Benadryl is the brand name for a range of over-the-counter products that are used to manage allergies. Generally, most of these products contain a non-drowsy antihistamine such as acrivastine or cetirizine. Benadryl Plus (also known by the full name Benadryl Allergy Relief Plus Decongestant), is a product that contains the hay fever medication acrivastine alongside the decongestant medication pseudoephedrine. This product is formulated as capsules, and it is the only Benadryl product that combines an antihistamine with a decongestant. In countries other than the UK, there is a different Benadryl product called Benadryl Allergy Plus Congestion available. These tablets combine the drowsy antihistamine diphenhydramine with phenylephrine, which is also a decongestant. There is also a children’s version of the same product that comes as a liquid called Children’s Benadryl Allergy Plus Congestion.
Antihistamines can help relieve allergy symptoms, such as a runny nose, sneezing, itchy and watery eyes and an itchy nose or throat. They work well for conditions like hay fever, pet allergies, and dust allergies. If you are also experiencing nasal congestion due to your allergic condition, a combined product with a decongestant can help relieve that stuffy blocked-up feeling.
During an allergic reaction, your immune system releases a chemical called histamine, which is responsible for the bothersome symptoms. Antihistamines stop histamine binding to its target sites in your body, reducing the immune response and also the symptoms. The chemical structure of non-drowsy antihistamines makes them less likely to enter the brain via the blood. This makes them less likely to cause drowsiness compared to drowsy antihistamines. Pseudoephedrine helps relieve nasal congestion, which can occur due to allergies. The nasal congestion is caused by swelling (inflammation) of blood vessels in your nose. Pseudoephedrine is a vasoconstrictor and works by narrowing the blood vessels in your nose. This leads to a reduction in the swelling, leading to an improvement in breathing through your nose.
Like all medications, don’t take them if you previously had an allergic reaction to the medication, if you have severe kidney or liver problems, or if you have other medications or medical conditions where you would normally discuss with your doctor or pharmacist before starting something new. You should also make sure you do not take a combined antihistamine and decongestant product alongside another antihistamine or decongestant medication.
As with all medications, some people may experience side effects. All antihistamines have the potential to cause drowsiness, even antihistamines that are classed as non-drowsy. However, you are much less likely to experience drowsiness from taking a non-drowsy antihistamine like acrivastine than you are from taking a drowsy one like diphenhydramine. Potential side effects from decongestants like pseudoephedrine and phenylephrine can include nausea, vomiting, headache, dry mouth, restlessness, anxiety, and difficulty sleeping. Occasionally, some people may develop fast or irregular heartbeats. If this happens, you should stop using the medication and seek medical advice.