July 2010




Oral acetaminophen as an analgesic

by Vanessa Caceres EyeWorld Contributing Editor


Study finds simple pain relief

A recent study found oral acetaminophen helpful for reducing pain during and after cataract surgery Source: Bartlomiej J. Kaluzny, M.D.

A common oral medication may be the key to reducing patients’ pain during cataract surgery. A study published in the March issue of the Journal of Cataract & Refractive Surgery found that patients who received oral acetaminophen before surgery reported lower scores on a pain intensity scale and on a verbal rating scale.

In Europe, intravenous acetaminophen is growing in popularity to alleviate intraoperative and post-op pain, but this can be expensive. “When it first came to mind that oral acetaminophen could be used to improve patients’ comfort during phacoemulsification, I was surprised to find that no one had ever verified this idea before,” said lead study investigator Bartlomiej J. Kaluzny, M.D., department of ophthalmology, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Poland.

Study details

To prove how effective oral acetaminophen (paracetamol) could be, Dr. Kaluzny and co-investigators completed their study between October 2007 and January 2008 in 160 consecutive phacoemulsification patients, with 80 patients in each group. Patients who participated were having surgery for uncomplicated age-related cataract, were between the ages of 50 and 90, and had visual acuity in the contralateral eye that was sufficient for use of a visual analog scale. Investigators eliminated patients who had other ocular disease or health problems that could influence pain sensitivity, such as diabetes or neurological disorders.

Patients in one group received two acetaminophen tablets (500 mg/tablet), while patients in the second group received a placebo (two vitamin C tablets). Neither the patients nor the nurses and eye surgeons knew which kind of medication was given.

Patients received midazolam 3.75 mg one hour before surgery along with the placebo or acetaminophen. Surgeons also instilled the eye three times with unpreserved tetracaine 0.5%; patients who were particularly anxious received fentanyl intravenously.

Standard phacoemulsification through a 2.2-mm clear corneal incision was performed with the divide-and-conquer or phaco-chop technique, followed by insertion of a foldable acrylic IOL.

Right after surgery, surgeons noted if any intra-operative problems occurred and used a 5-point scale to track the demeanor of the patient during surgery—the scale ranged from 0 for very calm to 4 for very anxious.

Additionally, at 15 minutes post-op, patients scored their surgery pain intensity with a 10-cm baseline visual analog scale and a verbal rating scale that went from no pain (a score of 0), mild pain (1), moderate pain (2), severe pain (3), to the worst possible pain (4).

Tracking results—and implications

Investigators found some differences between the acetaminophen and placebo groups. The mean intra-operative visual analog scale pain intensity score in the placebo group was 2.17 versus 1.45 in the acetaminophen group. The mean verbal rating score was 1.11 in the placebo group and 0.67 in the acetaminophen group. After surgery, the mean visual analog scale pain score was 1.47 in the placebo group and 0.56 in the acetaminophen group; the mean verbal rating was 0.94 and 0.28, respectively. Investigators reported no significant difference in patient behavior during surgery—the mean surgeon-reported score was 1.04 in the placebo group versus 0.77 in the acetaminophen group, a difference that investigators said is not statistically significant. No significant adverse effects from the use of acetaminophen were reported. A statistically significant number of patients received fentanyl for anxiety in the placebo group versus the acetaminophen group—11 versus 6 patients.

The use of oral acetaminophen could cut down on the use of intravenous acetaminophen, which is effective but more expensive, Dr. Kaluzny said. He added that previous studies have shown that oral acetaminophen preparations are slow to absorb and unpredictable in their effectiveness. However, he believes that this study bucks the results from past research.

“The conclusions of the study are very practical. A cataract surgeon can start to use oral acetaminophen [right] away and improve patients’ comfort during and after surgery without an increase in procedure cost,” Dr. Kaluzny said.

Other surgeons said they would like to use oral acetaminophen in their patients based on this article’s results.

“With patients in the U.S. paying more out of pocket for premium IOL technologies, they expect a higher quality experience,” said Y. Ralph Chu, M.D., Edina, Minn. “For most patients, this would equate with not just great visual outcomes but also a very comfortable procedure and surgical process.” Another potential benefit is that acetaminophen is known to have fewer gastrointestinal (GI) side effects and a lower risk of GI bleeding than other nonsteroidal anti-inflammatory drugs, Dr. Chu said.

Although J.E. “Jay” McDonald II, M.D., Fayetteville, Ark., finds most of today’s cataract patients do not need pain relief, he said that those who use oral acetaminophen in the first 24 hours post-op for pain and scratchiness say it relieves their pain. “Since employing clear corneal sutureless surgery, pain has been such a small issue that we may have ignored the fact that prophylactic giving of acetaminophen makes great sense in trying to make our cataract surgery convenient, painless, and effective,” Dr. McDonald said. “I still sense that fear of pain is one of the key issues that causes people to avoid cataract surgery.” He is considering adding oral acetaminophen usage to his patients’ pre-op routine.

Editors’ note: The physicians interviewed have no financial interests related to their comments.

Contact information

Chu: 952-835-0965, yrchu@chuvision.com
Kaluzny: bartka@by.onet.pl
McDonald: 479-521-2555, mcdonaldje@mcdonaldeye.com

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