Jalap. The tuberous root of Ipomea jalapa Nuttall (Nat. Ord. Convolvulaceae). Racine de jalap, Fr.; Jalape, Ger.

Extractum Jalapae Alcoholicum

Dose, gr.1/2—gr. ij.

Resina Jalapae

Resin of jalap. Dose, gr. ij—gr. v.

Pulvis Jalapae Compositus

Compound powder of jalap. (Jalap, 35 grm.; bitart. of potassa, 65 grm.) Dose, gr. x—3 j.

Composition

Jalap contains a resin, to which its purgative property is due. The resin consists of two varieties, one soluble, the other insoluble, in ether. The latter has been named convolvulin, or jalap-in, and is the more active purgative of the two. Various secondary products of considerable interest are obtained from the resin, but these possess no special importance from the therapeutical point of view.

Physiological Actions

As a cathartic jalap resembles, but it is much more active than, senna. It is apt to produce nausea, and tormina and tenesmus invariably accompany its purgative action. It usually operates in from two to four hours, but the rate at which it moves to affect the intestinal canal is not influenced by the amount administered. The stools are soft at first, and afterward liquid. Jalap does not produce haemorrhoids, nor does it cause a tendency to, or increase an existing, menorrhagia. The secretions of the intestinal canal are increased by it, and the recent researches of Rutherford and Vignal have demonstrated that jalapin (convolvulin) excites the flow of bile.

The action of jalap appears to be local. It is true that experiments in support of a contrary opinion have been made; but, in the conclusive test of the intra-venous injection of convolvulin, no purgative action has followed (Husemann).

Therapy

The resin of jalap being the active constituent, it should generally be preferred. It has the merit of being almost tasteless, and hence may be given readily to children.

Jalap is an efficient cathartic in the beginning of fevers, inflammations, and acute diseases requiring the use of such therapeutic means. Formerly calomel and jalap were much prescribed, but this combination has deservedly fallen into discredit. Occasionally the resin and calomel, in less ponderous doses than formerly given, may be used with advantage as a cathartic: Rx Resinse jalapae, hydrarg. chlor. mit., ext„ hyoscyami, āā gr. j. M. Ft. pil. no. j. Sig.: Take at bedtime.

As jalap in sufficient quantity causes free watery evacuations, it is a suitable purgative in anasarca and ascites. The most generally approved hydragogue purgative, under these circumstances, is the compound jalap-powder. The efficiency of this may be increased by the addition of podophyllum. A tea-spoonful of the compound powder, taken in the early morning, will usually produce several very copious, watery stools. Increased urinary discharge also is a not infrequent result of its action.

Jalap has the power to cause the expulsion of lumbrici. As a vermifuge it is not at all equal to the other approved remedies, but it is certainly useful as an adjunct. For example, santonin at night, and the resin of jalap and calomel on the following morning, is an effective method of expelling these parasites.

Jalap is, of course, contraindicated in inflammatory states of the intestinal canal. In overdoses it causes hypercatharsis, and it may excite violent gastro-enteritis and endanger life. With proper attention to the conditions in which it is admissible, and to the dosage, jalap is entirely safe, and is a very certain and efficient cathartic. An excellent vehicle for the administration of the resin of jalap is the sirup of rhubarb. Rx Resinae jalapae, grs. ij—grs. v; syr. rhei aromat., oz ss. M. This is especially suitable for children.