Liquid paraffin: a reappraisal of its role in the treatment of constipation.

Liquid paraYn or mineral oil is a transparent, colourless, odourless, or almost odourless, oily liquid composed of saturated hydrocarbons obtained from petroleum. Petroleum was used as a medicine at least 400 years before Christ. The earliest internal use of refined petroleum appears to date back to 1872, when Robert A. Chesebrough was granted a patent for the manufacture of “a new and useful product from petroleum”. The use of liquid paraYn gained popularity, after Sir W. Arbuthnot Lane, Chief Surgeon of Guy’s Hospital in 1913, recommended its use as a treatment for intestinal stasis and chronic constipation. The popularity of liquid paraYn as a treatment for constipation and encopresis stems primarily from its tolerability and ease of titration. Although conversion of mineral oil to hydroxy fatty acids induces an osmotic eVect, liquid paraYn appears to work primarily as a stool lubricant. Therefore, liquid paraYn is not associated with abdominal cramps, diarrhoea, flatulence, electrolyte disturbances, or the emergence of tolerance with long term usage, side eVects commonly associated with osmotic or stimulant laxatives. These features make liquid paraYn particularly attractive for use in chronic constipation and encopresis of childhood, where large doses and prolonged administration commonly are necessary during the disimpaction and maintenance phases of treatment, respectively. However, although liquid paraYn is widely accepted and recommended as a fundamental component of regimens for the management of constipation in North America and Australia, 7 it is little used in the United Kingdom. 9 This trans-Atlantic dichotomy in liquid paraYn usage has been underscored by the American Academy of Pediatrics (AAP) endorsement of practice guidelines developed by the North American Society for Pediatric Gastroenterology and Nutrition (NASPGN) for the management of constipation in infants and children. NASPGN clearly identify liquid paraYn (mineral oil) as a medication of first choice in the management of paediatric constipation. Therefore, it is timely to reappraise the role of liquid paraYn in the management of childhood constipation and to explore the reasons underlying local distrust of this medication. Approach to childhood constipation Functional constipation is one of the most common conditions treated by paediatric gastroenterologists and general paediatricians. Recommendations for management have varied from dietary manipulation, administration of lubricants, osmotic agents, stimulants, or enemas, to toilet regimens, psychotherapy, and biofeedback programmes. It has been reported that over half of children with constipation remain chronically constipated if they do not receive frequent doses of laxative. The pathophysiological basis of functional constipation is uncertain. Currently, most widely used treatment regimens for childhood constipation and encopresis 7 are modelled on the strategy described by Davidson and colleagues in 1963. This seminal paper outlines three phases in the management of children with constipation: complete evacuation or disimpaction; sustained evacuation to restore normal colorectal tone; and long term follow up with weaning from intervention. As the success of each phase depends on the cooperation and understanding of the parent and, when possible, the child, an initial phase of patient and parent education has been incorporated into recent guidelines. 6 16 Complete bowel clean out is the cornerstone of successful therapy prior to implementation of long term pharmacological therapy. Once rectal evacuation has been confirmed, the challenge is to keep the rectum empty. This is accomplished by habitual toilet use, and the use of stool softeners to facilitate daily complete evacuation. This phase can last at least six months. The aim of this and the follow up phase is to restore normal bowel habit. Although a period of successful maintenance treatment may be followed by attempts to wean medication, close medical/nursing supervision is essential in order to promptly adjust or reinstitute doses, when necessary.