Potassii Nitras. Potassium Nitrate. Kno3 = 100.92. Synonyms. - Nitre. Saltpetre.

Source

Purified native Saltpetre.

Characters

Colorless, transparent, six-sided rhombic prisms or a crystalline powder, odorless, and having a cooling, saline and pungent taste. Solubility. - In 3.8 parts of water; very sparingly soluble in Alcohol.

Impurities

Sulphates, chlorides and lime, and the metals.

Potassium Nitrate is used to prepare Argenti Nitras Dilutus.

Dose, 5 to 20 gr.; .30 to 1.20 gm.

Preparation

Charta Potassii Nitratis

Potassium Nitrate Paper. Potassium Nitrate, 200; distilled water, 800. Dissolve the Potassium Nitrate in the Distilled Water. Immerse strips of white, unsized paper in the solution, and dry them.

Action of Potassium Nitrate

External

Nothing noteworthy.

Internal

Stomach and Intestines. - It is liable to cause nausea, vomiting, diarrhoea, symptomatic of the gastritis and enteritis produced by it.

Blood

Owing to its high diffusion power it quickly passes into the blood unchanged. External to the body, nitrates prevent the coagulation of the blood, or dissolve the clot if it be already formed; but it is not known that they have any effect on the blood in the body.

Heart

Potassium nitrate is a powerful cardiac depressant, causing the beats to become feeble and few. Large doses lead to great weakness, fainting, and death.

Kidneys

Small doses are diuretic from their direct action on the renal cells, but large ones are liable to inflame the urinary passages, causing haematuria. The drug is excreted unchanged in the urine.

Skin

Potassium nitrate is a mild diaphoretic.

Lungs

Large doses retard respiration and tend to paralyze unstriped muscular fibre.

Therapeutics of Potassium Nitrate

Internal

Blood. - On account of its supposed action in preventing the coagulation of the living blood, it has been used in rheumatic fever and many inflammatory conditions, but it is now discarded. Probably, as it is a cardiac depressant, it only does harm.

Kidneys And Skin

It is sometimes employed as a diuretic and diaphoretic in febrile conditions, but the acetate and the citrate are much preferable.

Asthma

Potassium nitrate is an anti-spasmodic for the reason given above. For the treatment of this symptom potassium nitrate paper, in pieces about 1 1/2 inches 4. cm. square, is lighted, one at a time, and the patient inhales the fumes. Ringer considers it better to dip the paper also into a solution of potassium chlorate, and to burn a piece large enough to fill a whole room with the fumes. This treatment often relieves, and nitre is a common ingredient of so-called asthma powders.