While many antihistamines cause drowsiness, some, particularly first-generation ones like diphenhydramine (Benadryl) and newer ones like desloratadine, can paradoxically cause anxiety, restlessness, insomnia, or a rapid heart rate in some individuals, often due to central nervous system stimulation or interaction with neurotransmitters. Even second-generation antihistamines like fexofenadine (Allegra) and cetirizine (Zyrtec), though less common, might also trigger anxiety or mood changes in sensitive people.
Anxiety caused by antihistamines should go away once you stop taking the medication. If you notice you feel more nervous in the hours following a dose of these allergy medications, speak with your provider about alternatives.
Hydroxyzine is an antihistamine. It is approved for the treatment of anxiety. However, hydroxyzine is also used to treat difficulty sleeping, nausea, vomiting, itching, skin rash, and allergies.
Histamine-induced anxiety can feel like restlessness, a racing heart, palpitations, or a sense of unease.
In children, hydroxyzine is approved to treat all of the same conditions as adults. However, the dosage in children is usually much lower.
Parents may want to know if Zyrtec will cause anxiety or behavioral issues. Generally, these issues should not occur with the proper dosage.
Use of hydroxyzine is contraindicated in patients with known acquired or congenital QT interval prolongation, or with a known risk factor for QT interval prolongation such as cardiovascular disease, significant electrolyte imbalance (hypokalaemia, hypomagnesaemia), family history of sudden cardiac death, significant ...
How to Reduce Histamine and Anxiety
Many people believe they experience a “histamine dump.” This phenomenon usually happens at night when your body releases a sudden surge of histamine. A histamine dump can interrupt your sleep and cause headaches, flushing, itching, anxiety, and a racing heart.
Furthermore, intraperitoneal injection of histamine has been found to increase adrenocorticotrophic hormone release in rats. We speculated that if histamine levels are higher due to the presence of the 314T variant allele, Cortisol levels will be increased subsequently.
The most common type of medication prescribed for anxiety disorders are SSRIs, like Lexapro and Viibryd, as a first-line treatment and have relatively fewer side effects compared to other types of antidepressants, like MAOIs.
Hydroxyzine is used to help control anxiety and tension caused by nervous and emotional conditions. It can also be used to help control anxiety and produce sleep before surgery. This medicine is also used to relieve symptoms of allergic conditions (eg, chronic urticaria and atopic and contact dermatoses).
Stopping antihistamines abruptly—especially after long-term or high-dose use—can lead to withdrawal-like symptoms in some individuals. These symptoms can show up even when no allergens are present, such as: Anxiety: Feelings of unease, nervousness, or panic without a clear cause.
Features of toxicity are likely to develop within 6 hours of overdose and include tachycardia, blood pressure disturbances, dry mouth, ataxia, agitation, psychosis and, uncommonly, convulsions or arrhythmias. Sedation is exacerbated by co-ingestion of other central nervous system depressants including alcohol.
Defining high-functioning anxiety
They often are successful in careers or other roles, yet internally struggle with persistent feelings of stress, self-doubt and the fear of not measuring up. They feel extremely uncomfortable inside and struggle with significant self-criticism.
Excess histamine can cause a variety of different symptoms which very often mimic allergic reactions. The most common symptoms are rashes (e.g. hives), itching, flushing, irritable bowel syndrome (IBS), indigestion, breathlessness, palpitations, migraines, dizziness, anxiety/panic, joint aches and nasal congestion.
Histamine levels are another potent downstream target. Allergic symptoms exacerbate during nighttime and plasma histamine levels exhibit nocturnal peaks. In mastocytosis patients, peak levels of plasma histamine were observed in the early morning with the lowest in the afternoon (19).
Vitamin C. Vitamin C is a very common and well-known nutrient to strengthen the immune system and reduce inflammation. Vitamin C is also required to produce the necessary enzymes for the process of histamine breakdown, making it a vital anti-histamine nutrient.
Antihistamines are known to cause extreme drowsiness; however, in certain people, they can cause insomnia, excitability, anxiety, restlessness, and a rapid heart rate.
Anti-anxiety medications help reduce the symptoms of anxiety, such as panic attacks or extreme fear and worry. The most common anti-anxiety medications are called benzodiazepines. Benzodiazepines are a group of medications that can help reduce anxiety and make it easier to sleep.
Vitamin B12 supports the methylation process—a biochemical pathway that helps the body detoxify and regulate histamine levels. When B12 is lacking, methylation slows down, leading to higher histamine concentrations in the blood.
Hydroxyzine can be a helpful tool for managing anxiety, especially when you need quick relief without the risks of controlled substances. While it's not typically a first-choice or long-term solution, it fills an important role for many people dealing with anxiety symptoms.
As of this writing, some of the anxiety medications with the fewest reported side effects and least risk of side effects include:
Hydroxyzine is prescribed as a short-term anxiety treatment. You may take it by itself or alongside another anxiety medication, such as buspirone (Buspar) or escitalopram (Lexapro), that's taken every day. Hydroxyzine can provide symptomatic anxiety relief while you're waiting for the longer-term medication to kick in.