Opioid Pain Reliever Side Effects

Constipation

Having less frequent or more difficult bowel movements than usual may commonly occur if opioids are taken for more than a few days. All opioids slow down natural muscle movements in the bowels (intestines and colon). The resulting "irregularity" or constipation may continue for as long as opioids are taken, but it is more of a problem in some persons than others — and it can be effectively managed.

Drinking plenty of fluids, some exercise (if possible and safe), and a diet rich in natural fiber (grains, fruits, vegetables) may be of help. You also should talk to your opioid prescriber or pharmacist about medicines called "stool softeners" and "stimulant laxatives." Some of these are available without prescription.

DO NOT take products called "bulk-producing laxatives" (such as, Metamucil, FiberCon, Citrucel, or others) as these are unhelpful for constipation due to opioids and may even make the constipation worse.

Nausea

This is a sensation of discomfort in the upper stomach with an urge to vomit ("throw up"). Any nausea due to opioids usually goes away within a few days. If this continues, or if you have vomiting and cannot keep down the opioid medicine, call your opioid prescriber. There is medicine that can help with nausea. Also, try sitting calmly and breathing through your mouth. Drinking small amounts of ginger ale helps some persons to combat nausea, as does sips of ginger, chamomile, or peppermint tea.

Sedation

Mild feelings of being drowsy, sleepy, "light-headed," or "cloudy-headed" can be common when first starting opioids or after a dose increase. Some persons experience these feelings much more than others. It can take days or weeks for this to completely go away. Until any sedation goes away, you will need to avoid activities that may be dangerous if you are not fully alert, such as driving a car or operating machinery (including power tools and lawn mowers at home).

If sedation continues to be a problem there are medicines that can be prescribed to help. If you cannot stay awake and are repeatedly nodding off to sleep this may be a more serious indication of opioid overmedication — stay awake and call your opioid prescriber right away.

Itching, Dry Skin

Itchy, dry skin can be bothersome if it occurs, but it is usually temporary and is not the same as being allergic to opioids. If you develop a rash and/or hives along with the itching it could be an allergic reaction and you should stop taking the medicine and call your opioid prescriber about this right away.

Confusion

When first starting opioid therapy some, but not all, persons find it more difficult to concentrate and think clearly. Some persons may have difficulty remembering things for awhile. Similar to the more common sedation, this may last from several days to a week or two. If confusion continues, or gets worse, talk to your opioid prescriber about it as soon as possible.

Muscle Twitching

Opioids may sometimes cause uncontrollable muscle twitching, jerking, or shaking - usually of the arms or legs - that can be bothersome. It is not harmful but, in some cases, may make pain worse due to the quick movements. Usually, the twitches are mild and do not happen very often. If this is an ongoing problem, your opioid prescriber may reduce the opioid dose or switch you to a different opioid, and there also are certain medicines that can be prescribed to ease this condition.

Hormonal Disturbances

Taking opioids for a long time and/or at higher doses may decrease normal levels of certain hormones in the body. Hormones are chemicals that regulate organ function, body growth, and tissue repair. The hormone disturbances due to opioids may reduce sexual desire and performance in men and women. They also may influence weight gain and depression ("feeling blue"), weaken bones, and cause menstrual period irregularities. Certain medicines may help to control or reduce the problems, but it also may be necessary to decrease the opioid dose, switch to a different opioid or, eventually, discontinue taking opioids. A simple blood test can be done to measure hormone levels. Each person is different and, if hormonal problems occur, you will need to work closely with your opioid prescriber in finding the best solution.

Others

When starting opioid therapy, some persons are bothered by dry mouth, sweating, fatigue or weakness, or mild headaches. Almost always, these are temporary problems and will go away as your body gets used to the opioid medicine. Your opioid prescriber or pharmacist can prescribe or recommend medicines to help ease these effects.

Allergic Reaction

Few people have a true allergy to opioids. However, if after starting an opioid medicine you develop a rash, hives, swelling (of lips, tongue, hands, or other body part), or tightening in the throat stop taking the medicine and seek medical attention right away.

Urine Retention

Having difficulty passing urine (peeing) when starting opioid therapy is uncommon, but happens more often in elderly men. It usually goes away fairly quickly, but it may be necessary to insert a tube into the bladder to temporarily allow the flow of urine (this is called "catheterization"). Call your opioid prescriber right away if this problem occurs — do not delay.

Heart Problems

There have been rare reports of certain opioids upsetting normal heartbeat, a condition called "arrhythmia." Call your opioid prescriber right away if your heart is sometimes pounding, or if it is beating either oddly, rapidly, or extremely slowly; also call if you are feeling faint or actually have a fainting spell. This is especially important if you are taking methadone or using the buprenorphine patch.

Increased Pain Sensitivity

In some persons opioids help greatly in reducing pain at first but, after awhile, taking opioids may seem to actually make the pain worse. This is not the same as opioid tolerance (this is, getting used to the usual dose and needing more opioid). Increasing the opioid dose does not help, and the reasons for this condition - called "hyperalgesia" - are not completely understood. Fortunately, it happens in few persons taking opioids. It may be necessary to reduce the opioid dose, switch to another opioid, or discontinue taking opioids at least for a period of time. In some cases, pain may normally increase because of opioid tolerance, or due to increased physical activity, or from worsening of a condition causing the pain. Talk to your opioid prescriber if the pain worsens at any time while taking opioids.

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