The influence of analgesic medication on physiologic processes and exercise


Analgesic medication is a category of drug that is meant to cause the cessation of pain within an individual. Because of the effect that analgesics have on the body, these types of medication are more commonly referred to as painkillers. They come in both prescription form and over-the-counter form and are typically used by individuals who have experienced some type of injury or who suffer from painful diseases. This type of medication is normally the first step in acute injuries and minor pains.
As with all medication, there are positives and negatives associated with the usage of analgesic medications. The level of class in which a analgesic medication falls determines whether it is available via prescription from a physician or for purchase over the counter at local drug stores. The effects of these medications range from insignificant to deadly depending on the class of medication administered. 

Effects on Activities of Daily Living (ADLs)  

One study set out to determine the effects of opioid usage on activities of daily living (ADL). The medication used in the study was the buprenorphine transdermal delivery system (BTSD), and this medication was evaluated for its effectiveness in helping patients with chronic low back pain (CLBP) perform ADLs. The results showed that those individuals with CLBP who wore the BTSD patch experienced a reduction in pain and a significant improvement in abilities to carry out ADLs [1]. The BTSD could benefit those who wish to implement a strengthening or stretching regime because it ultimately reduces pain and allows increased participation in ADLs.

Effects on Athletes 

Athletes often take analgesic drugs to relieve soreness after exercise. An uncommon positive side effect that can go along with using analgesic medication is increased time to exhaustion during exercise in the heat. The article by Mauger, A.R., Taylor, L., Harding, C., Wright, B., Foster, J., & Castle, P.C. (2014) discusses how acute acetaminophen (paracetamol) ingestion improves time to exhaustion during exercise in the heat. Experimental physiology 99(1). p. 164-171, states that acute acetaminophen ingestion lead to significantly increased time to exhaustion when exercising in hot conditions. The authors hypothesized that this could occur because acetaminophen possibly decreases the thermoregulatory challenge that occurs when exercising in the heat. This can be useful information when working with athletes who have to compete in hot weather conditions.

Common analgesic drugs that can be found over-the-counter and are taken post-exercise are ibuprofen and acetaminophen. Although these drugs have been suggested to relieve muscle soreness after exercise, they may have negative physiological effects as well. Typically, after exercise, muscle protein synthesis increases, leading to hypertrophy of the involved muscles. In a study done by Trappe, White, Lambert, Cesar, Hellerstein, and Evans (2002), subjects who had consumed ibuprofen and acetaminophen post-exercise actually experienced weakened protein synthesis. These results suggest that long-term use of analgesic medications such as ibuprofen and acetaminophen may actually decrease the typical hypertrophy that follows eccentric training[2]. Therefore, if an athlete is trying to build muscle, he or she may not benefit from consistently taking analgesic drugs.

Effects on Renal System 

Another important and less known physiological effect of analgesic medication on the body is that on the kidneys. Farquhar, Morgan, Zambraski, and Kenney (1999) suggested that it is safer to consume acetaminophen than ibuprofen because it has less severe renal effects. In individuals who had recently exercised, ibuprofen was more likely to decline renal function[3]. These findings suggest that it may not be safe to consume certain analgesic drugs during exercise to maintain the function of the kidneys so that an individual may avoid dehydration during exercise.

According to Farquhar, Morgan, Zambraski, and Kenney (1999) acetaminophen and ibuprofen not only stress the kidneys and renal function during exercise, but taking such drugs can inhibit proper recovery following the completetion of physical activity also. In athletes the production of urine was below the initial baseline level for up to ninety minutes following exercise, [4].

Additional Precautions

Although analgesic medications effects can relieve muscle soreness, another less known danger is the risk of addiction from opioids and other over-the-counter medications. According to a fact sheet from the Oklahoma government and the Centers for Disease Control and Prevention, deaths from opioid pain relievers have now surpassed deaths from cocaine and heroin [5]. Oklahoma ranks 9th in overdose rates in the United States and according to the 2009 National Survey on Drug Use and Health, Oklahoma ranks first in every age category for the consumption of non-medical pain relievers. This statistic is noteworthy in the physical therapy professions. Many patients are post-operatively prescribed over-the-counter drugs, as well as generic analgesics like acetaminophen and ibuprofen. Apart from their exercise side effects, addictions to these drugs can bring cognitive impairment, psychomotor impairment and serious withdrawal symptoms with the end of long term prescriptions [6]. Cognitive impairment can bring dangerous side effects to exercise during therapy. It can increase the risk for falls or further injury, while withdrawal symptoms can include serious illnesses that make physical therapy difficult, if not impossible for such a patient. [7]
This chart shows how death rates from opioid usage in America have increased over time.


  1. Miller K, Yarlas A, Wen W, Dain B, Lynch SY, Ripa SR, et al. The impact of buprenorphine transdermal delivery system on activities of daily living among patients with chronic low back pain: an application of the international classification of functioning, disability and health. Clin J Pain. 2014 Dec;30(12):1015-22.
  2. Trappe T, White F, Lambert C, Cesar D, Hellerstein M, Evans W. Effect of ibuprofen and acetaminophen on postexercise muscle protein synthesis. American Journal of Physiology 2002;282:551-6. (accessed 10 November 2015).
  3. Farquhar W, Morgan A, Zambraski E, Kenney W. Effects of acetaminophen and ibuprofen on renal function in the stressed kidney. Journal of Applied Physiology 1999;86:598-604. (accessed 10 November 2015).
  4. Farquhar W, Morgan A, Zambraski E, Kenney W. Effects of acetaminophen and ibuprofen on renal function in the stressed kidney. Journal of Applied Physiology 1999;86:598-604. (accessed 10 November 2015).
  6. Zacny, J. P. A review of the effects of opioids on psychomotor and cognitive functioning in humans. Experimental and Clinical Psychopharmacology 1995; 3(4), 432..
  7. Lewis, T. (2015, November). The government is keeping track of these commonly prescribed drugs to help fight a major epidemic. Retrieved from