An antihistamine can be very helpful if you or someone you know is suffering from the uncomfortable symptoms due to allergies, but they do have side effects just like any other medication. Antihistamines alleviate allergy symptoms such as runny nose, sneezing, itchy nose and throat and itchy, watery eyes. If you are taking or plan to take an antihistamine, it is important to know what the potential side effects are even though these kinds of drugs are considered very safe medications.
Antihistamine and Drowsiness
The most common side effect of an antihistamine is drowsiness. Antihistamines such as diphenhydramine and chlorpheniramine are more likely to cause drowsiness than any of the newer antihistamines available. This unwanted side effect of drowsiness occurs less frequently with the newer antihistamines such as citrizine, desloratadine, fexofenadine and loradtadine. Yet, you should still keep this potential side effect of drowsiness in mind while taking an antihistamine, or administering them even though they are considered non-drowsy drugs. It is also important to remember that alcohol will increase the side effect of drowsiness when you are taking an antihistamine, too.
People have allergy symptoms because certain harmless substances like pollen or animal dander enter the body and trigger the body to release histamine since the body mistakes the harmless substance for a harmful one. Antihistamines work by binding receptors of certain cells in the body that histamine usually binds to. This results in the histamine receptors being blocked and makes histamine unable to affect the body any longer.
Why Drowsiness is a Side Effect of Antihistamines
The problem of drowsiness arises with these medications because antihistamines can also end up blocking acetylcholine receptors also. When acetylcholine receptors are blocked, reuptake cannot happen any longer. After this occurs, too much acetylcholine builds up in the body which leads to the antihistamine side effect of drowsiness. More modern antihistamines like certizine, desloratadine, fexofenadrine and loratadine have a greater accuracy with only combining with antihistamine receptors and not combining with acetylcholine receptors as much. That is why these antihistamines usually do not cause drowsiness like the ones that contain chlorpheniramine and diphenhydramine. You must remember that even though these more modern antihistamines are created to be non-drowsy. they still have a slight potential to still make you drowsy.
Drowsiness could get in the way of the things you need to do during the day, so it is always a good idea to take this medication at night, before you go to bed as opposed to taking it when you wake up in the morning. If you take it in the morning, you may feel fatigued all day. The side effect of drowsiness from antihistamines can also impair your ability to safely drive or operate any kind of heavy machinery. An antihistamine can be a life changing medication for those suffering with severe allergy symptoms, but as with all medications, you and your doctor have to decide if the benefits of antihistamines outweigh the possible risk of side effects such as troublesome drowsiness.