susceptible patients.[Ref]
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.[Ref]
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.[Ref]
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.[Ref]
Hypersensitivity side effects have included fixed drug eruptions secondary to pseudoephedrine.[Ref]
Dermatologic side effects have included rare reports of rash.[Ref]
1. Gordon RD, Ballantine DM, Bachmann AW "Effects of repeated doses of pseudoephedrine on blood pressure and plasma catecholamines in normal subjects and in patients with phaeochromocytoma." Clin Exp Pharmacol Physiol 19 (1992): 287-90
2. Dickerson J, Perrier D, Mayersohn M, Bressler R "Dose tolerance and pharmacokinetic studies of L (+) pseudoephedrine capsules in man." Eur J Clin Pharmacol 14 (1978): 253-9
3. Rosen RA "Angina associated with pseudoephedrine ." Ann Emerg Med 10 (1981): 230-1
4. Wiener I, Tilkian AG, Palazzolo M "Coronary artery spasm and myocardial infarction in a patient with normal coronary arteries: temporal relationship to pseudoephedrine ingestion." Cathet Cardiovasc Diagn 20 (1990): 51-3
5. Mariani PJ "Pseudoephedrine-induced hypertensive emergency: treatment with labetalol." Am J Emerg Med 4 (1986): 141-2
6. Stroh JE, Jr Ayars GH, Bernstein IL, Kemp JP, Podleski WK, Prenner BM, Schoenwetter WF, Salzmann JK "A comparative tolerance study of terfenadine-pseudoephedrine combination tablets and pseudoephedrine tablets in patients with allergic or vasomotor rhinitis." J Int Med Res 16 (1988): 420-7
7. Covington TR, Lawson LC, Young LL, eds. "Handbook of Nonprescription Drugs. 10th ed." Washington, DC: American Pharmaceutical Association (1993):
8. "Product Information. Robitussin (guaifenesin)." Wyeth-Ayerst Laboratories, Philadelphia, PA.
9. Loizou LA, Hamilton JG, Tsementzis SA "Intracranial haemorrhage in association with pseudoephedrine overdose." J Neurol Neurosurg Psychiatry 45 (1982): 471-2
10. Quan MB, Chow WC "Nonpigmenting fixed drug eruption after pseudoephedrine." Int J Dermatol 35 (1996): 367-70
11. Camisa C "Fixed drug eruption due to pseudoephedrine." Cutis 41 (1988): 339-40
12. Tomb RR, Lepoittevin JP, Espinassouze F, Heid E, Foussereau J "Systemic contact dermatitis from pseudoephedrine." Contact Dermatitis 24 (1991): 86-8
13. Shelley WB, Shelley ED "Nonpigmenting fixed drug eruption as a distinctive reaction pattern: examples caused by sensitivity to pseudoephedrine hydrochloride and tetrahydrozoline." J Am Acad Dermatol 17 (1987): 403-7
Some side effects may not be reported. You may report them to the FDA.
More about Guaifenex RX (guaifenesin / pseudoephedrine)
- During Pregnancy
- Dosage Information
- Drug Interactions
- Drug class: upper respiratory combinations
- FDA Alerts (1)