Ketorolac is a powerful prescription NSAID with a long list of drugs and substances that can cause serious problems when combined with it. The FDA limits ketorolac to a maximum of 5 days of use because the risk of dangerous side effects rises sharply beyond that window. Within that short treatment period, what you take alongside it matters just as much as how long you take it.
Other Pain Relievers and NSAIDs
The single most important rule with ketorolac: do not take it with other NSAIDs. That includes ibuprofen (Advil, Motrin), naproxen (Aleve), and aspirin. Combining two NSAIDs doesn’t double the pain relief, but it does stack the risk of stomach ulcers, intestinal bleeding, and perforation (a hole forming in the stomach or intestinal wall). The FDA’s labeling for ketorolac explicitly lists concurrent use of aspirin or any other NSAID as contraindicated, meaning it should never happen.
This catches people off guard because ibuprofen and aspirin feel like mild, everyday medications. But ketorolac is already one of the strongest NSAIDs available. Adding another one on top pushes the cumulative risk of gastrointestinal damage into dangerous territory.
Blood Thinners
Ketorolac inhibits platelet function on its own, which means it already slows your blood’s ability to clot. Pairing it with anticoagulants like warfarin or direct oral anticoagulants, or with antiplatelet drugs like clopidogrel, significantly raises the chance of uncontrolled bleeding. The FDA labeling contraindicates ketorolac in anyone with incomplete hemostasis, hemorrhagic conditions, or a high bleeding risk. If you’re on any medication prescribed to prevent blood clots, your doctor needs to know before ketorolac enters the picture.
Blood Pressure Medications and Diuretics
A combination that doctors call the “triple whammy” involves an NSAID like ketorolac, a blood pressure drug that targets the renin-angiotensin system (such as ACE inhibitors like lisinopril or ARBs like losartan), and a diuretic (water pill). Each drug individually affects how your kidneys regulate blood flow and fluid balance. Together, they can cause acute kidney injury.
Here’s why: ACE inhibitors and ARBs relax the blood vessels leaving your kidneys, which lowers the pressure that drives filtration. Diuretics reduce your overall fluid volume, cutting blood flow to the kidneys further. Then ketorolac blocks the production of prostaglandins, which are chemicals your kidneys rely on to keep the incoming blood vessels open. With all three pathways disrupted at once, your kidneys can’t maintain adequate filtration. A study reviewing emergency department visits between 2007 and 2018 confirmed that this triple combination was a recurring cause of drug-induced kidney injury requiring hospitalization.
Even without the diuretic, ketorolac can reduce the effectiveness of ACE inhibitors and ARBs by blocking the same prostaglandin pathways those drugs depend on. So your blood pressure medication may simply stop working as well.
Corticosteroids
Taking ketorolac alongside oral steroids like prednisone or dexamethasone dramatically increases the risk of upper gastrointestinal complications. Research comparing users of both drug types to people taking neither found the risk of serious GI events (ulcers, bleeding, perforation) was roughly 8.5 times higher in people taking both an NSAID and an oral steroid simultaneously. Both drug classes irritate the stomach lining through different mechanisms, and the combined effect is far worse than either one alone.
SSRIs and SNRIs
If you take an antidepressant in the SSRI class (such as fluoxetine, sertraline, or escitalopram), combining it with ketorolac raises your risk of upper gastrointestinal bleeding substantially. SSRIs reduce serotonin levels in platelets, which impairs clotting. Ketorolac independently impairs clotting and damages the stomach lining. One analysis found the risk of upper GI bleeding was nearly 11 times higher in people taking both an SSRI and an NSAID compared to people taking neither. Even more conservative estimates put the combined risk at about four times higher than baseline. This interaction is often overlooked because antidepressants aren’t typically thought of as bleeding risks.
Lithium and Methotrexate
Ketorolac can push lithium levels in your blood dangerously high. It does this by reducing how efficiently your kidneys clear lithium, causing the drug to accumulate. Lithium has a narrow therapeutic window, meaning the difference between a helpful dose and a toxic one is small. Symptoms of lithium toxicity include tremors, confusion, vomiting, and in severe cases, seizures or kidney failure.
A similar mechanism affects methotrexate, a drug used for autoimmune conditions and certain cancers. Ketorolac slows the kidneys’ ability to eliminate methotrexate, allowing it to build up to toxic concentrations. If you take either of these medications, your prescriber should be aware before you receive ketorolac.
Probenecid and Pentoxifylline
Two less commonly discussed but formally contraindicated combinations: probenecid (used for gout) and pentoxifylline (used for circulation problems). Probenecid slows the body’s clearance of ketorolac, effectively increasing how much of the drug stays in your system and for how long. Pentoxifylline has its own blood-thinning properties, and combining it with ketorolac raises bleeding risk. The FDA labels both of these as absolute contraindications, not just cautions.
Alcohol
Alcohol irritates the stomach lining independently, and ketorolac does the same through prostaglandin inhibition. Drinking while on ketorolac compounds the risk of stomach bleeding and ulceration. Given that ketorolac is only used for 5 days maximum, avoiding alcohol during that short window is a straightforward way to reduce your risk of a serious GI event.
The 5-Day Limit
Regardless of what you do or don’t combine with it, ketorolac itself has a hard ceiling: 5 days total across all forms (injection, oral tablets, nasal spray), whether used alone or sequentially. The frequency and severity of adverse effects rise with each additional day. This isn’t a soft guideline. It’s an FDA-mandated maximum because the risks of GI bleeding, kidney damage, and cardiovascular events climb steeply beyond that point. If you’re still in pain after 5 days, your doctor will need to transition you to a different approach.