Before taking an antihistamine to battle allergy symptoms, the Food and Drug Administration suggests to read the label first.The FDA recently issued a statement to doctors and pharmacists that warned of possible reactions when taking Hismanal, an antihistamine prescribed by doctors, in combination with other drugs.Hismanal should not be taken with drugs like Crixivan and Norvir, anti-depressants like Prozac and Zoloft and anti-asthma medication Zyflo. Antibiotics like Biaxin and TAO, and Posicor, a hypertension drug, should also be avoided with Hismanal, according to the statement. “Hismanal is associated with risks of death due to irregular heart rhythms when taken with certain other drugs and when used at higher than the recommended labeled dose,” the statement said.Heather Tinker, an undergraduate student in the College of Pharmacy at Ohio State, saw the statement at the Kroger pharmacy she works for. From experience, she said has not seen Hismanal used often.”We have a bottle (of Hismanal) here that is more than a year old,” she said.Tinker said antihistamines such as Claritin and Allegra are used more frequently and are considered to be much safer.”I think doctors are catching on that Hismanal isn’t the best thing to use,” she said.The prescribed dosage is one 10-milligram tablet per day, Tinker said.The statement also warns not to take Hismanal with grapefruit juice.Hismanal and grapefruit juice are metabolized by the same enzymes in the liver, she said. When they interact, grapefruit juice causes the same side effect that combining Hismanal with other drugs has.Hismanal has been on the market for about four years, Tinker said.Studies to test drugs usually don’t use a large enough portion of the population, said Lou Mavko, associate director of the pharmacy at OSU Medical Center.”Most antihistamines do have side effects, but most of them aren’t seen in a majority of patients,” he said.The list of side effects for most drugs is a mile long, but it is required by law to list them, Mavko said.”The consumer can get pretty scared,” he said.