Can You Take a Muscle Relaxer and Naproxen Together?

Taking a muscle relaxer and naproxen together is generally safe, and doctors prescribe the combination routinely for conditions like acute low back pain with muscle spasm. The two drugs work through different mechanisms and do not interact in ways that create dangerous pharmacological conflicts. That said, the evidence on whether the combination actually works better than naproxen alone is surprisingly mixed, and the choice of muscle relaxer matters more than most people realize.

What the Clinical Evidence Actually Shows

The logic behind combining naproxen with a muscle relaxer seems intuitive: naproxen handles inflammation and pain, the muscle relaxer addresses spasm, and together they should outperform either drug alone. Some research supports this. A randomized trial comparing the combination of cyclobenzaprine and naproxen against naproxen alone found that patients receiving both drugs had less muscle spasm, less tenderness, and greater range of motion in the lower spine. There were also trends toward faster pain relief and quicker return of function with the combination.¹

But a larger and more rigorous trial, published in JAMA, reached the opposite conclusion. In that study, patients with acute low back pain who came to an emergency department were given naproxen plus either cyclobenzaprine, an opioid combination, or placebo. Adding cyclobenzaprine to naproxen did not improve functional outcomes or pain at the one-week follow-up compared to naproxen with placebo.² A separate trial tested naproxen with two different muscle relaxers, orphenadrine and methocarbamol, against naproxen alone. Again, neither combination crossed the threshold for a clinically meaningful improvement.³

A broader systematic review and meta-analysis in the BMJ looked at muscle relaxants for non-specific low back pain across many trials. It found that the class of muscle relaxants most commonly paired with NSAIDs like naproxen (non-benzodiazepine antispasmodics) was associated with a modest reduction in pain intensity at two weeks, but not a meaningful reduction in disability.⁴ The pain-reducing effect was real but small, and the certainty of the evidence was rated very low.

So the honest picture is mixed. The combination is safe to take, and some patients clearly benefit. But the average improvement from adding a muscle relaxer on top of naproxen is modest, and several well-designed trials have found no added benefit at all. This does not mean the combination is useless for you specifically. It means the blanket assumption that two drugs must work better than one does not hold up as cleanly as you might expect.

Why Doctors Still Prescribe the Combination

If the evidence is lukewarm, why is this pairing so common? Partly because clinical guidelines endorse both drug classes for the same condition. The American College of Physicians recommends NSAIDs or skeletal muscle relaxants as first-line pharmacologic options for acute low back pain.⁵ A global comparison of thirteen clinical practice guidelines found that nearly all recommended NSAIDs, and about half also recommended muscle relaxants for the same condition.⁶

When a patient has clear muscle spasm on top of inflammatory pain, prescribers often reach for both classes simultaneously. The guidelines treat NSAIDs and muscle relaxants as separate tools in the same toolkit rather than a fixed combination, but nothing in the guidelines warns against using both. In practice, the decision often comes down to how much spasm a patient has, how much the pain is interfering with sleep (since many muscle relaxers are sedating), and how the patient responded to either drug alone in the past.

The Muscle Relaxer You Choose Matters

Muscle relaxers are not interchangeable. Different drugs in this class have meaningfully different side effect profiles, interaction characteristics, and even different ways they pair with naproxen.

Cyclobenzaprine is the most commonly prescribed muscle relaxer in the United States and the one most studied alongside naproxen. The main drawback is drowsiness. In the trial that found benefits from the combination, the increased side effects were driven almost entirely by drowsiness from cyclobenzaprine.¹ A driving simulation study found that cyclobenzaprine significantly impaired lateral control of a vehicle compared to placebo, and most subjects who performed poorly did not even feel unsafe to drive.⁷ That disconnect between perceived safety and actual impairment is worth knowing if you plan to drive while taking both drugs.

Tizanidine stands out because it has an unusual secondary benefit when paired with NSAIDs. Animal research and pharmacological studies show that low doses of tizanidine improve gastrointestinal tolerability of naproxen by roughly half, while simultaneously enhancing its pain-relieving and anti-inflammatory effects.⁸ A review of tizanidine’s pharmacology described this gastroprotective property as one of its additional clinical advantages, noting it can improve patient tolerance to NSAIDs.⁹ Since stomach irritation is one of the most common complaints with naproxen, tizanidine’s pairing with it is interesting from a practical standpoint. Tizanidine does cause drowsiness and can lower blood pressure, so it is not without tradeoffs.

Methocarbamol and orphenadrine are older muscle relaxers that are generally well tolerated but showed no meaningful benefit over placebo when added to naproxen in clinical trials.³ They are considered relatively mild but also relatively limited in how much they add.

Carisoprodol deserves a separate caution, covered below.

The Stomach Problem With Naproxen

When people worry about combining these drugs, the interaction between them often gets the spotlight. But the bigger day-to-day risk for most people is naproxen’s effect on the stomach, whether or not a muscle relaxer is involved. NSAIDs as a class are known to cause gastrointestinal problems by reducing protective prostaglandins in the stomach lining. This can lead to mucosal injury, ulceration, and in serious cases, GI bleeding.¹⁰

How common is this? NSAIDs produce symptoms of dyspepsia in up to half of users, and peptic ulcer disease develops in up to about one in five people taking them. The risk climbs with age over 70, a personal history of ulcers, use of multiple anti-inflammatory agents at once, higher NSAID doses, and concurrent use of corticosteroids or blood thinners.¹¹ Adding a muscle relaxer does not directly increase the stomach risk, but if you are already at elevated risk from naproxen, the sedation from a muscle relaxer can mask early warning symptoms by making you less alert to discomfort.

Beyond the gut, NSAIDs can raise blood pressure, contribute to cardiovascular events, and impair kidney function.¹² A meta-analysis specifically looking at blood pressure found that NSAIDs have hypertensive effects that are often underappreciated compared to their well-known GI risks.¹³ These risks belong to naproxen regardless of what you combine it with, but they are worth understanding any time you are taking it for more than a day or two. The general medical advice is to keep NSAID use at the lowest effective dose for the shortest possible duration.¹²

Sedation, Driving, and Compounding Effects

The most noticeable side effect of combining these drugs is increased drowsiness. Naproxen on its own is not particularly sedating, but most muscle relaxers are. When the two are taken together, the sedative effect of the muscle relaxer remains the dominant concern. The BMJ meta-analysis found that non-benzodiazepine muscle relaxants roughly doubled the risk of experiencing an adverse event compared to controls, with sedation being the most common complaint.⁴

The driving impairment issue is more serious than most patients realize. In a controlled study, cyclobenzaprine caused significant impairment in lane-keeping and other measures of driving ability. The concerning finding was that only about one in ten subjects who received cyclobenzaprine felt unsafe to drive on the first day, dropping to about one in thirty by the second day, even though their actual performance remained impaired.⁷ If you are taking a muscle relaxer with naproxen for back pain and planning to go about your normal routine, be aware that you may feel fine to drive while actually being impaired. Taking the muscle relaxer dose at bedtime and using naproxen during the day is a common workaround that many prescribers suggest.

Alcohol amplifies the sedation from muscle relaxers considerably. If you are taking both naproxen and a muscle relaxer, adding even moderate amounts of alcohol can push drowsiness into a range that affects coordination and judgment. This is a standard warning on the label of virtually every muscle relaxer, but it is particularly relevant when someone is already on a multi-drug regimen.

The Carisoprodol Exception

Among the muscle relaxers that might be combined with naproxen, carisoprodol (sold as Soma) carries unique risks that set it apart from the rest of the class. Carisoprodol is metabolized in the body into meprobamate, a substance with abuse potential on par with benzodiazepines. Reports have documented carisoprodol being misused for its sedative effects, used to augment the effects of other drugs, and combined with other medications specifically because it is easier to obtain than controlled substances.¹⁴ Several U.S. states have classified it as a controlled substance, and some European countries have imposed restrictions on its use.

A retrospective review of prescription data found that long-term carisoprodol users, compared to users of other muscle relaxers, used opioids more frequently alongside the drug and used NSAIDs less frequently. They also had more past diagnoses related to drug dependence or abuse and continued paying out of pocket for carisoprodol when insurance coverage was cut off.¹⁵ None of those patterns alone proves misuse, but together they paint a picture. If your doctor prescribes carisoprodol alongside naproxen, it is not inherently dangerous as a short-term combination, but the drug carries dependency risk that cyclobenzaprine, methocarbamol, or tizanidine simply do not.

Older Adults Face Higher Stakes

The combination of a muscle relaxer and naproxen becomes riskier with age. On the muscle relaxer side, several of the most commonly prescribed options, including carisoprodol, cyclobenzaprine, metaxalone, methocarbamol, and orphenadrine, are flagged as drugs to avoid in older adults due to the risk of excessive sedation and falls.¹⁶ The Beers Criteria, a widely used reference for medications in older patients, lists many of these agents as potentially inappropriate.

On the naproxen side, age over 70 is itself a risk factor for NSAID-related gastric injury.¹¹ Kidney function tends to decline with age, and NSAIDs can worsen that trajectory. When both drug classes carry elevated risks in the same population, the combination demands closer supervision. For older adults with back pain, prescribers often lean toward non-drug approaches first and reserve medications for when they are truly needed, keeping courses as short as possible.

Non-Drug Options Worth Knowing About

The American College of Physicians guideline actually recommends trying non-drug treatments before reaching for any medication, noting that most episodes of acute low back pain improve on their own regardless of treatment. Superficial heat had moderate-quality evidence behind it, while massage, acupuncture, and spinal manipulation had lower-quality but still supportive evidence.⁵ The guideline positions NSAIDs and muscle relaxants as options if you want medication, not as the first step.

This framing matters when you are considering whether to combine two drugs. If the underlying question is “should I take both?” rather than “can I take both?”, the evidence suggests starting with naproxen alone, possibly alongside a heating pad or gentle movement, and adding a muscle relaxer only if spasm or sleep disruption is a distinct problem that naproxen is not addressing. The global guideline comparison supports this approach: staying active, exercise, and heat therapy are recommended by the majority of guidelines, with muscle relaxants as one of several pharmacologic add-ons rather than a first-line default.⁶

How Tizanidine Protects the Stomach

One of the more interesting wrinkles in this topic is that not all muscle relaxers merely add side effects when combined with naproxen. Tizanidine appears to actively counteract one of naproxen’s biggest drawbacks. Pharmacological studies have shown that low-dose tizanidine works synergistically with naproxen, producing enhanced anti-inflammatory and pain-relieving effects while simultaneously cutting GI side effects by about half.⁸ The mechanism is thought to involve tizanidine’s alpha-2 adrenergic activity, which reduces gastric acid secretion and provides a gastroprotective effect that NSAIDs on their own strip away.

This does not mean tizanidine is a free lunch. It can cause drowsiness, dry mouth, dizziness, and drops in blood pressure. It also has known interactions with certain antibiotics (like ciprofloxacin) and the antidepressant fluvoxamine, which can dramatically increase tizanidine levels in the blood. But from a purely stomach-related standpoint, the tizanidine-naproxen pairing is more favorable than, say, cyclobenzaprine-naproxen, where the muscle relaxer adds nothing to offset naproxen’s GI effects and simply piles on drowsiness.

This kind of drug-specific pairing detail rarely comes up in a standard doctor’s appointment. If you have a sensitive stomach and your prescriber is choosing between muscle relaxers to add to naproxen, raising the question of tizanidine is reasonable, though the final decision depends on your full medication list and medical history.