Rectal preparations enemas

The active ingredient in the rectal suspension enema, a disposable (60 mL) unit, is mesalamine, also known as 5-aminosalicylic acid. Each rectal suspension enema unit contains 4 g of mesalamine. In addition to mesalamine, the preparation contains the inactive ingredients carbomer 934P, edetate disodium, potassium acetate, potassium met-... 

Each rectal suspension enema unit contains 4 g of mesalamine. In addition to mesalamine, the preparation contains the inactive ingredients carbomer 934P, edetate... 

Enema A rectal preparation for therapeutic, diagnostic, or nutritive purposes. 

Other semi-liquid or liquid preparations can be used rectally (gel, enemas). Rectal drug delivery should not be overlooked in certain therapeutic situations, when oral and parenteral routes are not available, or when the child is unconscious (e.g. postoperative), vomiting or on continuous suction. The absorption is usually rapid and may avoid first-pass metabolism. 

Microbiological stability may be a problem too. Aqueous enemas are prone to microbiological contamination and growth. The Ph. Eur. sets the same requirements for TAMC and TYMC (see Sect. 19.6.3) to rectal preparations as to oral preparations (10 CFU/g or mL, see Sect. 19.6.2). Enemas, like oral mixtures, should also meet with the requirements of preservation efficacy. For preservatives reference is made to Sect. 23.8. Generally methyl parahydroxybenzoate 0.15 % is used. 

Containers for liquid rectal preparations range in volume from several millilitres to approximately 100 mL. The container must be equipped with a rectal cannula to administer the enema. Enemas can be packaged in enema bags (see Sect. 24.4.13.2). These have a longer cannula with which the enema can be administered deeper into the rectum. Another possibility is to package an enema in a syringe on which a rectal cannula is placed (see Sect. 24.4.16). 

Administration of liquid rectal preparations requires a squeezable bottle (see Sect. 24.4.4.1), a bag (Sect. 24.4.13.2) or a syringe (see Sect. 24.4.16), with a rectal cannula (see Fig. 24.10). This cannula is preferably of flexible material to prevent damage to the rectal mucosa. This is less important with short cannulas than with long ones. An enema bag has a long flexible tube cannula. This cannula should be lubricated or should be made of slippery material to ease insertion. The cannula should have a rubber one-way check valve when respiration is possible (with enema bottles, not with enema bags). 

Rectal administration The drug is also administered rectally in the form of suppositories and enema preparations which are absorbed from the colon. 

Aphthous ulcers in the rectal mucosa have been reported in association with the use of Fleet-phospho-soda enema in preparation for colonoscopy in a 54-year-old woman (43). 

Enemas commonly are employed either by themselves or as adjuncts to bowel preparation regimens to empty the distal colon or rectum of retained solid material. Bowel distention by any means will produce an evacuation reflex in most people, and almost any form of enema, including normal saline solution, can achieve this. Specialized enemas contain additional substances that either are osmoticaUy active or irritant however, their safety and efficacy have not been studied in a rigorous manner. Repeated enemas with tap water or other hypotonic solutions can cause hyponatremia repeated enemas with sodium phosphate-containing solution can cause hypocalcemia. Phosphate-containing enemas also are known to alter the appearance of rectal mucosa. 

Most treatments in ruminants require the addition of calcium to the magnesium salts to correct the hypocalcemia that is commonly observed in these animals. Magnesium enemas have also been used [86]. Injectable or rectally administered magnesium is then followed by the use of oral magnesium preparations until the Mg levels have stabilized and the underlying cause has been corrected. 

For rectal administration an active substance can be formulated into a suppository (solid dosage form) or in an enema (liquid dosage form). The desired miset of action is important for the choice. For a rapid onset an enema is preferable, because a suppository base has to melt or to dissolve first. A suppository may be preferred because its use is easier and more patient-friendly. An enema is the best choice when a local effect over a large surface is desired, for instance in the treatment of ulcerative colitis. From a practical viewpoint an enema can be prepared faster, but is more sensitive to chemical degradation, due to the presence of water. 

Vaginal foams Medicated vaginal tampons From the rectal dosage forms the suppositories, enemas, ointments and creams are important as extemporaneous pharmacy preparations from the vaginal dosage forms fliese are the vaginal suppositories (pessaries), solutions, creams and gels. 

Dexamethasone, prednisolone and hydrocortisone are systemically active via the rectal route. The best chemical form of the active substance must be chosen and a dosage form that provides good release of the active substance. A corticosteroid as salt in solution is often optimal for an enema and the preparation is easy. As a solution in water it avoids problems such as release from a fatty base and subsequent dissolution. Dexamethasone and prednisolone for instance are used as sodium phosphate salts. Conversion and factorisation must not be forgotten. For stability reasons... 

Some suspensions have such a limited stability, that they have to be prepared just before use. An example is an enema with budesonide, where the active substance is incorporated in a dispersible tablet, that has to be added to a solution for rectal suspension. Here again, correct instruction of the user or caregiver is important. 

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