Mytussin AC (Generic)

This combination medication is used to temporarily treat coughing and chest congestion symptoms caused by the common cold, flu, or other breathing illnesses (e.g., sinusitis, bronchitis). Guaifenesin is an expectorant that helps thin and loosen mucus in the lungs, making it easier to cough up the mucus. Codeine is an opioid cough suppressant (antitussive) that affects a certain part of the brain, reducing the urge to cough.

This medication is not usually used for ongoing coughs from smoking, asthma, other long-term breathing problems (e.g., emphysema), or for coughs with a lot of mucus, unless directed by your doctor.

Opioid cough suppressants should not be used in children younger than 18 years. Children are at higher risk for serious (even fatal) side effects, especially breathing problems. Talk with the doctor about the risks and benefits of this medication.

Cough-and-cold products do not cure colds. Cough due to a common cold often does not need to be treated with medicine. Ask your doctor or pharmacist about other ways to relieve cough and cold symptoms, such as drinking enough fluids, using a humidifier, or saline nose drops/spray.

Take this medication by mouth with or without food, usually every 4 to 6 hours as needed with a full glass of water (8 ounces or 240 milliliters) or as directed by your doctor. This medication can be taken with food if stomach upset occurs. Drink plenty of fluids while you are using this medication unless otherwise directed by your doctor. The fluid will help loosen the mucus in your lungs.

If you are using the liquid form of this medication, carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.

Some liquids need to be shaken before pouring each dose. Check your bottle or ask your pharmacist if your product needs to be shaken.

Do not increase your dose or use this product more often or for longer than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.

If you suddenly stop using this medication, you may have withdrawal symptoms (such as restlessness, watering eyes, runny nose, nausea, sweating, muscle aches). To help prevent withdrawal, your doctor may lower your dose slowly. Withdrawal is more likely if you have used this medication for a long time (more than a few weeks) or in high doses. Tell your doctor or pharmacist right away if you have withdrawal.

Though it helps many people, this product has a risk for abuse and may sometimes cause addiction. This risk may be higher if you have a substance use disorder (such as overuse of or addiction to drugs/alcohol). Take this product exactly as prescribed to lower the risk of addiction. Ask your doctor or pharmacist for more details.

When used for an extended time, this medication may not work as well and may require different dosing. Talk with your doctor if this medication stops working well.

Tell your doctor if your cough does not get better in 5 days. Also, tell your doctor if your condition gets worse, or if you have a fever, rash, or persistent headache. These may be symptoms of a serious medical problem and should be checked by a doctor.

See also Warning section.

Drowsiness, dizziness, lightheadedness, facial flushing, nausea, vomiting, or constipation may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: interrupted breathing during sleep (sleep apnea), mental/mood changes (e.g., hallucinations), fast/irregular heartbeat, trouble urinating.

Get medical help right away if you have any very serious side effects, including: seizure.

Codeine is changed into a strong opioid drug (morphine) in your body. In some people, this change happens faster and more completely than usual, which increases the risk of very serious side effects. Get medical help right away if you notice any of the following: slow/shallow breathing, severe drowsiness/difficulty waking up, confusion.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other side effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking this medication, tell your doctor or pharmacist if you are allergic to any of its ingredients; or to opioid pain relievers (e.g., morphine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: abdominal problems (e.g., chronic constipation, ileus, gallbladder disease, pancreatitis), adrenal gland problem (e.g., Addison's disease), brain disorders (e.g., seizures, head injury, tumor, increased intracranial pressure), breathing problems (e.g., asthma, emphysema, sleep apnea), heart problems (e.g., irregular heartbeat), kidney disease, liver disease, mental/mood disorders (e.g., depression, psychosis), obesity, a certain spinal problem (kyphoscoliosis), underactive thyroid (hypothyroidism), trouble urinating (e.g., due to enlarged prostate or urethral stricture), personal or family history of a substance use disorder (such as overuse of or addiction to drugs/alcohol).

This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

To reduce dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Liquid forms of this medication may contain sugar, alcohol, or aspartame. Caution is advised if you have diabetes, alcohol dependence, liver disease, phenylketonuria (PKU), or any other condition that requires you to monitor/avoid these substances in your diet. Consult your doctor or pharmacist about using this medication safely.

Older adults may be more sensitive to the side effects of this drug, especially confusion, dizziness, drowsiness, and slow/shallow breathing.

Tell your doctor if you are pregnant or think you may be pregnant. During pregnancy, this product is not recommended. It may harm an unborn baby. Talk to your doctor about the risks and benefits of this medication. See also Warning section.

This product passes into breast milk and may have undesirable effects on a nursing infant (such as unusual sleepiness, difficulty feeding, trouble breathing, or unusual limpness). Breast-feeding while using this product is not recommended. Consult your doctor before breast-feeding.

Store at room temperature away from light and moisture. Do not store in the bathroom. Do not freeze liquid forms of this medication. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

See also Warning section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include: cimetidine, naltrexone.

Guaifenesin is available in both prescription and nonprescription products. Check the labels on all your medications carefully to make sure you are not taking more than one product that contains guaifenesin.

The risk of serious side effects (such as slow/shallow breathing, severe drowsiness/dizziness) may be increased if this medication is taken with other products that may also cause drowsiness or breathing problems. Tell your doctor or pharmacist if you are taking other products such as other opioid pain or cough relievers (such as morphine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

Other medications can affect the removal of guaifenesin/codeine from your body, which may affect how guaifenesin/codeine works. Examples include azole antifungals (such as ketoconazole), bupropion, fluoxetine, macrolide antibiotics (such as erythromycin), HIV medications (such as ritonavir), paroxetine, quinidine, rifamycins (such as rifabutin, rifampin), certain drugs used to treat seizures (such as carbamazepine, phenytoin), among others.

This medication may interfere with certain laboratory tests (e.g., urine 5-HIAA levels, urine VMA levels, amylase/lipase levels), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: fast/slow/irregular heartbeat, slow/shallow breathing, cold/clammy skin, coma.

If you are prescribed this medication on a regular schedule and miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Do not share this medication with others. Sharing it is against the law.

This medication has been prescribed for your current condition only. Do not use it later for another condition unless told to do so by your doctor. A different medication may be necessary in that case.