DrugindexOnline^{2nd edition}

Generic Name: Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) (gwye-FEN-e-sin/FEN-il-EF-rin)
Brand Name: Examples include Gentex LA and Liquibid-D

Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) is used for:

Relieving symptoms of congestion, cough, and throat and airway irritation due to colds, flu, or hay fever. It may also be used for other conditions as determined by your doctor.

Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) is a decongestant and expectorant combination. It works by constricting blood vessels and shrinking swollen and congested nasal tissues (mucous membranes) and by thinning and loosening mucus in the airway. This allows you to breathe more easily and makes coughs more productive.

Do NOT use Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) if:

• you are allergic to any ingredient in Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour)
• you have severe high blood pressure, severe heart blood vessel disease, rapid heartbeat, or severe heart problems
• you have taken furazolidone or a monoamine oxidase inhibitor (MAOI) (eg, phenelzine) within the last 14 days

Contact your doctor or health care provider right away if any of these apply to you.

Before using Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour):

Some medical conditions may interact with Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour). Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have a fast, slow, or irregular heartbeat
• if you have a history of adrenal gland problems (eg, tumor), heart problems, high blood pressure, diabetes, heart blood vessel problems, stroke, glaucoma, an enlarged prostate, seizures, or an overactive thyroid
• if you have chronic cough

Some MEDICINES MAY INTERACT with Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour). Tell your health care provider if you are taking any other medicines, especially any of the following:

• Beta-blockers (eg, propranolol), catechol-O-methyltransferase (COMT) inhibitors (eg, tolcapone), furazolidone, indomethacin, MAOIs (eg, phenelzine), or tricyclic antidepressants (eg, amitriptyline) because they may increase the risk of Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour)'s side effects
• Digoxin or droxidopa because the risk of irregular heartbeat or heart attack may be increased
• Bromocriptine because the risk of its side effects may be increased by Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour)
• Guanethidine, guanadrel, mecamylamine, methyldopa, or reserpine because their effectiveness may be decreased by Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour)

This may not be a complete list of all interactions that may occur. Ask your health care provider if Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour):

Use Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Take Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) by mouth with or without food. If stomach upset occurs, take with food to reduce stomach irritation.
• Take Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) with a full glass of water (8 oz/240 mL) unless your doctor directs otherwise.
• Swallow Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) whole. Do not break, crush, or chew before swallowing. Some brands of Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) may be broken in half before taking. If you have difficulty swallowing the whole tablet, ask your pharmacist if your brand of medicine may be broken in half.
• If you miss a dose of Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour), take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour).

Important safety information:

• Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) may cause dizziness. This effect may be worse if you take it with alcohol or certain medicines. Use Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
• Do not take diet or appetite control medicines while you are taking Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) without checking with you doctor.
• Do NOT take more than the recommended dose or use for longer than prescribed without checking with your doctor.
• Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) has phenylephrine in it. Before you start any new medicine, check the label to see if it has phenylephrine in it too. If it does or if you are not sure, check with your doctor or pharmacist.
• If your symptoms do not get better within 5 to 7 days or if they get worse, check with your doctor.
• Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) may interfere with certain lab tests. Be sure your doctor and lab personnel know you are taking Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour).
• Tell your doctor or dentist that you take Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) before you receive any medical or dental care, emergency care, or surgery.
• Use Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) with caution in the ELDERLY; they may be more sensitive to its effects.
• Caution is advised when using Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) in CHILDREN; they may be more sensitive to its effects.
• Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) should not be used in CHILDREN younger than 6 years old; safety and effectiveness in these children have not been confirmed
• PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) while you are pregnant. Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) is found in breast milk. Do not breast-feed while taking Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour).

Possible side effects of Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour):

All medicines may cause side effects, but many people have no, or minor, side effects. 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:

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.

This is not a complete list of all side effects that may occur. If you have questions or need medical advice about side effects, contact your doctor or health care provider. You may report side effects to the FDA at 1-800-FDA-1088 (1-800-332-1088) or at http://www.fda.gov/medwatch.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center (http://www.aapcc.org/findyour.htm), or emergency room immediately. Symptoms may include blurred vision; confusion; hallucinations; seizures; severe dizziness, lightheadedness, or headache; severe drowsiness; unusually fast, slow, or irregular heartbeat; vomiting.

Proper storage of Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour):

Store Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) out of the reach of children and away from pets.

General information:

• If you have any questions about Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour), please talk with your doctor, pharmacist, or other health care provider.
• Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour) is to be used only by the patient for whom it is prescribed. Do not share it with other people.
• If your symptoms do not improve or if they become worse, check with your doctor.

This information is a summary only. It does not contain all information about Guaifenesin/Phenylephrine Sustained-Release Tablets (12 Hour). If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.