Antihistamine
The vast majority of marketed H-antihistamines are receptor antagonists and only a minority of marketed compounds are inverse agonists at the receptor. Clinically, H-antihistamines are used to treat allergic reactions and mast cell-related disorders. Sedation is a common side effect of H-antihistamines that readily cross the blood–brain barrier; some of these drugs, such as diphenhydramine and doxylamine, are therefore used to treat insomnia. H-antihistamines can also reduce inflammation, since the expression of NF-κB, the transcription factor the regulates inflammatory processes, is promoted by both the receptor's constitutive activity and agonist (i.e., histamine) binding at the H receptor.
Effects of long-term benzodiazepine use
Long-term benzodiazepine use may lead to the creation or exacerbation of physical and mental health conditions, which improve after 6 or more months of abstinence. After a period of about 3 to 6 months of abstinence after completion of a gradual-reduction regimen, marked improvements in mental and physical wellbeing become apparent. For example, one study of hypnotic users gradually withdrawn from their hypnotic medication reported after 6 months of abstinence that they had less severe sleep and anxiety problems, were less distressed, and had a general feeling of improved health. Those having remained on hypnotic medication had no improvements in their insomnia, anxiety, or general health ratings. A study found that individuals having withdrawn from benzodiazepines showed a marked reduction in use of medical and mental health services.