The Safety & Efficacy of Suppository Use

An in-depth discussion on the expanded utility of suppositories in clinical pharmacy practice was the main thrust of a roundtable held in Seattle, Washington on November 12, 1998. Educational funding for this event was underwritten by G&W Laboratories, Inc. An overview of current and future suppository applications was provided by Edgar R. Gonzalez, Pharm.D., FASHP, FASCP, Associate Professor of Pharmacy and Emergency Medicine, Virginia Commonwealth University, Richmond, VA. The roundtable was comprised of five pharmacists from various practice settings and was moderated by Angele C. D'Angelo, Editor-in-Chief of U.S. Pharmacist. This article provides a synopsis of Dr. Gonzalez's presentation as well as highlights of the dialogue from the roundtable panelists.

INTRODUCTION

Suppositories are a very feasible route of administration for medication. The presumed vanity of Americans has seemingly deterred healthcare professionals in the United States from using suppositories more frequently as a means of delivering medications. In contrast, most Europeans have no qualms about using suppositories. It is well recognized that over-the-counter therapy with suppositories is an enormously large market. Healthcare professionals and patients alike can easily find astringent OTCs for hemorrhoids, anti-pruritics, antiseptics, emollients, and vasoconstrictors that are available in suppository form. The fact that this market is growing indicates that Americans are willing to utilize suppositories. The term suppository comes from Latin and means "to place under." Three types of suppositories are available: rectal, vaginal, and urethral. It is thought that suppositories were first used in nursing facilities to be administered to elderly patients who were not capable of receiving medications through more traditional delivery systems. Nurses played a large role in promoting the use of suppositories, due to their preference in using them rather than injecting elderly patients via the IV route.

USES TODAY

Within the era of cost-containment and the risk of AIDS and other communicable blood-borne diseases, suppository drug delivery is becoming a more viable option for pharmacists and nurses, since suppositories provide direct access to the systemic circulation, efficiently bypassing the portal circulation and the liver metabolism on the first pass. It is a little known fact that the lower and middle hemorrhoidal veins bypass the liver and do not undergo first-pass metabolism. Therefore, suppositories can deliver the drug rapidly to the lower and middle hemorrhoidal veins for absorption. The rectum is an interesting area for drug absorption because it is not buffered and has a neutral pH. It also has very little enzymatic activity, thus enzymatic degradation does not occur. The rectal mucosa is more capable than the gastric mucosa of tolerating various drug-elated irritations. This is especially important in patients with gastric disease. The anal-rectal physiology provides a large surface area for drug absorption. The surface area is also permeable to non-ionized drugs. Suppository formulations are rather efficient in delivering medications because they do not occupy much volume. Another factor that is important in drug delivery is drug solubility. Suppositories can be used with a variety of different bases to increase absorption and reduce complications. Drug concentration is another factor to consider when deciding to use suppositories. The osmosis process allows the drug to transfer from the vehicle in the suppository, across the membrane of the rectum, and into the hemorrhoidal veins. The higher the concentration and the greater the solubility, the more efficient is the transfer of medication. As we become more aware of the potential complications of infection associated with the use of IVs, suppository administration provides a preferable alternative. Suppositories have been shown to be a safe and efficacious way to deliver medications, particularly in emergency situations. Packaging issues are important to consider. Storage, especially refrigeration, can be a problem. Placing the suppository at room temperature one-half hour before administration can make the suppository a bit more pliable. Glycerine suppositories should be stored in moisture-resistant glass containers or polyurethane jars, or be foil-wrapped, whereas polyethylene glycol suppositories do not need to be maintained in specific storage containers. Vaginal suppositories continue to be used frequently, especially for treatment of vaginal candidiasis or yeast infections. Urethral suppositories are also being used for erectile dysfunction. In addition, suppositories are being used for individuals with UTIs and prostatitis. These work because suppositories deliver the drug nearer to the site of activity. Studies are currently underway to evaluate future uses of suppositories as drug delivery mechanisms. Suppositories are being explored to deliver hypoglycemic agents to diabetic patients with diabetic gastroparesis and to deliver medication to patients with poorly controlled Parkinson's disease.

THE ROLE OF THE PHARMACIST

Pharmacists need to become more creative in how to deliver drugs to patients. Pharmacists need to concentrate on how to make drug delivery more convenient in nursing facilities and institutionalized care settings. One important factor is determining whether or not a patient can self-administer a suppository. You would need to know what obstacles are present that could hamper their ability to use suppositories. In addition, counseling may be required to educate patients on proper suppository administration. There appears to be relatively good acceptance by consumers for suppository administration, especially if one conveys to them the value of the drug delivery system, and if one formulates the preparation in a manner in which it can be given once or twice a day. Suppositories are certainly a type of delivery system the patient is willing to use. The largest myth surrounding suppository use is that you only give suppositories to patients who cannot swallow. We should be looking at suppositories as a convenient drug delivery system, even with patients who can swallow, because certain drugs are better handled by bypassing first-pass metabolism.

CONCLUSION

Rectal administration is yet to be truly explored as a potential for drug delivery in many institutional settings and non-institutional settings for drugs that are either too irritating to the gut or are more effective if not metabolized by the liver. For both scientific and economics reasons we should really consider rectal administration to be a viable and valuable option. Suppositories offer patients an option that is less invasive and less discomforting.