Thallinum

Thallin

Thallin. This is a proprietary designation to take the place of the difficult chemical name—tetrahydroparamethyloxy-quinoline. It must not be confounded with thallium, the name of one of the elements.

In its natural state thallin is a liquid, oily substance, having strongly basic qualities. It combines with acids to form salts, which occur in crystals. We have thus thallini sulphas, thallini hydro-chloras, thallini tartras, etc. The salts are soluble in water, the sulphate in the proportion of one to five, and more freely in boiling water. The dose ranges from two to five grains.

As respects physiological action, thallin corresponds to the other members of the series; it is antipyretic and analgesic. It is very active in reducing febrile temperature, the decline beginning within an hour, and reaching the lowest point in about three hours, when reaction sets in. A sweat is followed by a rigor, which announces the beginning of a rise in temperature. The amount of sweating corresponds to the dose, and the chill is more or less severe accordingly, but neither of these symptoms is as pronounced as they are in the case of any other remedies of the same group. The action of the heart and the respiration are reduced correspondingly to the amount of thallin administered, and the blood-pressure falls also in the same ratio. A toxic dose arrests the heart in the diastole. The effects of thallin on the blood are similar to those of the other agents of this class: it decomposes the haemoglobin, and the blood assumes a brownish tint. In this way the respiratory function of the blood is impaired, and hence the temperature falls, the excretion of urea lessens, and the exhalation of carbonic acid diminishes. It does not lessen to any considerable extent the sensibility of the sensory nerves, nor is it an active hypnotic. Toxic doses in animals cause insensibility and muscular resolution. Thallin is not an analgesic. It can not be administered for a long time or in large doses without risk of inducing asphyxia from destruction of the haemoglobin and arrest of the respiratory function of the blood.

Therapy

Thallin is an antipyretic and an antiseptic. It has been used in typhoid fever as a means of reducing the temperature. It is very certain, but some disadvantages attend its action. If considerable doses—five grains to fifteen grains a day—have been given, with the decline in temperature there occurs a more or less profuse sweat, and chills usher in another pyretic stage. Its utility is doubtful in typhoid fever. In other febrile maladies, in acute rheumatism, erysipelas, tuberculosis, etc., the reduction of temperature promptly follows the exhibition of thallin; but the effect is maintained for three or four hours only, and then occur the sweats and the chills announcing the beginning of another febrile movement. It has no pain-relieving power in acute rheumatism or other rheumatic affections, although it reduces the temperature.

Steffen praises the action of thallin in the febrile diseases of childhood. He gives one half grain to two grains twice or three times in the twenty-four hours. As the salts of thallin, preferably the sulphate or tartrate, are soluble in water, they can be administered hypoder-matically. The effect is much more powerful when given in this way. When taken by the stomach, if considerable doses are required to lower the temperature, Erlich finds it better to give small doses more frequently, instead of a few large doses at longer intervals.