Codeine relieves mild to moderate pain, and is frequently used along with other drugs such as acetaminophen or aspirin to increase its effectiveness against pain. It also helps control cough, and is sometimes combined with other medicines to treat the symptoms of respiratory infections.

• If you are allergic to anything, including medicines, dyes, additives, or foods.

• If you have any medical conditions such as kidney disease, liver disease (including hepatitis), low thyroid function, or Addison's disease (low adrenal function). These conditions may require that your medicine dose, regimen, or timing be changed.

• If you have trouble urinating, a narrow urethra, or if you have an enlarged prostate. Codeine can make it harder to urinate.

• If you have ever had a seizure, head injury, or if you have had problems with pressure, infection, or a tumor in your head or brain. Codeine can raise your risk of seizures.

• If you have low blood pressure. Codeine can worsen this.

• If you have asthma, emphysema, chronic bronchitis, sleep apnea, or other breathing problems. Codeine can make them worse.

• If you have had abdominal pain, pancreatitis, or any disorder involving slowed or blocked intestines, such as paralytic ileus. Morphine can worsen this problem.

• If you are allergic to sulfites. Some codeine combinations contain sulfites.

• If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. There may be an increased risk of harm to the fetus if a woman takes this drug during pregnancy, especially later in pregnancy.

• If you are breast-feeding. The drug passes into breast milk and can affect the baby.

• About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

• anti-anxiety drugs (tranquilizers or sedatives)
• sleeping pills
• muscle relaxers
• barbiturates
• anti-seizure medicines
• other opioid drugs such as morphine
• anesthetics
• antidepressants such as amitriptyline, desipramine, doxepin, imipramine, nortriptyline
• anti-psychotic drugs
• certain anti-nausea medicines
• alcohol

Some of these drugs can cause slowed breathing, low blood pressure, extreme sleepiness, coma, or even death if taken with codeine.

Antidepressants of the older MAO inhibitor type such as phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan), or selegiline (Emsam) may cause coma, slow or shallow breathing, low blood pressure, excitability, seizures, or shock if codeine is given within 2 weeks of the last MAO inhibitor dose.

Certain drugs for allergies, bowel spasms, overactive bladder, Parkinson's disease, muscle spasms, and breathing problems can raise the risk of bowel blockage and trouble passing urine if taken with codeine. Antidepressants in the tricylic family, such as amitriptyline, desipramine, doxepin, imipramine, nortriptyline can do the same thing.

Newer antidepressants such as fluoxetine (Prozac), paroxetine (Paxil) and Duloxetine (Cymbalta) may affect your response to codeine. Anti-seizure drugs, TB drugs, quinidine (heart rhythm drug), and St. John's wort may also change codeine's effects. Your doctor may want to watch you more closely if you are taking these drugs while on codeine.

Buprenorphine (Subutex, Suboxone), butorphanol (Stadol), nalbuphine (Nubain), or pentazocine (Talwin, Talacen) may decrease the effects of codeine or stop its action altogether. This can cause serious withdrawal very quickly if you have taken the codeine for some time.

Check with your doctor, nurse, or pharmacist about whether other medicines, vitamins, herbs, and supplements can cause problems with this medicine.

Take this drug exactly as directed by your doctor. If you do not understand the instructions, ask your doctor or nurse to explain them to you.

Keep it in a tightly closed container away from heat and moisture and out of the reach of children, pets, and others. Do not allow other people to take your medicine. Flush unused codeine down the toilet as soon as possible.

People who are allergic to sulfites or aspirin should check with their pharmacist to find out if their codeine pills contain sulfites or aspirin.

This medicine can cause drowsiness and lightheadedness. Do not drive, operate machinery, or perform other activities that require alertness until you know how you react to this medicine.

Codeine can make you feel dizzy or faint, and increase your risk of falling. Be careful getting up, changing position, or walking. Start slowly and hold onto something or someone to keep you steady. If you feel lightheaded or dizzy, it may help to lie down. It is best to have a responsible adult with you for the first few days after starting the codeine and after any increase in dose, until you know how you will respond to it.

Since codeine affects the central nervous system, do not take other drugs or substances that slow down the brain or nervous system such as alcohol, sedatives, muscle relaxers, and sleeping medicines unless your doctor tells you to do so.

Call your doctor right away if you have trouble breathing, get short of breath, get confused, feel very drowsy, or start seeing or hearing things that aren't there. These may be signs your dose is too high, or you could have gotten an accidental overdose of the medicine.

Talk to your doctor or nurse about using the smallest effective dose to reduce side effects and the development of tolerance and physical dependence. Tolerance means that larger doses are needed to get the same pain relief. Physical dependence means that the body goes into withdrawal if drug is suddenly stopped. Both happen normally when strong (opioid) medicines are taken over several weeks to treat chronic pain. But this is different from addiction, which starts when the drug is taken for pleasure rather than pain relief. Tell your doctor or nurse if you still have pain even though you are taking the medicine as directed. Do not adjust your dose without talking to your doctor or nurse.

If you have chronic cancer pain, talk to your doctor or nurse about taking your pain medicines on a regular schedule to keep it from worsening. If you wait until the pain is bad, it takes more medicine to get it under control. If pain comes back between doses, talk to your cancer team about changing your medicine or adding an extra one for "breakthrough" pain.

Most cancer pain can be controlled. Keep your doctor or nurse informed about how well your pain medicines are working and any side effects you are having. Your cancer team may need to adjust your medicines several times before they find the medicines that work best for you.

Constipation is a very common side effect of taking opioid pain medicines. While you're taking codeine, you should take take medicines such as stool softeners, bulk-forming agents, and/or laxatives as needed to have regular (daily) bowel movements. Talk to your nurse or doctor about this when you first start this medicine. Drink plenty of fluids throughout the day, and try to eat foods high in fiber such as whole grains, bran, fruits, and vegetables. Call your doctor or nurse right away if you have not moved your bowels in 2 days.

If you have an allergic reaction, with symptoms like trouble breathing, itchy welts on your skin, or swelling in your mouth or throat, get emergency help right away.

Call your doctor or nurse right away if you have trouble passing your urine, trouble walking, vision problems, fainting, trouble swallowing, or other problems.

If you are having any kind of surgery or medical procedure, be sure to tell the doctor or dentist in charge that you are using this medicine.

Do not stop taking this medicine without talking to your doctor or nurse. If it is stopped too quickly or the dose reduced too much, you can have withdrawal symptoms. When no longer needed, this drug should be stopped gradually with the help of your doctor.

This drug is a controlled substance, and may be habit forming. Do not allow others to take your medicine. A person who has taken codeine for some time often needs large doses for pain relief, while the same amount could quickly kill someone else.

If you think you or someone else may have taken an overdose of codeine, get emergency help right away. Symptoms of codeine overdose may include extreme drowsiness, slow heart beat, slow or irregular breathing, cold clammy skin, or coma. Codeine overdose may cause the heart or breathing to stop. Contact the pharmacy to learn what other drugs are in the pill with the codeine, since an overdose could have delayed effects (if it contains acetaminophen, for example), and need special treatments.

• drowsiness*
• sedation*
• mood changes, including happiness, irritability, agitation, depression
• dizziness or lightheadedness*
• constipation*
• dry mouth

• mental clouding, confusion*
• nausea
• vomiting
• low blood pressure, which can cause dizziness when sitting or standing up*
• flushing
• itching
• sweating
• decreased heart rate
• difficulty urinating
• trouble breathing*
• abdominal pain*

• seizures
• tiny pupils in eyes
• slow breathing*
• ruptured bowel from constipation
• decreased sexual ability
• decreased sexual interest
• withdrawal symptoms if dose is reduced too quickly after taking it a few weeks*
• allergic reaction with shortness of breath, itching skin welts, dizziness, or swelling in mouth or throat*

*See "Precautions" section for more detailed information.