Adults and children 12 and older can take Allegra once or twice a day, depending on the strength. The standard options are one 180 mg tablet once daily or one 60 mg tablet every 12 hours. Both schedules deliver the same total amount and work equally well for seasonal allergies and chronic hives.
Standard Dosing for Adults
Allegra (fexofenadine) comes in two main tablet strengths for adults: 180 mg and 60 mg. If you’re taking the 180 mg tablet, you take it once every 24 hours. If you’re taking the 60 mg tablet, you take one every 12 hours, for a maximum of two tablets (120 mg total) in 24 hours. Don’t double up or take extra doses if your symptoms feel stubborn. The dosing schedule is the same whether you’re treating hay fever or chronic hives.
Dosing for Children
Children ages 2 to 11 take a lower dose: 30 mg every 12 hours, typically as a liquid suspension. That means no more than two doses (60 mg total) in a 24-hour period. Children under 2 should not take over-the-counter Allegra without specific guidance from a pediatrician.
For kids 12 and older, the dosing matches the adult schedule.
How Long Each Dose Lasts
Allegra starts working within about one hour of your first dose. It reaches its peak effect at two to three hours and continues providing meaningful symptom relief for a full 12 hours. The drug’s half-life in the body is roughly 14.4 hours, which is why a single 180 mg dose can cover an entire day while a 60 mg dose needs to be repeated at the 12-hour mark.
If you take the once-daily 180 mg version, try to take it at the same time each day. If you’re on the twice-daily 60 mg version, spacing your doses 12 hours apart keeps a steady level in your system and avoids gaps in relief.
What If You Have Kidney Problems
Your kidneys are responsible for clearing fexofenadine from your body. If you have reduced kidney function, the drug stays in your system longer, so the recommended starting dose drops to 60 mg once daily for adults (or 30 mg once daily for children 6 to 11). This is half the typical frequency. If your kidney function is impaired and you’re unsure whether to adjust your dose, your pharmacist or doctor can help you figure out the right schedule.
Fruit Juice Reduces Absorption
Allegra has an unusual interaction that most people don’t expect: grapefruit, orange, and apple juice all reduce how much of the drug your body absorbs. This doesn’t make it dangerous, but it can make a dose less effective, essentially as though you took a smaller amount. The FDA labels for Allegra specifically warn against taking it with fruit juices. Swallow your dose with water instead, and avoid drinking large amounts of these juices within a couple of hours of your dose.
What Happens If You Take Too Much
Allegra has a wide safety margin compared to older antihistamines. In clinical studies, doses well above the recommended amount did not cause serious toxicity. That said, sticking to the labeled maximum of 180 mg per day (or 60 mg twice daily) is the safest approach. Taking an extra tablet by accident on a single occasion is unlikely to cause harm, but routinely exceeding the dose won’t improve your symptoms and puts unnecessary strain on your kidneys over time.
Unlike first-generation antihistamines such as diphenhydramine (Benadryl), Allegra does not cause significant drowsiness at recommended doses, which is one reason people feel tempted to take more when symptoms persist. If your current dose isn’t controlling your allergies, a different medication or combination approach is a better solution than increasing the amount of Allegra you take.