Your body behaves differently at different times of the day, notes Richard Martin, MD, head of the pulmonary division at National Jewish Medical and Research Center in Denver.
These so-called circadian rhythms affect allergy and asthma, too.
Martin says hay fever symptoms -- such as weepy eyes, runny nose, and sneezing -- peak in the morning hours. So taking your 24-hour allergy medications before going to bed means that you'll get the maximum effect when you need it the most.
"Taking your allergy medication at night assures that it will be circulating in your blood stream when you most need it, early the next morning," Martin says in a news release.
People with less severe asthma use steroid inhalers. These drugs have their greatest effect when taken between 3:00 p.m. and 5:30 p.m., Martin says.
Is This Really Necessary?
Martin's schedule would maximize allergy and asthma drug effects only if people really take their medication every day, says William E. Berger, MBA. Berger is professor of medicine at the University of California, Irvine, and past president of the American Academy of Allergy, Asthma & Immunology. He's also the author of Allergies and Asthma for Dummies.
"It is unrealistic to think that people who have to take preventive medicines on a regular basis, such as inhaled steroids, will take them between 3:00 and 5:30 in the afternoon," Berger tells WebMD. "The vast majority will take them when -- and if -- they remember to take them."
What worries Berger and other allergists is that preventive medicines have to be taken when a patient is feeling fine -- before symptoms occur. And if the medication is working, patients who usually feel great have to remember to take their daily dose.
"It is a great accomplishment to get patients to take medicines when there aren't any symptoms," Berger says. "The concern here is that when you tell busy people to take their medication at an inconvenient time, they might not take the dose at all."
Berger and Martin both stress that consistent use of allergy medications is the key to successful symptom prevention. Both recommend tying taking the drugs to other things done every day at the same time.
"A lot of us in clinical practice tell patients to associate taking their medications with something they always do," Berger says. "So I often tell them, "When you brush your teeth at night, take your meds."
So what about trying to get the most from allergy medications by taking them at the best time of day?
"If you can do that, great, it certainly is optimal," Berger says. "But in the real world, it may not be optimal, but it is certainly appropriate for busy people to take their daily allergy medications whenever they can regularly do so."
Before making any changes to your drug schedule, please check with your health care provider.