Antazoline is a 1st generation
antihistamine
Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provid ...
with
anticholinergic
Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system.
These agents inhibit the parasympathetic nervous sys ...
properties used to relieve
nasal congestion
Nasal congestion is the blockage of nasal breathing usually due to membranes lining the nose becoming swollen from inflamed blood vessels.
Background
In about 85% of cases, nasal congestion leads to mouth breathing rather than nasal breathin ...
and in
eye drop
Eye drops or eyedrops are liquid drops applied directly to the surface of the eye usually in small amounts such as a single drop or a few drops. Eye drops usually contain saline to match the salinity of the eye. Drops containing only saline ...
s, usually in combination with
naphazoline
Naphazoline is a medicine used as a decongestant, and a vasoconstrictor added to eye drops to relieve red eye. It has a rapid action in reducing swelling when applied to mucous membranes. It is a sympathomimetic agent with marked alpha adrenerg ...
, to relieve the symptoms of
allergic
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic der ...
conjunctivitis
Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The ...
. To treat allergic conjunctivitis, antazoline can be combined in a solution with
tetryzoline
Tetryzoline (also known as tetrahydrozoline) is a drug used in some over-the-counter eye drops and nasal sprays. Tetryzoline was patented in 1954, and came into medical use in 1959.
Side effects
Tetryzoline eye drops may cause blurred vision, ey ...
.
The drug is a
Histamine H1 receptor
The H1 receptor is a histamine receptor belonging to the family of rhodopsin-like G-protein-coupled receptors. This receptor is activated by the biogenic amine histamine. It is expressed in smooth muscles, on vascular endothelial cells, in the h ...
antagonist: selectively binding to but not activating the receptor, thereby blocking the actions of endogenous
histamine
Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Since histamine was discovered ...
and subsequently leading to the temporary relief of the negative symptoms brought on by histamine.
A large study on people 65 years old or older linked the development of
Alzheimer's disease and other forms of dementia to the "higher cumulative" use of first-generation antihistamines, due to their
anticholinergic
Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system.
These agents inhibit the parasympathetic nervous sys ...
properties.
References
H1 receptor antagonists
Imidazolines
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