Antihistamines are drugs that are available without needing a doctor's prescription, although don't let that fool you, as antihistamine side effects are commonly experienced when taking them. These drugs work by getting into histamine receptor sites, and when they do this, they prevent common allergy problems from occurring. Many people regularly take antihistamines during allergy season, although they can be use as needed at any time of the year. There are side effects from antihistamines that are more common than others, however, these are the most common side effects most people will feel.
- Drowsiness: This is the most common side effect from most antihistamines, however, they are most common when taken with other medications, especially other cold or allergy medications, beta blockers, and special precaution should be taken if you're going to take them along with central nervous system depressants, such as alcohol, benzodiazepines, tranquilizers, or pain medications.
- Dry Mouth: A lot of antihistamines have side effects that can be as mild as a dry mouth. You will want to make sure to drink plenty of fluids to stay hydrated when taking them. The dry mouth occurs because the antihistamine is being used to "dry up" certain fluids, like mucous or congestion.
- Blurred Vision: One of the most severe antihistamine side effects is experiencing blurred vision, especially if too much of an antihistamine is taken. This is another reason why it's important to try avoiding any driving or operating of machinery or situations where you need to be fully alert.
- Urine Retention: This is one of the least common antihistamine side effects, but can become more common if the antihistamine is used over a long period of time. Some people have this as one of the antihistamines side effects as they tend to gain more water, thus retaining urine and making it more difficult to urinate or not having the urge to urinate as often.
- Hallucinations: This side effect is generally only experienced in those who have taken way more than they were supposed to, or if they were taken with other medications or alcohol. The hallucinations can be mild, and just experienced as color distortion or a more "vivid" like vision, or can result in full on hallucinations of seeing things that aren't there, especially in high doses.
- Abdominal Pain: This is one of the rarely seen side effects, especially if taken rarely and as directed. Antihistamines can cause slight abdominal pain if you have a sensitive stomach, as the acidity in them can cause a lot to build in the stomach and then also come up in into the throat.
- Heart Burn: This side effect is also typically seen in patients who have to take a bunch of other regular medications, as the acidity needed in the stomach to break down the pills recognizes more acidity is needed to break down the pills, so often the acidity can cause heart burn.
- Anxiousness: This is one of the antihistamine side effects that is again most common for specific people, mainly being children. Many children can feel an anxious or restless feeling after taking an antihistamine, so using the lowest dose possible is best.
- Irritability: Just like increased anxiety or anxiousness seen in some adults and mainly children, irritability can be an adverse side effect. Although with most people they will experience drowsiness, some may actually become more irritable.
- Depressed respiratory system: Since antihistamines often make people sleepy, this results in usually a depressed respiratory system, which is why they should not be taken with other central nervous system depressants because it can slow the heart to dangerous rate.
Of course, before you take any medication, it's important that you talk to your doctor or a pharmacist before taking any kind of medication so that you can avoid any drug interactions or avoid any serious health results that could ensue.