Hydroxyzine, sold under the brand names Atarax among others, is a medication of the antihistamine type.[3] It is used in the treatment of itchiness, anxiety, and nausea, including that due to motion sickness.[3] It is used either by mouth or injection into a muscle.[3]
Common side effects include sleepiness, headache, and a dry mouth.[3][4] Serious side effects may include QT prolongation.[4] It is unclear if use during pregnancy or breastfeeding is safe.[3] Hydroxyzine works by blocking the effects of histamine.[4] It is in the piperazinefamily of chemicals.[3]
It was first made by Union Chimique Belge in 1956 and was approved for sale by Pfizer in the United States later that year.[3][5] In the United Kingdom 28 doses cost less than a pound.[4] In the United States the wholesale cost in 2018 was about 0.05 USD per dose.[6] In the United States about 8 million prescriptions were written for hydroxyzine in 2016.[7]
Medical uses
Hydroxyzine is used in the treatment of itchiness, anxiety, and nausea due to motion sickness.[3]
Hydroxyzine is prescribed when the onset of an organic disease state manifests through anxiety, as generalized anxiety disorder, or in other more serious cases as psychoneurosis, and is therefore prescribed as a means of regulating normal function. Hydroxyzine has shown to be as effective as the benzodiazepine drug bromazepam in the treatment of generalized anxiety disorder.[8] A systematic review concluded that compared with other anxiolytic agents (benzodiazepines and buspirone), hydroxyzine was equivalent in efficacy, acceptability, and tolerability.[9]
Hydroxyzine can also be used for the treatment of allergic conditions, such as chronic urticaria, atopic or contact dermatoses, and histamine-mediated pruritus. These have also been confirmed in both recent and past studies to have no adverse effects on the liver, blood, nervous system, or urinary tract.[10]
Use of hydroxyzine for premedication as a sedative has no effects on tropane alkaloids, such as atropine, but may, following general anesthesia, potentiate meperidine and barbiturates, and use in pre-anesthetic adjunctive therapy should be modified depending upon the state of the individual.[10]
In other cases, the usage of hydroxyzine is as a form of non-barbiturate tranquilizer[11] used in the pre-operative sedation and treatment of neurological disorders, such as psychoneurosis and other forms of anxiety or tension states.[11]
Contraindications
The administration of hydroxyzine in large amounts by ingestion or intramuscular administration during the onset of pregnancy can cause fetal abnormalities—when administered to pregnant rats, mice and rabbits, hydroxyzine caused abnormalities such as hypogonadism with doses significantly above that of the human therapeutic range.[12] In humans, a significant dose has not yet been established in studies, and by default, the FDAhas introduced contraindication guidelines in regard to hydroxyzine.[12] Similarly the use in those at risk from or showing previous signs of hypersensitivity is also contraindicated.[12]Hydroxyzine is contraindicated for intravenous (IV) injection, as it has shown to cause hemolysis.
Other contraindications include the administration of hydroxyzine alongside depressants and other compounds which affect the central nervous system.[12] and if absolutely necessary, it should only be administered concomitantly in small doses.[12] If administered in small doses with other substances, such as mentioned, then patients should refrain from using dangerous machinery, motor vehicles or any other practice requiring absolute concentration, in accordance with safety law.[12]
Studies have also been conducted which show that long-term prescription of hydroxyzine can lead to tardive dyskinesia after years of use, but effects related to dyskinesia have also anecdotally been reported after periods of 7.5 months,[13] such as continual head rolling, lip licking and other forms of athetoid movement. In certain cases, elderly patients' previous interactions with phenothiazine derivatives or pre-existing neuroleptic treatment may have had some contribution towards dyskinesia at the administration of hydroxyzine due to hypersensitivity caused due to the prolonged treatment,[13] and therefore some contraindication is given to the short-term administration of hydroxyzine to those with previous phenothiazine use.[13]
