Hong Zhengxian, deputy teaching team leader of the Department of Pharmacy, Akirahama Shuden, said that the painkillers posted do not mean that there are no systemic side effects. Non-steroidal anti-inflammatory painkillers, whether taken orally or externally, may affect renal blood flow.
When you have sore shoulders, neck, or back pain, you can easily apply a piece of external analgesic patch, but careless use may cause harm to the body. Hong Zhengxian, deputy teaching team leader of the Department of Pharmacy, Akirahama Shuden, shared that a 44-year-old man in Japan used an anti-inflammatory and analgesic patch after falling down while riding a bicycle and was injured. His kidney function deteriorated significantly in less than a month, and he was even hospitalized. He reminded that the analgesics posted do not mean that there are no systemic side effects, nor does it mean that they will not be absorbed by the body. Especially the five groups of people with poor kidney function and the elderly should pay more attention to their use.
Hong Zhengxian posted on his Facebook page that the Japanese man was originally in generally good health. He fractured his left thigh after falling while riding a bicycle and underwent surgery to fix it. Later, he was found to have osteoporosis. After the bone nail was removed, treatment with active vitamin D and commercially available calcium tablets was started. Later, he suffered a sprained neck due to a car accident. He initially took anti-inflammatory painkillers orally, and after taking them three times, he switched to pain-relieving patches, which he used twice a day.
Unexpectedly, in less than a month, the man's kidney function deteriorated rapidly, with his creatinine rising to 5.16mg/dL and his blood calcium rising from 8.9 mg/dL to 12.0 mg/dL. Although he had no obvious symptoms of fever, rash or infection, he still had to be hospitalized. After discontinuing medications and supplements that may be related to kidney damage, and undergoing biopsy, he developed acute interstitial nephritis and acute tubular injury. After ruling out other causes, the medical team believed that the pain relief patch may be one of the important factors causing acute kidney injury. Fortunately, after stopping the drug and receiving treatment, the kidney function gradually improved.
In this regard, Hong Zhengxian explained that the painkiller patch does not mean that there are no systemic side effects. The painkiller patch used by the man is a non-steroidal anti-inflammatory analgesic. Such drugs, whether taken orally or externally, may affect kidney blood flow. Generally speaking, the amount of topical preparations entering the systemic circulation is smaller, so the risk is usually lower. However, if you have poor kidney function, are older, are dehydrated, are taking other drugs that may affect kidney function, or are using analgesic patches in large quantities and for a long time, you need to be more careful.
Hong Zhengxian warned that this is a single clinical case and does not mean that applying painkiller cloth will definitely damage the kidneys. It is still a safe and effective choice for most people when used in an appropriate amount and for a short period of time according to the instructions of a doctor or pharmacist. What really needs to be noted is that "external use" does not mean "not absorbed by the body at all." Especially those with chronic kidney disease, high blood calcium, or those taking multiple drugs at the same time should inform their doctor or pharmacist before long-term use.
