Results of a new study provide information on the trajectories of prescription drug use before and after total hip arthroplasty (THA). The study was published online ahead of print November 14 in Pain.
Researchers merged Norwegian national joint replacement and prescription databases to analyze the medication use of nearly 40,000 patients undergoing THA from 2005 to 2011. The patients’ average age was 68.5 and about three-fourths of patients underwent THA because of primary osteoarthritis.
The investigators analyzed trends in prescription drug use over 2 years: 4 quarters before and 4 quarters after hip-replacement surgery. The study focused on analgesics and hypnotics as well as drugs to treat anxiety and depression.
Overall, about half of patients filled a prescription for an analgesic in the year before surgery. Analgesic use included nonsteroidal anti-inflammatory drugs (NSAIDs) in 38% of patients, opioids in 16%, and other non-opioid analgesics in 12%.
Use of pain medications continued to increase during the last quarter before THA and then increased dramatically in the first quarter after surgery. The sharpest increases were for opioids, which increased to 28% in the last quarter before THA, then to 65% in the first quarter afterward; non-opioid analgesics increased to 21% and then to 60.5%.
The percentage of patients who filled prescriptions for hypnotics also increased from the quarter before to the quarter after surgery—from 14% to 25%. Analysis of the dosage showed a similar pattern.
With continued follow-up after THA, medication use decreased. By 1 year after THA, opioid use had decreased to 14%, NSAID use had decreased to 18%, and non-opioid analgesic use had decreased to 13%. Use of hypnotic drugs also decreased, along with medications to treat anxiety. There was little or no change in the use of antidepressants.
“Patients with chronic pain are frequent users of analgesic and psychotropic drugs and thereby risk adverse drug events,” said Tone Blågestad, a PhD candidate from the Department of Clinical Psychology at the University of Bergen in Norway, and coauthors. They cited special concern about the potential for serious adverse effects of opioids, including drug overdose.
Tone Blågestad
The results suggest that use of pain medications increases in the year before THA, with a further increase immediately afterward, followed by a long-term decrease. That pattern is consistent with previous studies on pain scores in the period before and after THA.
Hypnotic drug use shows a similar trend, suggesting that sleep problems get worse, then improve with long-term pain relief after THA. The lack of change in antidepressant use suggests that depression in patients undergoing hip replacement isn’t necessarily related to hip pain.
“Overall, the present results extend the positive effects of THA to include reduced reliance on medication to alleviate symptoms,” said Ms. Blågestad and colleagues. The finding that hypnotics follow the same prescription trajectory as analgesics highlights the link between pain and sleep. The researchers add, “Our results warrant attention to the increased risk of adverse medication effects occurring with the increased use of both opioids and hypnotics in the recovery phase.”