phenindamine

Toxicity

Symptoms of a phenindamine overdose include extreme sleepiness, confusion, weakness, ringing in the ears, blurred vision, large pupils, dry mouth, flushing, fever, shaking, insomnia, hallucinations, and possibly seizures.

Originator

Thephorin ,Roche, US,1947

Definition

ChEBI: Phenindamine is an indene.

Background

Phenindamine is an antihistamine. Phenindamine blocks the effects of the naturally occurring chemical histamine in your body. Antihistamines such as phenindamine appear to compete with histamine for histamine H1- receptor sites on effector cells. The antihistamines antagonize those pharmacological effects of histamine which are mediated through activation of H1- receptor sites and thereby reduce the intensity of allergic reactions and tissue injury response involving histamine release. It is used to treat sneezing, runny nose, itching, watery eyes, hives, rashes, itching, and other symptoms of allergies and the common cold. Symptoms of a phenindamine overdose include extreme sleepiness, confusion, weakness, ringing in the ears, blurred vision, large pupils, dry mouth, flushing, fever, shaking, insomnia, hallucinations, and possibly seizures.

Indications

Used to treat sneezing, runny nose, itching, watery eyes, hives, rashes, itching, and other symptoms of allergies and the common cold.

Manufacturing Process

A mixture of 750 grams of 1-methyl-3-benzoyl-4-hydroxy-4-phenylpiperidine and 2,500 cc of 48% hydrobromic acid is refluxed for about 20 minutes. It is then poured into 8 liters of water. An oily precipitate appears which on standing crystallizes. It is filtered and crystallized from about 3.5 liters of alcohol. 2-Methyl-9-phenyl-2,3-dihydrel-pyridindene hydrobromide, MP 201°203°C, is obtained.
A mixture of 680 grams of 2-methyl-9-phenyl-2,3-dihydrol-pyridindene hydrobromide, 6,000 cc of water and about 100 grams of Raney-nickel catalyst is hydrogenated at room temperature and at about 1,000 lb pressure for a period of three hours. The catalyst is filtered. The clear filtrate is treated with a solution of 240 grams potassium thiocyanate in 400 cc of water. A heavy solid precipitates from which the supernatant liquid is decanted.
The residue is dissolved in 10 liters of boiling alcohol with stirring in the presence of nitro gen. The solution is cooled to room temperature under nitrogen, and then allowed to stand overnight. 2-Methyl-9-phenyl-tetrahydro1-pyridindene thiocyanate separates in crystals of MP 188°-189°C. From the concentrated filtrate an additional amount is obtained. The corresponding free base, prepared by treating the slightly soluble thiocyanate in aqueous suspension with sodium hydroxide and extracting with ether, has a MP of 90°91°C. It forms a tartrate of MP 160°C.
The starting material was prepared by reacting acetophenone, methylamine and formaldehyde followed by treatment of the intermediate with sodium hydroxide.

brand name

Thephorin (Hoffmann-LaRoche).

Therapeutic Function

Antihistaminic

Pharmacokinetics

Phenindamine is an antihistamine. Phenindamine blocks the effects of the naturally occurring chemical histamine in your body. Allergies are caused by an excessive type 1 hypersensitivity response of the body to allergens, mediated by inappropriate histamine signalling. By inhibiting the binding of histamine, antihistamines decrease the normal histamine response from cells, consequently decreasing allergic symptoms.

Metabolism

Not Available