Tablets rectal administration

Taking broken, chewed, or crushed tablets could lead to the rapid release and absorption of a potentially fatal dose of oxycodone. OxyContin is not indicated for rectal administration. Data from a study involving 21 normal volunteers show that OxyContin tablets administered per rectum resulted in an AUC 39% greater and a Cmax... 

Rectal administration For outpatient treatment when oral dosing is not possible, suppositories containing 25 mg metoclopramide have been extemporaneously compounded (5 pulverized oral tablets in polyethylene glycol). Administer 1 suppository 30 to 60 minutes before each meal and at bedtime. 

Drugs may also be administered locally in the form of bougies, jellies for urethra, pessaries, vaginal tablets, creams and douches for vagina and suppositories for rectal administration. 

For some patients and with certain drugs, such as certain sedatives, oral administration may raise a concern with respect to the possibility of severe accidental or intentional overdosing. This danger is practically eliminated by rectal administration. Whereas it is relatively easy for a patient to swallow a number of tablets, it is much more difficult to administer numerous suppositories rectally at the same time. Thus rectal administration may be indicated for patients for whom overdosing is a significant concern. 

There are two main ways by which substances may be administered to humans the enteral and the parenteral routes. For enteral administration the substance is placed directly into the gastrointestinal tract by permitting a tablet to dissolve when it is placed under the tongue (sub-lingual administration), or by swallowing a tablet, capsule or a solution (oral) or by rectal administration as a suppository. In parenteral administration the substance in solution may be injected subcutaneously, intramuscularly or intravascularly, inhaled as an aerosol, applied topically to the skin as a cream or ointment, or, rarely, in the form of a pessary. 

In clinical practice various oral dosage forms are also used for rectal administration. There is often little scientific support for such use, nevertheless it may be effective. Evidence exists for rectal administration of an oral controlled release morphine tablet (MS-Contin ) [2, 3]. Rectal use of temazepam oral capsules is not effective. There is a broad variation in time to reach the maximum plasma concentration and in the biological availability. Better outcomes are obtained with temazepam dissolved in glycofuroFethanol water = 5 1 4 and given rectally as an enema [4]. 

Walsh D, Tropiano PS (2002) Long-term rectal administration of high-dose sustained-release morphine tablets. Support Care Cancer 10 653-655... 

This model is representative for the conditions described in the previous section, except for the mode of administration which can be oral, rectal or parenteral by means of injection into muscle, fat, under the skin, etc. (Fig. 39.7). In addition to the central plasma compartment, the model involves an absorption compartment to which the drug is rapidly delivered. This may be to the gut in the case of tablets, syrups and suppositories or into adipose, muscle or skin tissues in the case of injections. The transport from the absorption site to the central compartment is assumed to be one-way and governed by the transfer constant (Fig. 39.7a). The linear differential model for this problem can be defined in the following way ... 

Opioids maybe administered in a variety of routes including oral (tablet and liquid), sublingual, rectal, transdermal, transmucosal, intravenous, subcutaneous, and intraspinal. While the oral and transdermal routes are most common, the method of administration is based on patient needs (severity of pain) and characteristics (swallowing difficulty and preference). Oral opioids have an onset of effect of 45 minutes, so intravenous or subcutaneous administration maybe preferred if more rapid relief is desired. Intramuscular injections are not recommended because of pain at the injection site and wide fluctuations in drug absorption and peak plasma concentrations achieved. More invasive routes of administration such as PCA and intraspinal (epidural and intrathecal) are primarily used postoperatively, but may also be used in refractory chronic pain situations. PCA delivers a self-administered dose via an infusion pump with a preprogrammed dose, minimum dosing interval, and maximum hourly dose. Morphine, fentanyl, and hydromorphone are commonly administered via PCA pumps by the intravenous route, but less frequently by the subcutaneous or epidural route. 

Drugs are administrated by intravenous routes or ex-travascular routes including oral, sublingual, subcutaneous, intramuscular, rectal (by enema or suppository), and transdermal. Available dosage forms include suspensions, immediate-release capsules or tablets, sustained-release capsules or tablets, and enteric-coated capsules or tablets that resist dissolution in the acidic pfi of the stomach. 

Tramadol is available as drops, capsules, and sustained-release formulations for oral use, suppositories for rectal use, and solution for intramuscular, intravenous, and subcutaneous injection. After oral administration, tramadol is rapidly and almost completely absorbed. Sustained-release tablets release the active ingredient over a period of 12 h, reach peak concentrations after 4.9 h, and have a bioavailability of 87 to 95% compared with capsules. One 100-mg dose given to healthy volunteers resulted in plasma levels of 375 ng/ml at 1.5 h.55 Tramadol is 20% bound to plasma protein and it is rapidly distributed in the body it is mainly metabolized by O- and A-demethylation forming glucuronides and sulfates that are excreted by the kidney. 

Codeine-containing medications are most often taken orally, either in tablet form or as syrup (also called elixir ). Codeine may also be given by intramuscular (IM) injection. Intravenous codeine administration is not used because of the risk of causing dangerously low blood pressure (hypotension). Codeine suppositories are given rectally, but usually only in infants and children who have had surgery. 

Multiple dosage formulations (oral tablet, oral liquid, rectal gel, injectable) allow more flexibility of administration compared to most other benzodiazepines... 

Morphine is available for oral, rectal, and parenteral administration. Oral formulations include immediate and controlled release tablets, as well as oral solution regular strength and concentrate. Parenterally, it can be administered subcutaneously, intramuscularly, intravenously, or by continuous infusion. It is a drug of abuse and can be nasally insufflated. 

The bioavailability of warfarin is nearly complete when the drug is administered orally, intravenously, or rectally. Different commercial preparations of warfarin tablets vary in their rate of dissolution, and this causes some variation in the rate and extent of absorption. Food in the GI tract also can decrease the rate of absorption. Warfarin usually is detectable in plasma within 1 hour of its oral administration, and concentrations peak in 2-8 hours. 

It is well absorbed after administration, which may be retarded in the presence of food. However, the rectal suppositories are absorbed slowly and very much erratically. The peak plasma levels for imcoated tablets and liquids are attained within a span of 2 hours the average volume of distribution stands at 0.5 L.kg A minimum of 10 to 20 meg. mL in plasma or serum levels is an absolute requirement to cause a maximum bronchodilator response. Generally, it exhibits relatively much more pharmacological response than theobromine in all aspects. 

Clearly, the formulation chosen for particular drugs is not random. Furthermore, the degree to which it is critical varies from drug to drug. For example, hydrocortisone is available for at least seven routes of administration, as tablets, several creams and ointments, intraocular solutions, suppositories, intra-rectal foams, injections, and eardrops. Even newer drugs, with fewer indications than hydrocortisone, seek greater market acceptability by providing a variety of alternative formulations (e.g. sumatriptan is available as an injection, intranasal spray, suppository, and tablets). 

An intramuscular injection with a licensed pharmaceutical preparation that contains hydrocortisone sodium succinate would constitute a major treatment option. However, the child s parents do not want to give an injection to their child. Klaartje drinks very reluctantly as all babies with the Trader Willi syndrome. The parents don t consider administration with the feeding of the contents of a capsule or of crushed tablets as a reliable option. Therefore, the doctor has suggested a rectal preparation. 

---