RELATED: If You Do This Common Thing With Your Pills, Have Your Liver Checked Now. If you regularly take an antihistamine to treat allergies, you may run into a problem if there’s an occasion when you also feel the need to prepare for motion sickness. Experts say the two medications can cause sudden, extreme drowsiness, which can be a dangerous proposition if you’re on the road.ae0fcc31ae342fd3a1346ebb1f342fcb Prevention reports that the problem arises because the two medications can cause moderate drowsiness when taken individually. Taken together, you’re doubling down on some of their stronger active ingredients. “Use caution when combining antihistamine allergy meds like Benadryl with nausea-busting treatments like Dramamine. Their similar active ingredients—diphenhydramine to treat sniffles, red eyes, and sneezing, and dimenhydrinate to ease motion sickness—can add up to excess drowsiness,” their experts write. This could pose a particular problem if you take these medications on an ill-timed schedule while traveling. “I’ve heard about people sleeping through their flight connection because they took too much antihistamine,” Nicole Gattas, PharmD, an associate professor of pharmacy practice at St. Louis College of Pharmacy told the magazine. RELATED: If You’re Over 60, Do Not Take This OTC Medication Every Day, Officials Say. The good news is that if you already take antihistamines, they may effectively treat your motion sickness with no additional medication required, says the Cleveland Clinic. “Commonly used to treat allergies, antihistamines can also prevent motion sickness and ease symptoms,” the organization’s experts say. “Only antihistamines that cause drowsiness are effective. Non-drowsy formulas won’t help,” they add. If you find that you still experience motion sickness despite taking antihistamines, you can also opt for a non-drowsy motion sickness formula that contains the active ingredient meclizine, Gattas says. This should give you added protection from motion sickness without making you dangerously sleepy while traveling. The Cleveland Clinic says there are several simple homeopathic ways to improve your symptoms of motion sickness—and thankfully, they come with no side effects at all. For example, some people find relief from motion sickness by sucking on hard candies made with peppermint or ginger, or by inhaling scents with those ingredients. Additionally, breathing freshly circulated air, whether from an air vent or open window, can help significantly. Lay back if possible, and close your eyes or look at an object in the far distance, rather than a phone, tablet, or book. Some individuals also find relief from their symptoms by wearing acupressure wristbands. Finally, staying hydrated, avoiding heavy meals, and abstaining from alcohol can all help minimize the physical strain of travel. For more health news sent directly to your inbox, sign up for our daily newsletter. In addition to medication and homeopathic interventions, the Cleveland Clinic says there’s one more thing you can do to minimize your risk of motion sickness. “You should always face forward when traveling. Where you sit can also make a difference to minimize disruptive motion,” their experts note. Exactly where you sit depends on what mode of transportation you choose, they add. In a car, sitting in the front passenger seat is optimal for motion sickness. On a plane, sitting over the wing results in the least bumpy ride. On a train or bus, you can choose any forward facing window seat, the health organization suggests. And, on a boat, they recommend sitting in the middle of the craft on the upper deck unless it’s a large cruise ship—then you want to be toward the bottom. Only after exhausting these other options should you explore medication to treat your motion sickness. RELATED: If You’re Over 70, Stop Taking This One Thing Every Day, Doctors Say.