(Not official.) - Phenazonum, B. P. - C6H5(Ch3)2C3 Hn2o=l87.65. Synonym. - Phenyldimethylpyrazolone.


Aceto-acetic Ether is acted upon by Phenyl-hydrazine, when Phenylmonomethylpyrazolone, Ethyl Alcohol, and water are formed. Ch3 Coch2cooc2h5 + H2Nnhc6h5 = C6H5(Ch3)C3H2N2O+C2H5OH+H2O.

The Monomethyl compound is treated with Methyl Iodide and Methyl Alcohol. C6H5(Ch3)C3H2N2O+Ch5i=C6H5(Ch3)2C3Hn2o+HI.


Colorless, odorless, scaly crystals of a somewhat bitter taste. Solubility. - Freely in water, Alcohol and Chloroform.


Iron sulphate, iodide, and chloride, copper sulphate, iodine, arsenic iodide, carbolic, hydrocyanic, and nitric acids, potassium permanganate, salicylates, corrosive mercuric chloride, spirit of nitrous ether; all preparations of tannin give a white precipitate; chloral hydrate decomposes it unless in dilute solution.

Dose, 3 to 20 gr.; .20 to 1.20 gm.

Action and Therapeutics of Antipyrin

Antipyrin in small doses may moderately increase arterial pressure by direct stimulation of the heart (Wood); in large doses it is a cardiac depressant, the final fall of blood-pressure being certainly due, at least in part, to a direct action upon the heart. It also contracts the blood-vessels, being therefore a local haemostatic. It is a mild diuretic, and is quickly excreted in the urine as antipyrin. It may produce an erythematous rash. It rapidly reduces an elevated temperature by decreasing heat production, by direct action on the centre which presides over heat production, and to a much less extent increases heat dissipation. In large doses it is said to produce convulsions, later coma, and paralysis of motor nerves and muscles.

Antipyrin is given internally as a powerful antipyretic, in fevers of various kinds. It is also used as a haemostatic in haemorrhoids and epistaxis. It has been used with some success in diabetes. It is largely employed as an anti-neuralgic, relieving the pains of locomotor ataxia and other nervous affections, and as an anti-rheumatic. It has been highly recommended in chorea and epilepsy. Externally it is supposed to be an antiseptic, but irritation has followed its hypodermatic use. It is a local anaesthetic.

Salipyrin is prepared by the action of antipyrin upon salicylic acid in substance. It is a white, coarsely-crystalline powder with a rather sweetish taste, readily soluble in alcohol, but slightly in water. In chronic articular rheumatism and sciatica it has been successful, but it does not prevent relapses. It has been successfully used for spasmodic dysmenorrhoea. The dose is from 6 to 30 gr.; .40 to 2.00 gm.

Iodopyrin or iodantipyrin is supposed to have a hydrogen atom in the phenyl group of antipyrin replaced by iodine. It occurs in colorless, prismatic needles, which are tasteless. It is, with difficulty, soluble in cold water or alcohol, but readily when hot. It causes a fall of temperature and perspiration, but without collapse or shivering. It is doubtful if it has any advantage over antipyrin. The dose is from 2 to 15 gr.; .12 to 1.00 gm.



Antipyrin occasionally produces, in man, collapse, cyanosis, very slow respiration, a feeble and irregular pulse, vomiting and profound prostration. It is not known whether these symptoms have been due to impurities in the drug, but it is quite likely that they have arisen from improper dosage. Many deaths have been caused by this drug; it has been stated that during one epidemic of influenza in Vienna seventeen persons were killed by it.


Stimulation by Alcohol and Ether subcutaneously and by the mouth; Strychnine subcutaneously to stimulate the heart; warmth to the feet and body.