Pain relieving meds are very useful for doctors and patients. But, like other drugs, they have side effects, some of which are unknown. You can buy most painkillers in a store without a prescription or “over the counter.” As the name suggests, these medications are taken for mild pain and fevers. If the pain persists, then you need something stronger than painkillers. The common over the counter pain meds include acetaminophen, aspirin, ibuprofen, and naproxen. Also, there is a powerful type of painkiller that should be prescribed before taking it called opioids. This type is given to people who have had recent surgery, painful injury or living with a serious long-term condition like cancer. Below, we are going to look at some unknown side effects of painkillers in the body.

Causes Brain Damage

Whether a painkiller is prescribed or acquired from a store, it can cause serious changes to the brain and body of the user. The effects can occur with short term use, but most dangerous brain damage happens due to long term use. A painkiller is meant to block the brain’s perception of pain by binding to opiate receptors, therefore, interfering with signals transmitted by the central nervous system to the brain decreasing the feeling of pain while increasing a feeling of relaxation.

Long term use of painkillers slows down the production of natural chemicals by the body making it less effective in relieving pain naturally. Meaning the painkillers replaces the neurotransmitters although they can’t fill all the neurotransmitters role. Neurotransmitters are necessary to send signals between nerves to complete brain and body connections. Additionally, painkillers depress the central nervous system, which is the brain and nerves, thus it leads to slower breathing, slurred speech, and slower bodily reactions.

Allergic Reactions

This is a rare side effect which most people don’t know about. Even though it happens in one out of six patients taking painkillers, it can be serious at times. In case you are taking painkillers and you experience an allergic reaction; you need to talk to your doctor. Here are some of the symptoms you need to look out for:

  • A rash
  • Shortness of breath
  • Redness or swelling of the face
  • Feeling hot
  • A sudden need to pass urine
  • Dizziness

Causes Kidney Disease

Heavy or long-term use of some painkillers like ibuprofen, naproxen and high doses of aspirin can lead to a kidney disease called chronic interstitial nephritis. There is always a warning label on over the counter drugs telling you not to use these medicines for more than 10 days for the pain and more than three days for fever. If you have decreased kidney function, high doses of painkillers, especially aspirin, aren’t recommended. Note that regular consumption of painkillers doesn’t increase the risk of kidney disease in people with normal kidney function. But, taking doses that are too large, more than six to eight tablets a day, can temporarily or permanently reduce kidney function. For people with kidney disease, aspirin can increase the tendency to bleed.

Causes High Blood Pressure

Researchers have found painkillers to cause high blood pressure or make it worse for people who have it. As a result, your chances of heart attack or a stroke increases too. In fact, painkiller prevents some blood pressure drugs from working right. These drugs include:

  • Diuretics, or water pills, such as Hydrodiuril which helps remove excess water from the blood vessels.
  • ACE inhibitors like Prinivil and Zestril used to relax the blood vessels.
  • ARBs such as Cozaar also used to relax the blood vessels.

Low Hormone Levels

Painkillers can lead to low levels of testosterone or estrogen (the male and female hormones respectively). Consequently, one may have erectile dysfunction, reduced libido, fatigue, hot flashes, menstrual irregularities, weight gain, and depression. The hormonal imbalance can further lead to serious complications such as infertility and osteoporosis.

Dry Mouth

Dry mouth is a state whereby the salivary glands don’t make enough saliva to keep the mouth wet. Taking certain medications including over the counter drugs can cause dry mouth. Pain medications cause symptoms such as:

  • Thick saliva
  • Dryness and feeling of stickiness in your mouth
  • Bad breath
  • Dry or sore throat and hoarseness
  • A changed sense of taste


Managing the side effects of pain medications can be done effectively. Some side effects of painkillers could be symptoms of other conditions like cancer, thus the interdisciplinary approach to symptoms management is important. Despite the well-known dangers of painkillers, the number of deaths from painkillers has quadrupled to nearly 15,000 per year in the U.S. You should be careful when taking painkillers and in case of any side effects, you need to talk to your doctor immediately.

All images by Pixabay


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