Can you take Allegra and ibuprofen together?

Why

Fexofenadine and ibuprofen do not interact with each other. Allegra Allergy 24 Hour is a single-ingredient product — its Drug Facts list "Fexofenadine HCl 180 mg", an antihistamine that blocks H1 receptors and barely crosses into the brain, which is why it is the non-drowsy option. Advil's Drug Facts list "Ibuprofen 200 mg (NSAID)" as a "Pain reliever/Fever reducer", working by blocking prostaglandin production. No shared ingredient, no shared elimination route, and no additive sedation the way there would be with an older antihistamine. Neither label names the other as a drug to avoid. This page says caution rather than a flat yes for three reasons: what else may be in the box, what the antacid you take for NSAID stomach upset does to fexofenadine, and kidneys. Start with absorption, because it is the part of the Allegra label people trip over in exactly this situation. Under "When using this product" it says "do not take at the same time as aluminum or magnesium antacids" and "do not take with fruit juices". Fexofenadine depends on uptake transporters in the gut wall to reach the bloodstream and binds metal cations; the failure mode is not toxicity, it is that your allergy pill quietly does less. That matters here because someone taking ibuprofen for pain often adds an antacid to settle their stomach. MedlinePlus gives the fix: "if you are taking an antacid containing aluminum or magnesium (Maalox®, Mylanta®, others), take the antacid a few hours before or after fexofenadine." It repeats the juice rule too: "Do not take with fruit juices such as orange, grapefruit, or apple juice." Do not go by brand name — turn the bottle over and look for the words aluminum or magnesium in the Active Ingredients panel, because antacids marketed on their calcium carbonate content frequently contain magnesium hydroxide as well. Water is what the Allegra Directions specify. Kidney disease is the one condition both labels name, and it is where these two genuinely converge. Allegra Allergy 24 Hour says "Ask a doctor before use if you have kidney disease. Your doctor should determine if you need a different dose", and its Directions repeat "consumers with kidney disease ask a doctor". NSAIDs including ibuprofen can reduce kidney function — so the drug you are adding for pain moves you toward the state in which your allergy drug needs a dose decision from a clinician. The Advil label also carries a warning that applies regardless of what you pair it with: "NSAIDs, except aspirin, increase the risk of heart attack, heart failure, and stroke. These can be fatal." Now the boxes, because neither brand name means one formula. Advil Dual Action with Acetaminophen is acetaminophen 250 mg plus ibuprofen 125 mg per caplet — the only Advil that contains a second pain drug. Its "Do not use" section says "with any other drug containing acetaminophen (prescription or nonprescription)", and its liver warning reads: "Severe liver damage may occur if you take: with other drugs containing acetaminophen; more than 6 caplets in 24 hours, which is the maximum daily amount for this product; 3 or more alcoholic drinks every day while using this product". The realistic version of this accident is an allergy-and-cold day: Allegra, "an Advil" for the aches, and a cold-and-flu powder or a Tylenol on top. Advil Cold and Sinus is "Ibuprofen 200 mg (NSAID)" plus "Pseudoephedrine HCl 30 mg". Advil PM is "Ibuprofen 200 mg (NSAID)" plus "Diphenhydramine citrate 38 mg" — labeled a "Nighttime sleep-aid", it is a sedating antihistamine stacked on the non-drowsy one you deliberately chose. On the other side, Allegra-D 12HR is "Fexofenadine HCl 60 mg" plus "Pseudoephedrine HCl 120 mg" and Allegra-D 24 Hour is "Fexofenadine HCl 180 mg" plus "Pseudoephedrine HCl 240 mg" — two different products with two different decongestant strengths. Both Allegra-D labels add ask-a-doctor conditions plain Allegra does not have (heart disease, thyroid disease, glaucoma, high blood pressure, diabetes, trouble urinating due to an enlarged prostate gland), plus kidney disease, which plain Allegra names as well. Both are taken on an empty stomach, which pulls against the habit of taking ibuprofen with food. Combining an Allegra-D with an Advil Cold and Sinus is not merely two decongestants: pseudoephedrine raises blood pressure and heart rate while the NSAID carries its own heart attack, heart failure and stroke warning, so in anyone with hypertension that stack pushes from both directions at once.