Do not take this medication with any of the following medicines:

-alcohol
-antihistamines for allergy, cough and cold
-certain medicines for anxiety or sleep
-certain medicines for depression like amitriptyline, fluoxetine, sertraline
-certain medicines for seizures like carbamazepine, phenobarbital, phenytoin, primidone
-general anesthetics like halothane, isoflurane, methoxyflurane, propofol
-local anesthetics like lidocaine, pramoxine, tetracaine
-MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate
-medicines that relax muscles for surgery
-other narcotic medicines (opiates) for pain or cough
-phenothiazines like chlorpromazine, mesoridazine, prochlorperazine, thioridazine

This medicine may also interact with the following medications:

-antiviral medicines for HIV or AIDS
-atropine
-certain antibiotics like erythromycin and clarithromycin
-certain medicines for bladder problems like oxybutynin, tolterodine
-certain medicines for fungal infections like ketoconazole and itraconazole
-certain medicines for irregular heart beat like amiodarone, propafenone, quinidine
-certain medicines for Parkinson''s disease like benztropine, trihexyphenidyl
-certain medicines for stomach problems like dicyclomine, hyoscyamine
-certain medicines for travel sickness like scopolamine
-ipratropium
-rifampin

They need to know if you have any of these conditions:

-Addison''s disease
-brain tumor
-gallbladder disease
-head injury
-heart disease
-history of a drug or alcohol abuse problem
-history of irregular heartbeat
-if you often drink alcohol
-kidney disease
-liver disease
-low blood pressure
-lung or breathing disease, like asthma
-mental illness
-pancreatic disease
-seizures
-stomach or intestine problems
-thyroid disease
-trouble passing urine
-an allergic or unusual reaction to guaifenesin, codeine, other medicines, foods, dyes, or preservatives
-pregnant or trying to get pregnant
-breast-feeding

Use exactly as directed by your doctor or health care professional. Do not take more than the recommended dose. You may develop tolerance to this medicine if you take it for a long time. Tolerance means that you will get less cough relief with time. Tell your doctor or health care professional if your symptoms do not improve or if they get worse.

If you have been taking this medicine for a long time, do not suddenly stop taking it because you may develop a severe reaction. Your body becomes used to the medicine. This does NOT mean you are addicted. Addiction is a behavior related to getting and using a drug for a nonmedical reason. If your doctor wants you to stop the medicine, the dose will be slowly lowered over time to avoid any side effects.

There are different types of narcotic medicines (opiates). If you take more than one type at the same time or if you are taking another medicine that also causes drowsiness, you may have more side effects. Give your health care provider a list of all medicines you use. Your doctor will tell you how much medicine to take. Do not take more medicine than directed. Call emergency for help if you have problems breathing or unusual sleepiness.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

The medicine may cause constipation. Try to have a bowel movement at least every 2 to 3 days. If you do not have a bowel movement for 3 days, call your doctor or health care professional.

Your mouth may get dry. Chewing sugarless gum or sucking hard candy, and drinking plenty of water may help. Contact your doctor if the problem does not go away or is severe.

Keep out of the reach of children. This medicine can be abused. Keep your medicine in a safe place to protect it from theft. Do not share this medicine with anyone. Selling or giving away this medicine is dangerous and against the law.

Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Protect from light. This medicine may cause accidental overdose and death if taken by other adults, children, or pets. Mix any unused medicine with a substance like cat littler or coffee grounds. Then throw the medicine away in a sealed container like a sealed bag or a coffee can with a lid. Do not use the medicine after the expiration date.