Guide To Over-The-Counter Antihistamines

Over-the-counter antihistamines come in a variety of forms. Patients often take them as a tablet. Nasal sprays and eye drops are also available. In general, newer antihistamines are associated with fewer side effects than older ones. When using an over-the-counter product, patients should follow all directions on the package and never exceed the recommended dose. Over-the-counter products are intended for short-term treatment. Patients should see their doctor if their symptoms persist beyond one week. 

Antihistamines are a major seasonal allergies treatment. Many patients also take them as an allergic rhinitis treatment. They will help treat many allergy symptoms, including congestion, itchy eyes, sneezing, and a runny nose. Patients may even take an antihistamine for hives. Most patients will want a non-drowsy antihistamine so that they can keep on task during the day. Of course, individuals may want different ones based on their needs and overall health. This is why understanding the different OTC antihistamines is vital.


Diphenhydramine is an older, first-generation antihistamine. It helps relieve symptoms associated with hayfever, the common cold, and allergies. This medication is also used to treat motion sickness and some symptoms of Parkinson's disease. As a first-generation antihistamine, it causes drowsiness. Patients can find it in some over-the-counter sleep aids. In addition to drowsiness, patients taking this antihistamine could experience thickening of bronchial secretions, dizziness, headaches, and reduced coordination. The medication could also cause dry mouth, fatigue, heart palpitations, confusion, and low blood pressure. 

Children under two years old should not take this antihistamine. Patients taking this medication should use caution while driving and operating machinery. Consuming alcohol while taking this medication could cause increased drowsiness or dizziness. Individuals with a history of thyroid, liver, or kidney issues should consult a doctor before using this medicine. Patients with heart disease, low blood pressure, urination issues, glaucoma, or breathing issues should also ask a doctor about this medication first.


Cetirizine is a second-generation antihistamine. It is used to treat hay fever as well as allergies to dust mites, animal dander, and mold. In addition, this medication helps treat itching and redness from hives. Patients can take this drug as an extended-release or regular tablet. It is available as a chewable tablet and a liquid too. Pregnant women need to consult a doctor before using this medication. Individuals with liver disease or kidney disease should consult a doctor before taking it as well. Patients with allergies to hydroxyzine should not use cetirizine. 

During treatment with this medicine, individuals may develop stomach pain, drowsiness, or dry mouth. They may also feel excessively tired. Some individuals could experience diarrhea or vomiting as well. Patients need to let their doctor know if these side effects are severe or persistent. In rare cases, individuals have developed swallowing problems and breathing difficulties. If these are present, patients should inform their doctor immediately. Cetirizine may interact with a wide range of medicines. Thus, patients should let their pharmacist and doctor know about all medicines they take. They should take particular care to mention those used to treat anxiety, sleeping issues, seizures, or mental health conditions. Doing so helps patients avoid side effects. 


Fexofenadine is intended to treat seasonal allergies in children and adults. It also treats hives and itching related to chronic idiopathic urticaria. Patients over sixty-five years old should check with a doctor before using this medicine. Individuals with kidney disease should do this as well. Patients should not take this medication with any fruit juice, including orange, apple, or grapefruit juice. They should only do so with water. Patients who use the disintegrating tablets need to take them on an empty stomach. 

Antacids can interfere with the absorption of fexofenadine. Thus, patients should not take them within two hours of using this antihistamine. This medication's side effects include back pain, headaches, sinus pain, sore throat, and stuffy nose. Patients who notice pain, a new or worsening cough, fever, chills, or fatigue during treatment should let their doctor know right away. Patients should check with their pharmacist or doctor before using fexofenadine with certain medications to avoid interactions. This includes erythromycin, ketoconazole, and opioids. Sleeping pills, muscle relaxers, and anticonvulsants also cause interactions with this medication.


Loratadine helps relieve cold and allergy symptoms. This includes sneezing, skin rashes, watery eyes, hives, and a runny nose. In addition, it can treat hives and itching associated with chronic skin conditions. Patients with asthma, liver issues, or kidney conditions should check with a pharmacist or doctor before taking this antihistamine. Individuals with allergies to desloratadine should not take it. 

The chewable forms of this medication could contain phenylalanine. Thus, phenylketonuria patients should consult their doctor first. Loratadine may cause drowsiness. Other commonly reported side effects include headaches, stomach pain, vomiting, dry mouth, hyperactivity, and anxiety. Patients should stop using this medication immediately and call their doctor if they develop a severe headache, a fast or irregular heartbeat, or feel lightheaded.


Clemastine is a first-generation antihistamine first used in the 1960s. It is intended to treat allergies. Patients who are sixty years old and older may have an increased risk of side effects with this medicine. Breastfeeding women should not take it. Patients who take linezolid or methylene blue should check with their doctor first. This will help them make sure that this antihistamine is safe. 

Individuals who have used certain medications within the last two weeks also need to talk to their doctor. Examples include certain Parkinson's disease and depression medications, such as isocarboxazid and selegiline. Taking these medicines together could cause dangerous increases in blood pressure. Side effects of this antihistamine include stomach pain, dizziness, and sleepiness. Patients who notice changes in their balance should let their doctor know right away. Individuals should not use alcohol while taking clemastine.