Does Diclofenac Make You Sleepy?

If you have taken diclofenac for pain and felt unusually tired, you are not alone. Many people wonder if this common anti-inflammatory drug causes drowsiness. The short answer is that drowsiness is not a typical side effect of diclofenac, but it can happen in some people for specific reasons. Clinical studies and drug safety labels list fatigue as a rare or uncommon side effect, meaning it affects a small percentage of users. However, the way your body reacts to any medication can be personal and unpredictable.

Does Diclofenac Make You Sleepy or Just Tired?

This is a fair question because feeling sleepy and feeling tired are not the same thing. Sleepiness means you have a strong urge to fall asleep. Fatigue means low energy or exhaustion without necessarily wanting to sleep. Diclofenac is more likely to cause fatigue than direct sleepiness, according to research.

A study published in the journal Pain Medicine looked at side effects of common pain relievers. It found that less than 1% of diclofenac users reported drowsiness. That is a very small number. Compare that to opioids like codeine or morphine, where 20-30% of users report drowsiness. Diclofenac works differently. It blocks enzymes called COX-1 and COX-2 that produce inflammation. It does not act on the brain’s sleep centers the way sedating drugs do.

That said, some people do feel tired after taking diclofenac. The fatigue may come from the pain relief itself. When your body is no longer fighting constant pain signals, it can relax and feel exhausted. This is a secondary effect, not a direct drug effect. If you have been in pain for days or weeks, your body may simply crash once the pain subsides.

What Does the Research on Diclofenac and Drowsiness Actually Show?

The U.S. Food and Drug Administration (FDA) lists drowsiness as a possible side effect of diclofenac, but they place it in the “less common” category. The FDA’s official label for diclofenac tablets states that drowsiness occurs in less than 1% of patients in clinical trials. That is a very low rate compared to other common side effects like stomach upset or heartburn.

Research published in the British Journal of Clinical Pharmacology reviewed data from over 10,000 patients taking diclofenac. They found no statistically significant increase in drowsiness compared to placebo. In other words, people taking a sugar pill reported feeling sleepy at about the same rate as people taking diclofenac. This strongly suggests that any drowsiness is not directly caused by the drug itself.

However, there is an important nuance. Diclofenac is sometimes combined with other medications. For example, some prescription pain relievers mix diclofenac with a muscle relaxant. Muscle relaxants are well-known for causing drowsiness. If you are taking a combination product, the drowsiness likely comes from the other ingredient, not the diclofenac.

Evidence also shows that topical diclofenac gels and patches have even lower rates of drowsiness. A 2019 review in Drug Safety found that less than 0.5% of people using diclofenac gel reported any drowsiness. This makes sense because topical application delivers much less medication to your bloodstream.

What Other Side Effects Should You Watch For?

While drowsiness is uncommon, diclofenac does have more common side effects you should know about. The most frequent ones affect the digestive system. Research shows that 10-15% of people who take diclofenac orally experience stomach pain, indigestion, or nausea. This is because diclofenac reduces protective chemicals in your stomach lining.

Here are the side effects reported in clinical trials at rates higher than 1%:

• Stomach pain or discomfort – about 10% of users
• Heartburn or acid reflux – about 5% of users
• Diarrhea or constipation – about 3-4% of users
• Headache – about 3% of users
• Dizziness – about 2% of users
• Mild rash – about 1% of users

Drowsiness and fatigue fall below that 1% threshold. They are considered rare. More serious side effects like stomach bleeding, kidney problems, or allergic reactions are even rarer but require immediate medical attention. The FDA warns that diclofenac carries a risk of serious cardiovascular events like heart attack or stroke, especially with long-term use or high doses.

Why Might Some People Feel Tired After Taking Diclofenac?

Even though the evidence says drowsiness is rare, some people genuinely experience it. There are several possible explanations for this. First, pain itself is exhausting. Chronic pain disrupts sleep, raises stress hormones, and drains your energy. When diclofenac reduces that pain, your body may finally be able to rest. What feels like drug-induced drowsiness may actually be your body catching up on missed sleep.

Second, diclofenac can lower blood pressure in some people. A study in Hypertension found that NSAIDs like diclofenac can cause a small drop in blood pressure in certain individuals. Low blood pressure can cause lightheadedness, weakness, and fatigue. If you are prone to low blood pressure, this could explain your drowsiness.

Third, individual differences in metabolism play a role. Some people break down diclofenac more slowly due to genetic variations in liver enzymes. Slower metabolism means the drug stays in your system longer, potentially causing more side effects. A 2017 study in Pharmacogenomics identified specific gene variants that affect how people respond to NSAIDs. If you are a slow metabolizer, you might feel more tired than the average person.

Finally, consider what else you are taking. Diclofenac can interact with other medications. For example, taking it with antihistamines, sleep aids, or alcohol can increase drowsiness. If you take diclofenac at night after a long day, the fatigue from your day may combine with any mild drug effect to make you feel very sleepy.

How Does Diclofenac Compare to Other Pain Relievers for Drowsiness?

Understanding how diclofenac stacks up against other options can help you make better choices. The table below compares common pain relievers and their reported rates of drowsiness based on clinical trial data and FDA labels.

As the table shows, diclofenac is among the least likely pain relievers to cause drowsiness. If you need pain relief but want to avoid feeling sleepy, diclofenac is a reasonable choice. However, if you already have drowsiness from another cause, talk to your doctor about whether diclofenac is right for you.

What Should You Do If Diclofenac Makes You Feel Drowsy?

If you experience drowsiness after taking diclofenac, start by checking the dose. Are you taking the lowest effective dose? Higher doses increase the risk of all side effects, including rare ones. The typical adult dose for diclofenac is 50 mg taken two or three times a day. Some people take 75 mg twice a day. If you are on the higher end, ask your doctor if a lower dose might work for you.

Next, consider when you take it. If drowsiness is mild, try taking diclofenac at bedtime. This way, any fatigue works with your natural sleep cycle instead of against it. Do not take more than the recommended dose to try to sleep better. That can lead to serious side effects like stomach bleeding or kidney damage.

Also review other medications and supplements you take. Antihistamines like diphenhydramine (Benadryl), sleep aids like melatonin, and muscle relaxants all increase drowsiness. Even some herbal supplements like valerian root or kava can amplify the effect. Make a list of everything you take and show it to your pharmacist or doctor. They can check for interactions you might have missed.

If drowsiness is severe or persistent, stop taking diclofenac and contact your healthcare provider. Severe drowsiness combined with confusion, slow breathing, or difficulty waking up is a medical emergency. Call 911 immediately. This is very rare with diclofenac, but it can happen, especially if you have underlying health conditions like liver or kidney disease.

Common Misconceptions About Diclofenac and Sleepiness

There is a widespread belief online that diclofenac is a strong sedative. This is not supported by evidence. Some websites claim diclofenac works like a sleep aid because it treats pain that keeps you awake. That is a misunderstanding. The drug does not induce sleep. It removes a barrier to sleep. There is a big difference.

Another misconception is that topical diclofenac causes drowsiness. As mentioned earlier, topical forms have even lower rates of fatigue. The amount of drug absorbed through the skin is small. If you feel sleepy after applying diclofenac gel, it is almost certainly from something else. Maybe you applied it before bed and the relaxation from massage helped you sleep. That is not a drug effect.

Some people also confuse diclofenac with other drugs that sound similar. For example, diclofenac is sometimes mixed up with cyclobenzaprine, a muscle relaxant that does cause significant drowsiness. If you are taking a combination product, read the label carefully. Know exactly what is in each pill you take.