Common Risks and Side Effects of Treating Breakthrough Pain

No medication is without risk, but the potency of medications for breakthrough pain makes it especially important to follow usage directions carefully.

Medications should never be increased without the doctor’s approval, and the doctor must be informed of all other medications, including vitamins and supplements, being taken.

See Medications for Back Pain and Neck Pain

These are some potential dangers:

  • Life-threatening overdoses. Abuse of a narcotic medication, accidentally using too much of a prescribed drug, or accidentally ingesting medication can all cause overdoses. Narcotic overdoses killed 28,000 people in 2014.9

    Even a minuscule amount of fentanyl can be fatal if not taken as directed. Fentanyl has also caused fatal reactions in those who are allergic to, or have no experience with, narcotic medications. These medications must not be accessible to others. It is also illegal to share these narcotics with anyone else.

    Extra care is needed when using one formulation of a drug on a schedule, and another form for breakthrough pain. These medications are not interchangeable, and must be used only as prescribed to avoid an overdose. Using a bright-colored marker to distinguish one container from the other may help prevent a dangerous mixup when a patient is tired or distracted.

  • See Narcotic Pain Medications

  • Tolerance to medication. Tolerance occurs over a long period, as the body becomes accustomed to a narcotic medication and more is needed to have the same effect the medication had at the start.10
  • Dependence on medication. Dependence is body’s physiological adaptation, and need for, a medication to function normally. It comes after tolerance has occurred, and happens when the medication either is not increased or is unavailable. Withdrawal symptoms such as sweating, insomnia, and anxiety may result.11,12 If a patient wants to quit taking prescribed narcotics, talking with the doctor first is recommended. The doctor can provide a schedule for tapering off the medication gradually. There is some debate about the terms dependence and addiction, and the terminology used by medical professionals and others varies.
  • Addiction to medication. When someone is addicted to a medication, attaining the medication takes priority over family, work, and other responsibilities and relationships. Brain changes that develop gradually can reduce self-control and lead to a compulsive need for the medication.13
  • See Pain Killer Addiction Treatment

  • Respiratory problems. The way narcotic medications work in the body can have the side effect of suppressing normal breathing. Respiratory depression is more common in people using narcotics whose bodies have not yet become accustomed to this type of medication. The fastest-acting narcotics, including fentanyl, pose the highest risk. People who have not built up a tolerance for narcotics are at risk of respiratory depression and death from taking any amount of fentanyl. It is for this reason that immediate-release fentanyl is not designed for those who have not been using strong narcotic medications regularly for at least a week.
  • Respiratory risks are magnified when alcohol is used or medications with a sedating effect, such as sleep aids and antidepressants, are taken. The sedating effect can extend to the respiratory system, with dangerous results.

  • Bothersome physical reactions. Frequent side effects include nausea, constipation, dizziness, sleepiness, and physical dependence. Notifying the doctor about any bothersome side effects is advised.

Due to concerns about overuse of narcotics, patients may need to work more closely with the doctor than in the past to receive a new prescription or refill. Some states also require narcotic use to be tracked. Checking with the doctor about the prescription process well in advance is advised.

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Special Considerations for Fentanyl

Due to fentanyl’s potency (the U.S. Drug Enforcement Administration considers it 50 to 100 times stronger than morphine),8 it is crucial to follow directions on dosages, schedules, and medication disposal precisely.

Other factors to be aware of with fentanyl include:

  • Sugar in lozenges. Each fentanyl lozenge has about 2 grams of sugar, equivalent to half a teaspoon, which may be an issue for people with diabetes and could lead to tooth decay.14
  • Laxatives in suckers. Some forms of the lollipop-shaped medication include a laxative that acts quickly in some people.

This is not a complete list of precautions. Talking over any medication concerns with the doctor or pharmacist is advised.

See Opioid Medication Potential Risks and Complications for more


  1. Opioids: The Prescription Drug & Heroin Overdose Epidemic. U.S. Department of Health and Human Services.
  2. The Neurobiology of Drug Addiction: Definition of tolerance. National Institute on Drug Abuse. January 2007. Available at
  3. The Neurobiology of Drug Addiction: Definition of dependence. National Institute on Drug Abuse.

Complete Listing of References