Misgivings on mineral oil as a laxative

MISGIVINGS

ON MINERAL JAMES W.

Instructor

in Surgery, SAN

OIL AS A LAXATIVE*

MORGAN, M.D., F.A.C.S. University

of CaIifornia

FRANCISCO,

T

HE time has come to reassess the current opinion with regard to the merit of minera oiI as a Iaxative. There is perhaps no drug which has attained such a wide and universa1 currency for this purpose in the civiIized worId of today. Its acceptance is based on the beIief that minera oi1 is a bIand and innocuous intestina1 Iubricant, whiIe the numerous and considerabIe deIeterious effects which may foIIow its continued administration have faiIed to be recognized. In this paper attention wiI1 be drawn to the effects of minera oi1 in disturbing norma physioIogic processes, as we11 as to the pathoIogic changes which may attend its use. PHARMACOLOGY

The use of Iiquid paraffin for the treatment of intestina1 stasis was first suggested by RandoIph’ (1885). The beIief that the oi1 is an innocuous substance dates from the work of Robinson2 (Igoo), who stated, on the basis of cIinica1 observation, that the oi1 aIways passed through the digestive tract unchanged. He maintained that a11 of his patients showed an improvement in weight, heaIth and genera1 we11 being after its use, whiIe there was no discomfort even in cases in which as much as a pint was administered in a few hours. Arbuthnot Lane,3 however, shouId have most of the credit, or possibIy discredit, for the present wide use of minera oi1. His surgica1 principIes in the treatment of intestina1 stasis were soon discarded, but minera oi1, which he so vehementIy advocated as an adjunct to this treatment, is stiI1 with us. He strongIy objected to a11 Iaxatives, purgatives, dietary reguIation,

MedicaI School

CALIFORNIA

massage, increased fluids, Iavage and enemas, and remarked that “a11 these forms of treatment are tedious, dangerous and at best onIy paIIiative. Much more benefit can be obtained by the use of pure Iiquid parafin administered at reguIar intervaIs during the day. This substance has, as far as is known, no chemica1 action whatever; it cannot be absorbed in the human intestine, whiIe it faciIitates very materiaIIy the passage of the intestina1 contents. The motions cease to be firm, and they are much Iess buIky than before, for the reason that the amount of organisms which form a considerabIe proportion of norma feces is greatIy diminished.” The texts on pharmacoIogy suggest no rationa therapeutic basis for the use of Iiquid parafin, the chemistry of which is, to say the Ieast, uncertain. Authorities such as CIark,4 Wood5 and SoIIman6 agree that the oi1 is not absorbed and that it softens the feces. CIark says it acts by reducing the feces to a Iiquid condition; Wood, by its irritative action on the mucous membrane; SoIIman, by simpIy softening the feca1 mass. None of them uses the word “ Iubrication,” in spite of the fact that nearIy everyone thinks of the product as an “intestina1 Iubricant.” Bastedo’ (1915) cIaimed that there was no therapeutic difference between Iight and heavy Russian or American minera oiIs. Newman and GruenfeId8 regard mineral oiI as a desirabIe innocuous Iaxative but, having encountered many patients who exhibited indigestion after the administration of mineral oi1, came to the concIusion that these iI effects were the resuIt of excessive dosage. In their opinion which was based on “occasiona examinations of

* From the Department of Surgery, University of California MedicaI SchooI, San Francisco, under the auspices of the PheIan Fund for the Improvement of the Comfort of Bed-Ridden Patients, University of CaIifornia.

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this was the result of St001 specimens,” incompiete emuIsification of the excess oi1. They stated that minera oil does not act as a Lubricant, but that it becomes emuIsified and thereby causes the feces to be more Auid. Their hypothesis is based very IargeIy on the inconclusive cIinica1 observations in mice and men, of SchIagintweits and Loewe’O and upon some ffuoroscopic observations of Schwartz’” on movement of the barium mea1 in the transverse colon after a pIain water enema had been given. Any concIusions of Schwartz must be influenced by the fact that a pIain water enema is distinctiy an irritant to the mucosa. Our objections to the use of minera oi1 are based on the foIIowing physioIogic and pathoIogic considerations. PHYSIOLOGIC

CONSIDERATIONS

I. The rectum is not a reservoir. Functionaliy it is but a short passage to the exterior. The true reservoir is formed by the sigmoid, descending and transverse coIon and feces may remain in this portion of the bowe1 for some time without iII effect. Once the feces enter the rectum they shouId be evacuated by the estabIishment of the defecation reflex. NormaIIy the act of defecation is initiated by the passage of feea materia1 past the resistance of the peIvirecta1 junction, which is more commonIy caIIed the rectosigmoid. At this point there exists, if not a true anatomic sphincter, certainIy a physioIogic one. The entrance of the feces into the rectum may resuIt from a mass movement first described by HoItzknecht12 or possibIy just from overIoading of the peIvic coIon and the gradua1 pushing of its contents onward. The pressure in the rectum in an individua1 in the erect position amounts at ordinary times to about I o mm. of mercury. The defecation reflex does not take pIace unti1 the intrarecta1 pressure reaches to a point between 40 and 60 mm. of mercury (Best and TayIorX3). This reflex initiates a strong peristaItic contraction of the coIon, accompanied by shortening of the

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IongitudinaI muscIe (the tenia coli above and the compIete Iongitudinai muscIe sheath of the rectum beIow, which forms a cyIindrica1 tendon and joins the externaf sphincter ani at the fibromuscuIar insertion of the Ievatores ani). The contraction of the IongitudinaI fibers and consequent shortening of the rectum by the Ievatores ani, combined with the simultaneous onset of peristaIsis, accompanied by a coijrdinate reIaxation of the ana sphincters, resuIts in the evacuation of the feces. Faiiing this, as AIvarez,l* Hurst,l” and others have pointed out, the individua1 wiI1 have of headache, furred pressure, symptoms tongue, fou1 breath, malaise, menta1 sfuggishness, etc. The use of minera oi1 as a Iaxative is open to severe criticism on the grounds that it destroys the normai physioIogic processes outlined above. The competence of the rectosigmoid “vaIve” is destroyed and as a consequence the reservoir effect of the more proximal bowe1 is Iost. Continua1 Ieakage from above resuIts in the rectum being kept partiaIIy fuI1 most of the time and causes its conversion into an abnorma1 receptacIe for feca1 materia1. The mere presence of Iiquid petrolatum in the rectum does not initiate any urge for defecation by establishment of the might be reff ex. If it did the patient better off, for he wouId be caIIed upon to have a bowel movement and to rid himseIf of the dirty, oiiy feces. As suggested above there is not sufficient pressure to initiate the defecation reflex, but there is enough fecal materiaf present to cause symptoms of irritation. 2. When minera oi1 is present in the rectum compIete evacuation is impossibIe. Whatever the degree of emuIsification in the smaI1 intestine, one aIways finds a tenacious Iayer of a dirty mixture of oi1 and feces covering the recta1 mucosa. fn my practice as a proctoIogist, sigmoidoscopy is carried out on most of my patients and in those having taken Iiquid petrolatum one can nearly aIways discern the presence of the oi1 macroscopicaIIy; in which cases it is impossible to examine

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the recta1 waI1 properIy. This hoIds true whether the patient has or has not defecated prior to the examination. The dirty fiIm is wiped off with d&uIty and if any great pressure is used the mucosa bIeeds readiIy. Ordinary suction wiI1 not cIean the bowe1 waI1 and repeated enemas and coIon ffushings are necessary to accompIish proper visuaIization. 3. The use of minera oi1 was shown to be the cause of weight Ioss in chiIdren by TiII16 and Dutcher.l’ Jackson’* (in two different experiments) demonstrated delinite Ioss of weight and strength in animaIs which were given reguIar doses of minera oi1. He considered this to be due to the carrying away of the fat soIubIe vitamins A and D. Later, when the same animaIs were given the minera oi1 aIong with irradiated viostero1, they soon regained the Iost weight. Rowntreelg suggests the use of increased amounts of vitamins A and D in the food of patients who are given minera 0iI. InvaIids and chiIdren, who most frequentIy need more vitamins than usua1, are the very patients who are usuaIIy given minera oi1 by their physicians. Since I have been studying the cIinica1 effects of Iiquid petroIatum, I have found a number of patients who have suffered aIarming weight Ioss which seemed to be reIated to reguIar Iarge draughts from the minera oi1 bottIe. 4. MineraI oi1, whether or not it is in compIete emuIsion, hastens the motiIity of the bowe1 contents in the smaI1 intestine and as a consequence, digestion is incompIete. From Auoroscopic studies in cats, Lanczoz20 concIudes that minera oil cannot be regarded simpIy as a Iubricant. It hastened the passage of the contrast barium mea1 through the stomach and smaI1 intestine and visibly increased peristaIsis. The motiIity did not appear to be hastened in the Iarge intestine. Defecation was sometimes excited but this did not resuIt in compIete evacuation. The cIosure of the pyIorus by morphine* was weakened * Some authors do not agree that morphine contracting action on the pylorus.

has a

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or prevented by Iiquid petroIatum. He feIt that the Iaxative action of the oi1 was either (a) antispasmodic in preventing irritation; or (b) direct nervous stimuIation by a foreign substance. 5. There is cIinica1 evidence that individuaIs who have taken oi1 over a Iong period of time suffer from “indigestion.” This is perhaps due in Iarge measure to interference with absorption from the smaI1 intestine. It is suggested that the oi1, by partiaIIy covering over the estimated IO square meters of surface area (Best and TayIor) and its miIIions of viIIi, as we11 as by interference of the action of the digestive ferments on ingested food, estabIishes a mechanica barrier to absorption and digesti0n.t Spriggs21 and his coIIeague Leigh hoId the opinion that minera oi1 does not interfere with absorption. In two patients they made three day tests in which ingested food and paraffin were weighed. OnIy 4 per cent and 5 per cent respectiveIy of the food eIements were recovered in the feces. Varying quantities of the paraffin were recovered (i.e., I I per cent and 17 per cent). According to the figures submitted, the patient taking the smaIIer amount of oi1 excreted the Their observations are Iarger quantity. scarceIy concIusive. There is no evidence to show that minera oi1 interferes with secretion of the mucous gIands. ProbabIy is true, the the opposite (i.e., stimukition) hydrocarbon oi1 evidentIy producing chemica1 irritation as a foreign body. PATHOLOGIC

CONSIDERATIONS

6. MineraI oi1 shouId never be given before or after operations on the rectum. One wouId never think of using oi1 sprays folIowing nose or throat operations because of the danger of hemorrhage and the interference with heaIing, and yet many surgeons advocate Iarge doses of oi1 before t The actua1 occlusion df the ducts has never been demonstrated, and SchIagintweit,g after observing rats which had been given smal1 doses of oiI, says that coating of the intestina1 mucosa which would prevent resorption does not take place.

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and after recta1 operations. Within the past month I have been caIIed in cons&ation in two cases of postoperative hemorrhage foIIowing hemorrhoidectomy. Both patients had had severa transfusions and both had had minera oiI twice daiIy. The discontinuance of the oi1, repeated norma saIine flushings aIong with tannic acid instiIIations and more transfusions, ended the hemorrhages, but did not circumvent the consequent miId strictures which Iater needed surgica1 intervention. Most recta1 wounds are best Ieft to hea by granuIation and if they are of the proper shape and are kept cIean the resuIts wiI1 be good. MineraI oi1 interferes with proper hygiene and thereby causes discomfort. Patients who have been subject to frequent recta1 hemorrhages from interna hemorrhoids are seIdom reIieved by taking mineral oi1. The stooIs are softer and cause Iess trauma, but oftentimes there is more bIeeding than ever. A uroIogist, in a persona communication, teIIs me that after performing an interna urethrotomy for stricture he aIways uses steriIe minera oi1 to prevent rapid heaIing. Carr and Johnson22 have caIIed attention to the fact that varying amounts of oil or fat in the bIood stream may cause death by fat emboIism. In their case 50 cc. of steriIe cotton seed oi1 was injected into the posterior urethra in order to faciIitate catheterization. The urethra1 mucous membrane had been traumatized from previous attempts to pass a bougie through a stricture. The patient died shortIy afterward from oi1 emboIi in the basiIar artery, kidneys and Iungs. The administration of oi1 by mouth or by recta1 instiIIation foIIowing recta1 operation may therefore, apart from the danger of hemorrhage, carry some risk. In those cases of emboIic death after hemorrhoidectomy in which no satisfactory expIanation of the origin of the emboIus is forthcoming to expIain the accident, oi1 emboIism is a factor to be considered. 7. The use of minera oiI is often an indirect cause of pruritus ani. The definite

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Ieakage from the anus in those patients who take oi1 interferes with proper ana hygiene. The deIicate periana1 skin (nowhere on the surface of the body is the skin more vuInerabIe) requires carefu1 attention. It needs to be kept cIean and dry. Pruritus wiI1 often persist in spite of adequate treatment if the patient continues to take minera oi1. Most patients with pruritus have IocaI recta1 Iesions and even if these are eradicated, cure wiI1 not ensue if the use of oil is continued. Gibbon23 reports a case of carcinoma of the scrotum which deveIoped during the course of treatment. His patient had a periana1 dermatitis which was due to Ieakage of oil onto the skin, the dermatitis finaIIy deveIoping into a surface carcinoma of the scrota1 epitheIium. 8. Channon and CoIIinson24 proved that oi1 is absorbed from the gut and that it appeared in the Iivers of rats and pigs. They noted an increase of non-saponifiable fats in these organs when the animaIs were fed on a synthetic diet containing medicina1 Iiquid paraffin. Their resuIts are opposed to those of MeIIanby25 (1927) who injected paraffin into the duodenum and was unabIe to recover any oi1 in the materia1 which was absorbed through the IacteaIs in the exmesentery. Ch annon and CoIIinson pIained this by drawing attention to the fact that their own paraffin differed chemicaIIy from that used by MeIIanby. Twort and Twort26 found definite pathoIogic Iiver changes in many thousands of mice in which minera oil had been used on the skin in the study of carcinogenic agents. The Iivers of these animaIs were demonstrated to have vacuoIization with uItimate fatty i&Itration and partia1 Iiver destruction. SimiIar changes occurred in the spIeen, suprarena1 gIands and the ovaries. In these animaIs the portaIs of entry into the viscera couId we11 have been through the skin. The authors however expIained the pathoIogic changes as being due to the animaIs ingesting the oi1 by Iicking their wounds and beIieved that

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the oiI entered the various organs as the resuIt of normaI absorption from the digestive tract. The observations of Twort and Twort are rendered much more significant by the findings of Tantini.2’ This author fed minera oi1 to rats which then deveIoped true oi1 granulomata and definite fatty degeneration and destruction of the Iiver ceIIs. In another experimenP the same author made repeated intraperitonea1 injections of oi1 in guinea pigs which a11 demonstrated true neopIastic transformation. The minera oi1 “infXtrated the iiver abundantIy ” and caused fatty degeneration and other regressive processes. In both experiments the histochemica1 differentiation of minera oi1 and fat in the hepatic ceIIs and in the parafinomata were demonstrated by the method of Carminati.2g SUMMARY

A. Physiologic Considerations. I. Minera1 oi1 Iubricates the rectosigmoid and makes a reservoir of the rectum. 2. MineraI oi1 makes compIete evacuation impossibIe. 3. MineraI oi1 has a very deIeterious effect on the nutritiona economy of fat soIubIe vitamins. 4. MineraI oi1 hastens the motiIity of the bowe1 contents and thereby prevents compIete digestion. 5. MineraI oi1 may interfere with the throughout the of absorption process bowe1. B. Pathologic Considerations. 6. Minera1 oi1 interferes with the heaIing of postoperative wounds in the anorecta1 region and may induce hemorrhage. 7. MineraI oi1 is often the indirect cause of pruritus ani. 8. Evidence is accumuIating that minera1 oi1 may be absorbed, producing pathoIogic changes in the Iiver and other abdomina1 viscera.

NOVEMBER. ,938

Oil CONCLUSIONS

The interna administration of minera oi1, either aIone or in combination with other substances, may be attended by decided disadvantages. In view of the Iightheartedness with which minera oi1 has been prescribed as a Iaxative, I fee1 that this discussion is timeIy. It is onIy proper to state that any discussion of minera oi1 as a carcinogenic agent or as a factor in producing puImonary oIeomata is not within the scope of this paper. REFERENCES I. RANDOLPH, N. A. Tberap. Gaz., g: 732, 1885. 2. ROBINSON. Ouoted bv SolImam6 3. LANE, ARB&NOT. Practitioner, 92: 92-301, 1914. PharmacoIogy. Phila., 1929. 4. CLARK. Applied BIakiston, p. 250. PhiIa., 1905. Lippin5. WOOD, H. C. Therapeutics. cott, p. 674. 6. SOLLMAN. Manual of PharmacoIogy. 1936, p. 132. 7. BASTEDO, W. A. J. A. M. A., 60: 808, 1915. 8. NEWMAN and GRUENFELD.J. Missouri State M. A., 4: 162, 1929. 9. SCHLAGINTWEIT,E. Arch f. Exper. Path. u. Pbarmakol., 124: 59, 1927. IO. LOEWE, S. Klin. Wcbnscbr., 8: 1950, 1929. II. SCHWARTZ. Klinische Roentgen Diagnostik des DBnndarmes. Berlin, 1914. 12. HOLTZKNECHT. Quoted by BARCLAY, A. E. Lancet 1: II, 1934. ‘3. BEST and TAYLOR. PhysioIogicaI Basis of MedicaI Practice. Baltimore 1937. Wm. Wood, p. 796. 14. ALVAREZ,W. The Mechanics of the Digestive Tract. New York, 1928. Heineman. 15. HURST, A. F. Constipation, etc. Oxford Med. Pub. ‘919.

16. TILL. J. State Med., 42: 363 1934. 17. DUTCHER, R. J. Nutrition, 8: 269, 1934. 18. JACKSON.J. Nutrition, 7: 607-622, 1934.

19. KOUNTREE, J. J. Nutrition, 3: 345, 1931. 20. LANCZOZ, Z. Arch. Exper. Patb. u. Pbarmakol., I 12: 365, 1926. 21. SPRIGGS, E. I. Lancet, 1930, p. 992. 22. CARR and JOHNSON,J. A. M. A., 106: 1973, 1935. 23. GIBSON, R. Brit. M. J., I: 876, 1927. 24. CHANNON and COLLINSON. J. Biocbem., 23: 676 25. 26. 27. 28. 29.

1929. MELLANBY. J. Pbysiol., 64: Proc. v, XXXIII, 1927. TWORT and TWORT. Lancet, I : 448, 1932. TANTINI, E. Tumori, 21: 266, ,935. __ TANTINI, E. Arch. inst. biocbem. ital., I: 27, 1935. CARMINATI. Lo Spermentale, 4: 564, 1934.