Chloropyramine is a classical first-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 ...

drug approved in Eastern European countries (like

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...

) for the treatment of

allergic conjunctivitis Allergic conjunctivitis (AC) is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy. Although allergens differ among patients, the most common cause is hay fever. Symptoms consist of redness (mainly due ...

allergic rhinitis Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, i ...

, bronchial asthma, and other

atopic Atopy is the tendency to produce an exaggerated immunoglobulin E (IgE) immune response to otherwise harmless substances in the environment. Allergic diseases are clinical manifestations of such inappropriate, atopic responses. Atopy may have a ...

(allergic) conditions. Related indications for clinical use include

angioedema Angioedema is an area of swelling (edema) of the lower layer of skin and tissue just under the skin or mucous membranes. The swelling may occur in the face, tongue, larynx, abdomen, or arms and legs. Often it is associated with hives, which are ...

(Quincke's edema), allergic reactions to insect bites, food and drug allergies, and anaphylactic shock. Chloropyramine is known as a competitive reversible H₁ receptor antagonist (also known as an H₁ inverse agonist), meaning that it exerts its pharmacological action by competing with

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 ...

for the H₁ subtype histamine receptor. By blocking the effects of histamine, the drug inhibits the vasodilation, increased vascular permeability, and tissue edema associated with histamine release in the tissue. The H₁ antagonistic properties of chloropyramine can be used by researchers for the purposes of blocking the effects of

on cells and tissues. In addition, chloropyramine has some

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. Chloropyramine's anticholinergic properties and the fact that it can pass through the blood–brain barrier are linked to its clinical side effects: drowsiness, weakness, vertigo, fatigue, dryness in the mouth, constipation, and rarely — visual disturbances and increase of intraocular pressure.

Clinical dosage and administration

In cases of severe allergic reactions, chloropyramine can be injected intramuscularly or intravenously. Oral administration: In adults, 25 mg can be taken 3 to 4 times daily (up to 150 mg); in children over 5 years old, 25 mg can be taken 2 to 3 times daily. For external application, the skin or the eye conjunctiva can be treated up to several times a day by applying a thin layer of cream or ointment containing 1% chloropyramine hydrochloride.

Contraindications

Contraindications for parenteral or oral administration include

benign prostatic hyperplasia Benign prostatic hyperplasia (BPH), also called prostate enlargement, is a noncancerous increase in size of the prostate gland. Symptoms may include frequent urination, trouble starting to urinate, weak stream, inability to urinate, or loss o ...

peptic ulcer Peptic ulcer disease (PUD) is a break in the inner lining of the stomach, the first part of the small intestine, or sometimes the lower esophagus. An ulcer in the stomach is called a gastric ulcer, while one in the first part of the intestines ...

, pyloric and duodenal stenosis, uncontrolled

glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye rem ...

pregnancy Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

and breast-feeding. It is not intended for the management of acute

bronchospasm Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes di ...

Special warnings and precautions

Chloropyramine should not be used internally with alcohol, sedative drugs and hypnotics because of the potentiation of the effects. It should be used with caution in patients with

hyperthyroidism Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormones by the thyroid gland. Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause and therefore includes hyperthyroidis ...

, cardiovascular diseases and asthma. In children, it can induce agitation, and in many adult patients dizziness may be observed. Because of the pronounced sedative effect the preparation should be prescribed cautiously in drivers and people working with machines. 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

properties.

Drug interactions

Chloropyramine should not be used internally with MAO inhibitors. Because of its anticholinergic activity, concurrent administration with cholinomimetics is not advisable. General anesthetics, analgesic agents and psycholeptics potentiate the sedative effect of chloropyramine.

Trade names

* Allergopress, Chimpharm AD ( KZ) * Allergosan, Sopharma AD ( BG, GE, LV) * Suprastin, Egis Pharmaceuticals PLC ( GE, HU, KZ, LT, LV, UA, RU) * Supralgon, Biopharm JSC ( GE) * Supranorm-Tsiteli A, Rompharm Co. ( GE) * Synopen, Pliva d.o.o. ( BA, HR, RS)

Synthesis

The preparation begins with the condensation of 4-chlorobenzaldehyde with 1,1-dimethyethylenediamine. The resulting

Schiff base In organic chemistry, a Schiff base (named after Hugo Schiff) is a compound with the general structure ( = alkyl or aryl, but not hydrogen). They can be considered a sub-class of imines, being either secondary ketimines or secondary aldimine ...

is reduced. The resulting amine is then further reacts with 2-bromopyridine in the presence of sodamide. Chloropyramine synthesis 2

References

{{Histaminergics H1 receptor antagonists Chlorobenzenes Aminopyridines