Taking antihistamines long-term, especially older types, has potential risks, but modern, non-sedating antihistamines (like cetirizine, loratadine) are generally considered safe and effective for years under medical guidance, though some studies link strong anticholinergic antihistamines (like Benadryl) to increased dementia risk and others suggest rare glioma links. It's crucial to use second-generation antihistamines, discuss any long-term use with a doctor, especially for older adults or those with existing conditions, to manage potential side effects like tolerance or rare issues like withdrawal itching.
Tolerance is not a problem. 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.
Combining this medication with alcohol or other depressants (including antihistamines, narcotics and some dental anesthetics) can make side effects more severe.
Yes, antihistamines can cause headaches, which for some people might manifest as or trigger migraines, though headaches are a common side effect of both older (sedating) and newer (non-sedating) types, notes GoodRx and Healthdirect. While antihistamines can help with allergy-related headaches, the medication itself can sometimes induce head pain or be linked to migraine pathways, with some studies suggesting histamine's role in migraine mechanisms, say researchers from MDPI and Springer Nature.
Some antihistamines you only take once a day. Others, you can take more than once a day. How long you can take it: You can take some types of antihistamines long term. But others are only for short-term use (a few days).
Fexofenadine (Allegra)
It's one of the least sedating second-generation antihistamines, making it a safe option for long-term use if you take it as your doctor prescribes.
If you take antihistamines to ease symptoms of an allergy, you'll need to keep taking them while you have contact with the allergen. So, if you have hay fever, you may need antihistamines every day during the spring and/or summer. Some people do have to take antihistamines every day.
CONCLUSIONS. The first-generation antihistamines negatively affect mood, sleepiness, alertness, and cognitive and psychomotor functioning in adults and children. As a result, these medications can interfere with performance and safety, even when taken the night before.
For example, respiratory symptoms associated with histamine receptor intolerance include rhinorrhea, rhinitis, nasal congestion, dyspnea, and sneezing [19,21]. Histamine receptors are present in the skin; therefore, there will be skin manifestations, including pruritis, flushing, urticaria, dermatitis, and swelling.
H1 first-generation antihistamines: Common adverse effects include sedation, cognitive impairment, and anticholinergic adverse effects such as dry mouth, urinary retention, constipation, and blurred vision. Dizziness, tinnitus, and delirium may occur at high doses.
The action of mirtazapine is an antagonist of certain adrenergic and serotonin receptors, and, furthermore, the drug is used strong as antihistamine, and it is occasionally defined as a noradrenergic and specific serotonergic antidepressant (NaSSA).
People with conditions like glaucoma, enlarged prostate, heart disease, high blood pressure, asthma, liver or kidney disease, epilepsy, overactive thyroid, diabetes, or those who are pregnant/breastfeeding, or giving them to young children (under 2-6 years), should avoid or be cautious with antihistamines, especially older, sedating types, and should consult a doctor or pharmacist first due to risks like worsening urinary retention, glaucoma, or causing serious harm in kids.
have a heart problem – amitriptyline can make some heart problems worse. have liver or kidney problems. have epilepsy – amitriptyline can increase seizures or fits. have ever taken any medicines for depression – some antidepressants can affect the way amitriptyline works.
In general, wean gradually by 25-50% of the daily dose every 1-4 weeks.
Antihistamines, which are commonly used to treat symptoms such as a runny nose or sneezing, are generally safe for patients with abnormal heart conditions. However, the FDA has warned that antihistamines taken in conjunction with some high blood pressure medications may cause a spike in blood pressure.
FDA is warning that patients discontinuing the antihistamine allergy medicines cetirizine or levocetirizine after long-term use may experience severe pruritus. This has been reported in patients using the medicines daily, typically for at least a few months and often years.
Histamine intolerance is a condition in which your body doesn't break down histamine in foods. The histamine then builds up and causes symptoms like diarrhea, shortness of breath, and headaches.
High histamine levels are often caused by a deficiency in the enzyme DAO, which helps to break down histamine.
Under your skin. Near blood vessels and lymph vessels. In nerves. In your lungs and intestines.
If you're using oral antihistamines very often, you might have wondered if it's OK to keep relying on antihistamines to control symptoms of allergies. The good news is there's no research evidence to suggest regular, long-term use of modern antihistamines is a problem.
The study found that people had a higher risk for dementia if they took:
Thus, histamine is an important regulator of sleep—wake cycles and probably contributes to the diurnal changes in other brain functions as well. Histamine also reduces seizure activity, another H1 receptor-mediated effect. H1 antagonists increase seizure onset and/or seizure duration in humans and animals.
Antihistamines — such as Zyrtec, Claritin, and Allegra — work quickly and can usually be taken safely long term. Antihistamine nasal sprays are the closest alternative to oral antihistamines. Astepro (azelastine) is an example. These medications work for allergies in the same way as Zyrtec, Claritin, and Allegra.
Corticosteroid sprays, also called glucocorticoid sprays, prevent and relieve nasal allergy symptoms. These medicines are very effective on their own for treating ongoing or seasonal hay fever.