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PubMedDate not supplied

Pharmacokinetics and therapeutic study with nimesulide suppositories in children with post-operative pain and inflammation.

The pharmacokinetic pattern of 100 mg nimesulide administered rectally at different times prior to undergoing minor surgery was studied in 45 children. Absorption of nimesulide was relatively fast, a peak plasma concentration of 75 mg/l being reached 3 h after administration, and the elimination half-life was 3.15 h. The efficacy and tolerability of the nimesulide suppositories were assessed in a randomized, double-blind, dipyrone-controlled study of 50 children suffering from moderate to severe post-operative pain, the drugs being administered one to three times daily as required; 26 patients received nimesulide and 24 dipyrone. A consistent reduction in pain was recorded during nimesulide therapy given for a mean period of 2.5 days, with a mean consumption of 3.5 suppositories. Similar results were obtained in dipyrone-treated patients. The efficacy of both drugs was judged by the physicians to be good or very good in 70% of cases and there were no statistically significant differences between the two treatment groups in the dosage required or the pain relief. Tolerability of both drugs was excellent, with only one patient in each treatment group complaining of nausea.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

[Pharmacologic basis for using paracetamol: pharmacokinetic and pharmacodynamic issues].

The advantage of paracetamol (acetaminophen) is that it can be administered via the oral, intravenous or rectal routes. The last mentioned differs from the oral route in the slow and irregular absorption of the active substance. At therapeutic concentrations, the pharmacokinetics of paracetamol are linear--that is, independent of the dose, and constant with repeated administration. The efficacy of paracetamol has been demonstrated in a wide variety of acute or chronic painful syndromes. In adults, the optimum unit dose is 1 g. The maximum daily dosage is 4 g, consistent with the decline in analgesic activity, which is usually over 6 hours. With effervescent tablets, drug absorption and onset of action are more rapid than with conventional tablets. However, there is no direct correlation between serum concentrations of paracetamol and its analgesic or antipyretic effect. Paracetamol is the non-opiate analgesic of choice in elderly persons or patients with chronic renal insufficiency, and it is usually not necessary to reduce the dosage in such individuals, even though clearance is reduced. Although the bioavailability of paracetamol is not impaired in patients with chronic, benign liver diseases, the agent is contraindicated in those with hepatic insufficiency. It can be used during pregnancy and lactation. The very low level of paracetamol binding to plasma proteins, together with its hepatic metabolism, mainly through glucuronide or sulphate conjugation, account for the low risk of drug interactions with paracetamol, particularly with antivitamin K. When added to a traditional non-steroidal anti-inflammatory drug, paracetamol enhances the analgesic effect or allows the use of lower doses. It is more difficult to define the ideal dosage of paracetamol in children, because of the influence of age on its pharmacokinetics, and the relatively erratic bioavailability of suppositories. An oral dose of 15 mg/kg every 4 hours, up to a total of 60 mg/kg/day, is usually sufficient to achieve the desired analgesic or antipyretic effect.

Acetaminophen↗
PubMed1980

The effect of cathartic agents on transmucosal electrical potential difference in the human rectum.

Active ion transport in the colon is generating a transmucosal electrical potential difference (PD) of about 40 mV. Cathartic agents inhibit electrolyte and water net-absorption or cause net-secretion which should be reflected in a change of PD. In 83 normal subjects the effect of an isotonic eletrolyte solution (control) and different cathartic agents on rectal PD was tested: Laxatives (bisacodyl, rhein), bile acids (cholic and deoxycholic acid), fatty acids (oleic and ricinoleic acid) and cardiac glycosides (meproscillarin, digitoxin, digoxin). Bisacodyl, deoxycholic acid in high concentration, meproscillarin and digitoxin significantly decreased PD, while the other substances did not. Cathartics act on different transport mechanisms which together with different absorption characteristics of the proximal and distal colon may explain the difference in effecting the PD. Rectal PD measurement provides an easy and convenient tool to document effects of cathartic agents on electrolyte transport, otherwise difficult to obtain, and is applicable for clinical use.

Adult↗
PubMed1989

[Midazolam for premedication of infants. A comparison of the effect between oral and rectal administration].

Midazolam (M) has been successfully used in oral and rectal premedication of children of one to six years of age. The following study was designed to investigate the efficacy of both methods when used as premedication "on demand". 60 children (1-6 years) were randomly assigned to 0.3 mg/kg bw M orally and 0.5 mg/kg bw M rectally. Psychological, behavioural and physiological parameters were measured at special time intervals and special stressful events (separation from the mother or father, induction of anaesthesia). Rectally premedicated children were found to be better prepared concerning psychological and behavioural parameters. This can be due to the dosage as well as the faster absorption of M. In the postoperative period orally premedicated children experienced significantly more nausea and vomiting. This might be due to the preparation with saccharin, peppermint oil and ethanol. - In "premedication on demand" rectal Midazolam must be preferred to orally administered Midazolam in the preparation mentioned above.

Administration, Oral↗
PubMed2003

Molecular and functional studies of electrogenic Na(+) transport in the distal colon and rectum of young and elderly subjects.

BACKGROUND: Human distal nephron and distal colon both exhibit mineralocorticoid sensitive electrogenic Na(+) absorption and make significant contributions to Na(+) homeostasis. Na(+) resorption in the distal nephron diminishes with age but it is unclear whether a similar change occurs in the distal colon. AIMS: To evaluate the effect of age on expression of apical Na(+) channels and basolateral Na(+), K(+)-ATPase, and on the responsiveness of electrogenic Na(+) absorption to mineralocorticoid stimulation in human distal colon and rectum. MATERIALS AND METHODS: Mucosal biopsies were obtained from healthy sigmoid colon and proximal rectum in "young" (aged 20-40 years) and "old" (aged 70 years or over) patients during routine colonoscopy/flexible sigmoidoscopy. Na(+) channel subunits and Na(+), K(+)-ATPase isoforms were studied at the mRNA level by in situ hybridisation and northern blotting, and at the protein level by immunocytochemistry and western blotting. The mineralocorticoid responsiveness of electrogenic Na(+) absorption was evaluated in the two groups by measuring amiloride sensitive electrical potential difference (PD) in the proximal rectum before and 24 hours after oral administration of 1 mg of fludrocortisone. RESULTS: Na(+) channel subunit and Na(+), K(+)-ATPase isoform expression at the level of mRNA and protein was similar in "young" and "old" patients. Both basal and the fludrocortisone stimulated amiloride sensitive rectal PDs were similar in the two groups. CONCLUSIONS: In contrast with the distal nephron, mineralocorticoid sensitive electrogenic Na(+) absorption in the human distal colon does not diminish with age, and may be particularly important in maintaining Na(+) homeostasis in the elderly.

Absorption↗
PubMed1991

Age dependence of erythromycin rectal bioavailability in children.

Erythromycin pharmacokinetics was studied in neonates (less than 1 month), infants (1-12 months) and other children (1-12 years) after the drug rectal and intravenous administration. The areas under the erythromycin serum concentration-time curves (AUC) were practically independent on children's age following the intravenous drug administration, but not its rectal administration. There was a distinct age dependency of the AUC parameter in the latter case. The increase of children's age was resulted in enhancement of the erythromycin total clearance, reduction of the steady-state volume of distribution and of the mean residence time. The extent of absolute bioavailability of rectally administered erythromycin was increased from 28 per cent in neonates to 36 per cent in infants and to 54 per cent in children greater than 1 year. Alteration of the mean absorption time parameter was reflected the delayed absorption of erythromycin in neonates.

Administration, Rectal↗
PubMedDate not supplied

End-tidal CO2, CO2 production, and O2 consumption as early indicators of approaching hyperthermia.

To illustrate the abilities of several physiologic events to indicate a change in metabolic status, dinitrophenol was used to induce hyperthermia. Ten dogs were divided into two groups, one being mechanically ventilated and the other allowed to breathe spontaneously. End-tidal CO2 (ETCO2) and CO2 production, O2 consumption, mean blood pressure, and rectal temperature were monitored continuously in both groups. Respired volume was measured with a pneumotachograph. An infrared-absorption CO2 analyzer measured inspired and expired CO2 concentrations. An ultraviolet-absorption analyzer measured inspired and expired O2 concentrations. Of the physiologic events measured, CO2 production and O2 consumption were the earliest and most reliable indicators of increased metabolism and consequent approaching hyperthermia in the spontaneously breathing and mechanically ventilated animals. In the spontaneously breathing animals ETCO2 transiently decreased due to transient tachypnea. In the mechanically ventilated animals ETCO2 increased steadily. Mean blood pressure increased more in the mechanically ventilated animals than in the spontaneously breathing animals. The increase in rectal temperature required 6 minutes or more to occur, whereas the increases in CO2 production and O2 consumption appeared in only about 2 minutes. It is concluded that ETCO2 is a reliable indicator of increased metabolism in mechanically ventilated subjects only, but CO2 production and O2 consumption are excellent indicators of increasing metabolism in spontaneously breathing and mechanically ventilated subjects.

Animals↗
PubMed2006

Misoprostol administered by epithelial routes: Drug absorption and uterine response.

OBJECTIVE: To quantify and compare serum levels and uterine effects following vaginal (dry), vaginal (moistened), buccal, and rectal misoprostol administration. METHODS: Forty women seeking elective abortion between 6 and 12 6/7 weeks were randomly assigned to receive 400 mug of misoprostol by one of four routes. A 2.5-mm pressure monitoring catheter was placed through the cervix to the uterine fundus to record uterine tone and activity during the 5-hour observation period. Serum levels of misoprostol acid were measured at 15 and 30 minutes, then every 30 minutes. RESULTS: The four groups were similar in age, race or ethnicity, body mass index, parity, and gestation. Serum levels after vaginal, vaginal moistened and buccal administration rose gradually, peaked between 15 and 120 minutes and fell slowly. Vaginal and vaginal moistened routes produced higher peak serum levels than buccal and rectal (445.9 and 427.1 compared with 264.8 and 202.2 pg/mL; P = .03) and higher serum concentration area under the curve at 5 hours (1,025.0 and 1279.4 compared with 519.6 and 312.5 pg-hr/mL; P < .001). Uterine tone and activity, however, were similar for buccal and the two vaginal routes. After rectal administration, serum levels peaked earlier (P < .001) then dropped more abruptly, and peak uterine tone (P < .001) and total activity (P = .04) were lower than after the other routes. CONCLUSION: Although serum levels were lower for buccal compared with the vaginal routes, the three routes produced similar uterine tone and activity. Rectal administration produced lower uterine tone and activity. Vaginal serum levels were two to three and a half times higher than those observed in prior misoprostol pharmacokinetic studies.

Abortifacient Agents, Nonsteroidal↗
PubMed1991

The protection of insulin against proteolytic processes after rectal application to normoglycemic rabbits.

In order to improve the bioavailability of insulin after rectal application to rabbits, the influence of surface-active amino acid-fatty acid condensate on absorption and, the effects of a protease inhibitor (aprotinine), of a disinfectant (methyl-hydroxybenzoate) and of chemotherapeutics (chloramphenicol, ambazone and metronidazole) were investigated. Only the application of methylhydroxybenzoate, ambazone and of metronidazole, which inhibit the anaerobic bacterial flora, improved bioavailability significantly. The examinations show that the proteolytic activity of the anaerobic bacterial flora causes the loss of the biological activity of peptides in the rectum.

Administration, Rectal↗
PubMed1971

Absorption of sodium and water by human rectum measured by a dialysis method.

A dialysis method for the study of intestinal absorption is described. Its use has been assessed in animals and normal human subjects and it has been applied to the measurement of rectal transport of sodium and water.When the luminal solution was of high sodium concentration (145 m-equiv/1), the sodium influx rate (lumen to plasma) was about five times greater than the sodium efflux rate (plasma to lumen). The luminal sodium concentration associated with zero net sodium flux was very low (<15 m-equiv/1). As the mucosa was charged with the luminal side negative, the epithelium must therefore possess a powerful sodium absorbing ;pump'. With isotonic solutions in the lumen, the amount of water absorbed depended on the sodium concentration and when this was 30 m-equiv/1 or less, no significant water absorption was detectable. When, however, water absorption was altered by imposing osmotic gradients, sodium absorption was not significantly affected. The luminal solution tended to become issomolar with plasma; osmotic gradients across the epithelium did not develop. The particular transport properties of rectal epithelium enabling it to remove sodium from the lumen against considerable electrochemical gradients are well adapted to its function.

Adult↗
PubMed1985

Rectal induction of anaesthesia in children with methohexitone. Patient acceptability and clinical pharmacokinetics.

Rectal induction of anaesthesia with 10% methohexitone 100 mg ml-1 was used in 50 healthy children, using a standard dose of 25 mg/kg body weight. The absorption of methohexitone was rapid and reliable: the children fell asleep within 10-15 min. The plasma concentration peaked at 10-15 min and then decayed rapidly. The terminal half-life of rectal methohexitone was 1-2 h. Overall patient acceptability was good, and there were no major complications.

Anesthesia, Rectal↗
PubMed1996

Systemic delivery of peptides and proteins across absorptive mucosae.

As therapeutic peptides and proteins become readily available through rapid advances in recombinant technology, and because rapid presystemic elimination renders them ineffective when administered orally, pharmaceutical scientists are faced with the challenge of delivering these macromolecules systemically; therefore, alternative routes of delivery need to be investigated. Transmucosal delivery through absorptive mucosae represents one of these alternatives. This route has the advantage of being noninvasive and of bypassing hepatogastrointestinal clearance. The absorptive mucosae that have been investigated for delivery of peptides and proteins include buccal, nasal, pulmonary, rectal, and vaginal. Nasal delivery has been studied extensively and has been the most successful--nasal sprays for buserelin, desmopressin, oxytocin, and calcitonin are already available commercially. In general, enzyme inhibitors and permeation enhancers need to be coadministered for successful delivery of these biopharmaceuticals. Classes of enhancers used for transmucosal delivery include bile salts, dihydrofusidates, cyclodextrins, surfactants, and chelating agents. Each of these agents exerts its enhancing effects by a different mechanism, and each has been associated with adverse effects. This article discusses the physiology of each of the mucosae used, the fundamentals of transmucosal delivery, and recent progress in systemic delivery of therapeutic peptides and proteins across each of the mucosae; in an effort to highlight principles of transmucosal delivery, it also discusses the transmucosal delivery of enkephalin, calcitonin, and insulin as case studies.

Absorption↗
PubMed1992

Magnetic resonance imaging of the gastrointestinal tract: investigation of baby milk as a low cost contrast medium.

After the incidental observation of the high signal intensity of the upper GI tract in a nourished baby, we tested eight baby milks; five different fresh commercial milks, one sweetened and condensed and two lyophilized milks in order to compare their ability to contrast MR images. The images were obtained with a 1.5 T magnet whereas the "in vitro" water proton relaxation time (T1 and T2) measurements were carried out at 0.5 T. After having selected the most effective lyophilized product, that was prepared according to the manufacturer's instructions, a group of 23 adult patients, 17 males and 6 females, with a mean age of 55.8 years (range 37 to 71 years) were examined. Thirteen patients had gastric cancer and ten patients had rectal or rectosigmoid junction tumors. The most effective imaging sequence was a spin-echo T1.w. After oral intake of milk a good contrast of the stomach, with sufficient distribution in the duodenum and the very proximal bowel, was achieved in all 13 patients with gastric cancer, as was a good depiction of the rectum and the recto-sigmoid junction after enema achieved in the 10 patients with rectal cancers. Disadvantages of lyophilized milk as a contrast agent are due to partial intestinal absorption, inhomogeneous distribution and irregular intestinal passage, whereas a clear advantage of lyophilized milk as a contrast agent is its good acceptance and palatable, inexpensive and non invasive properties. Because of these limitations lyophilized milk cannot be considered a real oral contrast medium but it can enhance MR imaging of the upper abdomen, and mainly of the lower GI tract in infants and adults.

Adult↗
PubMed1984

Disposition of ethanol and its effect on rectal temperature in morphine-dependent, morphine-abstinent and morphine-naive rats.

Rats were treated chronically with twice daily injections of morphine hydrochloride in gradually increasing doses from 20 to 200 mg/kg for 22 consecutive days. Rats in a control group were injected with 0.9% NaCl. At 1 hour after the last injection of morphine (dependent state) and at 3 and 16 days after abrupt withdrawal (abstinent state) the animals were injected intraperitoneally with 2.0 g/kg ethanol. Blood ethanol concentrations (tail blood) and rectal temperatures were determined at 30-60 min. intervals for up to 7 hours. The absorption of ethanol was slower in rats treated with morphine and the time taken to reach the end of the blood concentration curve was increased. This implies a slower turnover of ethanol in morphine-dependent and abstinent rats. At 16 days after withdrawal, the blood ethanol profiles were the same as in control rats not exposed to morphine. Injection of morphine (200 mg/kg) intolerant animals caused a pronounced hyperthermia which lasted for about 4 hours. Ethanol treatment rapidly counteracted the rise in body temperature. Morphine abstinent rats showed a hypothermic response to ethanol. The altered disposition of ethanol in acute withdrawal may result from physiological disturbances such as impaired fluid balance, dehydration, altered peripheral blood flow and poor nutritional status. There was no evidence for a faster rate of ethanol metabolism in the hypermetabolic state associated with morphine tolerance and dependence.

Animals↗
PubMed2004

Absorption pattern of trospium chloride along the human gastrointestinal tract assessed using local enteral administration.

BACKGROUND AND OBJECTIVES: The antimuscarinic drug trospium chloride is hydrophilic and therefore does not enter the CNS when used for the treatment of overactive bladder disturbances. However, the same property is the main reason for low and variable oral bioavailability. The present study was performed to assess the influence of intestinal site on absorption of the drug as the basis for the development of modified release preparations. METHODS: In a change-over pilot study, 8 healthy male volunteers received single 20 mg doses oftrospium chloride orally as a tablet (reference), as Eudragit-coated tablets dissolving at pH 6.0 (local administration into the small intestine), and rectally via a mini enema (corresponding to local administration into the large intestine). Plasma concentrations of trospium chloride were determined up to 36 hours after administration using GC/MS. RESULTS: Extent and rate of trospium chloride absorption declined rapidly upon administration into more distal regions of the gastrointestinal tract. C(max) (median: 6.42 ng/ml) and AUC(0.tlast) (42.28 ng/ml x h) were highest and t(max) (3.5 h) was shortest after administration of the reference tablet. AUC(0-tlast) reached 78% (90% CI 43 - 139%) after small intestine administration and 2% (90% CI 1 - 9%) following rectal administration, respectively, relative to the values for the oral tablet. CONCLUSION: Trospium chloride is absorbed primarily in the upper gastrointestinal tract. Development of modified release preparations must balance prolonged apparent absorption rates of the drug against a decrease in bioavailability.

Administration, Oral↗