When you come into contact with an allergen such as pollen, mold, animal dander or dust, your body produces a chemical called histamine. Antihistamines reduce the effects of histamine on our body by blocking the receptors in our brains that usually react to it23.
Benadryl is both an antihistamine and an anticholinergic medication. This means that Benadryl also blocks the effect of acetylcholine. This is a chemical in the brain that helps send messages between cells. Blocking acetylcholine can cause temporary drowsiness, confusion, and memory loss.
First-generation (older) allergy medications may cause memory loss. However, newer antihistamines, cetirizine (Zyrtec) and loratadine (Claritin) are less likely to cause problems with memory and cognition.
What is this? Antihistamines are also one of the groups of drugs known for causing brain fog and memory loss. Disturbingly, even over-the-counter antihistamines like Benadryl can greatly increase the risk of dementia. The sedative effects of these drugs can leave you feeling drowsy.
Rarely, they can cause acute self-limited liver injury. One study has reported a more serious long-term effect, a 3.5-fold increase in the risk of gliomas, a common type of brain tumor in patients with long-term antihistamine use for allergic conditions.
Yes, most people can take antihistamines every day, if they have daily symptoms of their allergies.
Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: difficulty urinating, fast/irregular/pounding heartbeat, shaking (tremor), mental/mood changes (such as anxiety, confusion, nervousness, restlessness), weakness.
Mechanism of Injury. The cause of acute liver injury from cetirizine is not known. It is metabolized by the liver and a toxic metabolite may account for idiosyncratic injury.
Is it safe to use antihistamines every day? In general, most of the available over-the-counter antihistamines are safe for long-term use. There are some potential side effects and there are some cases where long-term antihistamine use can worsen urinary retention or narrow angle glaucoma.
You can also experience side effects from taking a regular antihistamine—like Zyrtec, Claritin, or Benadryl—including dry mouth, confusion, flushing, visual impairment, and fever. What's more—getting off antihistamines can cause allergic reactions as well.
Side effects of antihistamines
sleepiness (drowsiness) and reduced co-ordination, reaction speed and judgement – do not drive or use machinery after taking these antihistamines. dry mouth. blurred vision. difficulty peeing.
Antihistamines work by having a calming effect on the brain, helping you to feel less anxious. As with benzodiazepines, this type of medicine is only effective when used for a short period of time.
People who take antihistamines regularly may build up a tolerance to the drug, which means they need to take higher and higher doses to get the same effect. This can lead to addiction. Antihistamines are often addictive because they work by blocking histamine receptors.
Newer-generation antihistamines (cetirizine, loratadine, desloratadine) are hydrophilic, do not cross the blood brain barrier, and have much less associated sedation.
You should not use Zyrtec-D if you have narrow-angle glaucoma, severe high blood pressure (hypertension), severe coronary artery disease, if you are unable to urinate, or if you are allergic to hydroxyzine (Atarax, Vistaril). Do not use this medicine if you have taken an MAO inhibitor in the past 14 days.
The over-the-counter allergy medication cetirizine (Zyrtec and generic) has been linked to depression, as has another type of drug, montelukast (Singulair), which is often used to treat people with allergic asthma.
Antihistamines
Antihistamines are known to cause extreme drowsiness; however, in certain people, they can cause insomnia, excitability, anxiety, restlessness, and a rapid heart rate.
Histamine plays a role in our appetite. When antihistamines block histamine, our appetite can increase. This, plus side effects like drowsiness, could lead to weight gain.
Claritin and Zyrtec are effective and safe for most people with minor allergies. However, as with all medications, there may be some side effects. Loratadine—present in Claritin—may not be safe for people with severe liver conditions.
Do not use with any other antihistamines applied to the skin (such as diphenhydramine cream, ointment, spray) because increased side effects may occur. Cetirizine is very similar to hydroxyzine and levocetirizine. Do not use these medications while using cetirizine.
Official answer. Cetirizine can be taken at any time of the day. In most people it is non-sedating, so they take it in the morning. However, a percentage of people do find it to be sedating so if it does make you drowsy it is best to take it in the evening.
by Drugs.com
The elimination half-life of Zyrtec is between 8 to 9 hours. It takes approximately 5.5 x elimination half-life for a medicine to be cleared from your system. For Zyrtec this is 5.5 x 9 hours which is about 2 days.