Painkillers are only recommended in addition to active treatments such as exercises and movement – for example, to relieve severe back pain or to help you start moving more again. Because of the associated risks, though, they shouldn't be used over a long period of time.
Low back pain usually goes away on its own after a while. In most cases it's not clear what's causing the pain. It is then called "non-specific" back pain. If low back pain lasts a long time or keeps returning, it is often difficult to treat. Good-quality studies have so far found that only few treatments help. Staying active and moving enough are among the most effective things you can do yourself.
The medications used include over-the-counter and prescription painkillers, muscle relaxants and antidepressants. Because medication can have side effects – especially when taken over longer periods of time – it shouldn't be taken continuously, but rather only for a short while, for example when the pain is especially severe. What's more, painkillers only have a limited effect in the treatment of non-specific low back pain.
Over-the-counter painkillers
Non-steroidal anti-inflammatory drugs (NSAIDS) such as diclofenac, ibuprofen and naproxen are the most commonly used medications for low back pain. They can often relieve the symptoms a little. Lower doses of these drugs are available without a prescription. NSAIDs can be taken as tablets or injected into muscle tissue. Injections aren't recommended nowadays, though, because they can cause bleeding or inflammation where the needle enters the skin. In rare cases they can also lead to serious complications such as abscesses or nerve damage.
NSAIDs can cause stomach ache and – if taken over long periods of time – increase the likelihood of developing a stomach ulcer. They also slightly increase the risk of developing certain heart problems. People who have kidney failure should talk to their doctor before taking NSAIDs. Because of the possible side effects, it's a good idea to carefully consider the pros and cons of the medications, make sure you don't take them for too long, and use them correctly.
Two other anti-inflammatory painkillers that have a similar effect are two COX-2 inhibitors called celecoxib and etoricoxib (also referred to as coxibs). These medications are not approved for the treatment of back pain, so they are only rarely used – for instance, if opioids are the only other option.
Acetaminophen (paracetamol)
The painkiller acetaminophen (paracetamol) is also sometimes used to treat low back pain. But studies have shown that it is no more effective than a placebo (fake medication).
When using this painkiller, it's important to make sure you take the right dose. An overdose of acetaminophen can damage the liver and also cause liver failure. So experts recommend not taking more than 4 grams (4,000 mg) per day. This is the amount in, for example, 8 tablets containing 500 milligrams each. When taken at the right dose, though, acetaminophen is well tolerated. It is not suitable for people with liver problems.
Metamizole ("Novalgin")
Metamizole is a fever-reducing and anti-inflammatory painkiller that is similar to the NSAIDs. Although it is often used for the treatment of low back pain, there are no studies on its effectiveness in this area. Medical societies consider it to be an alternative to opioids for severe low back pain.
The use of metamizole is controversial because it can have a rare but very serious side effect called agranulocytosis, where the number of certain types of white blood cells decreases so much that it can become life-threatening. Possible signs of agranulocytosis include fever, a sore throat and inflamed mucous membranes. But the risk of this side effect is estimated to be much less than 0.1%. Metamizole is prescription-only in Germany.
Opioids
If other treatments don't work well enough, low back pain can be treated with stronger, prescription-only painkillers known as opioids. The best-known opioid is morphine. Other opioids include buprenorphine, codeine, hydromorphone, oxycodone, tapentadol, tilidine and tramadol. Opioids vary in their strength. Morphine, for example, is a very strong opioid, while tramadol is a weaker one. They are also available as skin patches.
Opioids are very effective at relieving many different types of acute pain. But they aren't as good at relieving low back pain as commonly believed. In studies, opioids were shown to relieve the pain in only about 10 out of 100 people. They usually don't work any better than NSAIDs do.
Opioids can have side effects such as constipation, nausea, decreased sex drive, dizziness and tiredness, affecting your ability to drive vehicles. There is also a small risk of a life-threatening overdose. So it is very important to follow the doctor's instructions and not to increase the dose without talking to the doctor first. This is also true for skin patches containing opioids (e.g. fentanyl patches). People can become physically dependent on opioids too. According to studies in this area, it is estimated that this happens to about 6% of all people who use opioids over a long period of time.
Treatment with opioids is an option if other treatments haven't helped enough or if NSAIDs can't be used. Opioids generally shouldn't be used for longer than 12 weeks. If you use opioids, it can be a good idea to seek advice from a pain specialist who has a lot of experience with these drugs.
Muscle relaxants
Muscle relaxants are thought to relieve pain by reducing tension in the muscles. They are usually prescription-only sedatives that influence the central nervous system.
Muscle relaxants can relieve acute back pain in the short term. But they haven't been proven to help relieve chronic low back pain.
Muscle relaxants can have side effects like drowsiness or dizziness. This can affect your ability to drive, and also increase the risk of falls in older people. Taking these medications can be a problem for people who operate machinery, too. Muscle relaxants known as benzodiazepines can be addictive as well.
Due to these side effects, medical societies in Germany do not recommend using muscle relaxants for the treatment of back pain.
Antidepressants
Antidepressants are prescription-only drugs used to treat depression. Some of these medications have also been approved for the treatment of chronic pain. Most antidepressants haven't been proven to help in chronic low back pain. One exception is the drug duloxetine, which can relieve the symptoms a little.
Antidepressants have a number of side effects, including loss of appetite, nausea, a dry mouth and low blood pressure. They can reduce sexual desire too. Medical societies in Germany do not recommend using antidepressants for the treatment of back pain.
Treatment with injections
If other treatments don't help relieve low back pain, treatment with injections is often offered. This involves injecting various pain-relieving or numbing medications, including the following:
Local anesthetics
Steroids
Botulinum toxin (Botox)
Some of these medications aim to stimulate the body’s natural healing processes if the problem is being caused by irritated nerve roots, tendons and ligaments, or to reduce inflammation or numb the pain. Different drugs are injected into different places: for instance, into muscle tissue, into the tissue directly surrounding nerves, ligaments or spinal disks, into the joints of the spine, or into a space in the spinal canal known as the epidural space.
There is no good-quality research on the effectiveness of the various kinds of injections in the treatment of non-specific low back pain. Although side effects are rare, they can lead to serious complications. For example, if an anesthetic is injected into the wrong place it can cause respiratory paralysis, making it hard to breathe. Injections near the spine can also lead to infections.
Because it's not clear how effective they are and because of the possible risks, it's not a good idea for people with non-specific low back pain to have treatment with injections. Medical societies in Germany do not recommend injections for this purpose.