Slow gastric emptying induced by high fat content of meal accelerated by cisapride administered rectally

The Impact of Diet and Exercise on Drug Responses

It is well known that lifestyle changes can alter several physiological functions in the human body. For exercise and diet, these effects are used sensibly in basic therapies, as in cardiovascular diseases. However, the physiological changes induced by exercise and a modified diet also have the capacity to influence the efficacy and toxicity of several drugs, mainly by affecting different pharmacokinetic mechanisms. This pharmacological plasticity is not clinically relevant in all cases but might play an important role in altering the effects of very common drugs, particularly drugs with a narrow therapeutic window. Therefore, with this review, we provide insights into possible food–drug and exercise–drug interactions to sharpen awareness of the potential occurrence of such effects.

Pharmacokinetics, Pharmacodynamics, and PKPD Modeling of Curcumin in Regulating Antioxidant and Epigenetic Gene Expression in Healthy Human Volunteers

Curcumin is a major component of the spice turmeric ( Curcuma longa), often used in food or as a dietary supplement. Many preclinical studies on curcumin suggest health benefits in many diseases due to its antioxidant/anti-inflammatory and epigenetic effects. The few human studies and curcumin's unfavorable pharmacokinetics (PK) have limited its potential, leading researchers to study and develop formulations to improve its PK. The purpose of this clinical study is to describe the acute pharmacokinetics and pharmacodynamics (PK/PD) of commercially marketed curcumin in normal, healthy human volunteers. Twelve volunteers received a 4 g dose of curcumin capsules with a standard breakfast. Plasma samples were collected at specified time points and analyzed for curcumin and its glucuronide levels. RNA was extracted from leukocytes and analyzed for expression of select antioxidant and epigenetic histone deacetylase (HDAC) genes. Plasma levels of parent curcumin were below the detection limit by HPLC-ITMS/MS/MS. However, curcumin-O-glucuronide (COG), a major metabolite of curcumin, was detected as soon as 30 min. These observations of little to no curcumin and some levels of metabolite are in line with previous studies. PD marker antioxidant genes NRF2, HO-1, and NQO1 and epigenetic genes HDAC1, HDAC2, HDAC3, and HDAC4 were quantified by qPCR. COG PK is well-described by a one-compartment model, and the PK/PD of COG and its effect on antioxidant and epigenetic gene expression are captured by an indirect response model (IDR). A structural population PK model was sequentially established using a nonlinear mixed-effect model program (Monolix Lixoft, Orsay, France). Physiologically based pharmacokinetic modeling (PBPK) and simulation using Simcyp correlated well with the observed data. Taken together, these results show that the bioavailability of the parent curcumin compound is low, and oral administration of curcumin can still deliver detectable levels of curcumin glucuronide metabolite. But most importantly, it elicits antioxidant and epigenetic effects which could contribute to the overall health beneficial effects of curcumin.

Acute exercise and gastric emptying: a meta-analysis and implications for appetite control

BACKGROUND

Gastric emptying (GE) could influence exercise-induced changes in appetite and energy intake. GE also could contribute to changes in gastric symptoms and the availability of nutrients during exercise, which will subsequently affect performance.

OBJECTIVE

The objective of this review was to determine the effects of acute exercise on GE using a systematic review and meta-analysis. The most common parameters to determine GE were selected, consisting of half-emptying time and volume emptied. Oral-caecal transit time (OCTT) was also examined.

DATA SOURCES

Research databases (PubMed, Scopus, Google Scholar, EBSCOhost, SPORTDiscus) were searched through November 2013 for original studies, abstracts, theses and dissertations that examined the influence of acute exercise on GE.

STUDY SELECTION

Studies were included if they evaluated GE or OCTT during and/or after exercise and involved a resting control trial.

STUDY APPRAISAL AND SYNTHESIS

Initially, 195 studies were identified. After evaluation of study characteristics and quality and validity, data from 20 studies (35 trials) involving 221 participants (157 men; 52 women; 12 unknown) were extracted for meta-analysis. Random-effects meta-analyses were utilised for the three main outcome variables, and effect sizes (ES) are reported as Hedge's g due to numerous small sample sizes.

RESULTS

Random-effects modelling revealed non-significant and small/null main effect sizes for volume emptied (ES = 0.195; 95% CI -0.25 to 0.64), half-time (ES = -0.109, 95% CI -0.66 to 0.44) and OCTT (ES = 0.089; 95% CI -0.64 to 0.82). All analyses exhibited significant heterogeneity and numerous variables moderated the results. There was a dose response of exercise intensity; at lower intensities GE was faster, and at high exercise intensities GE was slower. Walking was associated with faster GE and cycling with slower GE. Greater volume of meal/fluid ingested, higher osmolality of beverage and longer exercise duration were also associated with slower GE with exercise.

LIMITATIONS

The major limitation is that the majority of studies utilised a liquid bolus administered pre-exercise to determine GE; the relationship to post-exercise appetite and energy intake remains unknown. Study populations were also generally active or trained individuals. Furthermore, our review was limited to English language studies and studies that utilised resting control conditions.

CONCLUSIONS

These results suggest that exercise intensity, mode, duration and the nature of meal/fluid ingested all influence GE during and after acute exercise. The relationship of GE parameters with appetite regulation after exercise remains largely unexplored. Further integrative studies combining GE and alterations in gut hormones, as well as in populations such as overweight and obese individuals are needed.

Effects of food and alcohol on the pharmacokinetics of an oral, extended-release formulation of hydrocodone in healthy volunteers

BACKGROUND

The purpose of this study was to evaluate the pharmacokinetics, bioavailability, and safety of oral extended-release hydrocodone (HC-ER) when administered with food or alcohol.

METHODS

Two single-center, open-label, randomized, crossover studies were conducted in healthy volunteers. In a two-period food-interaction study, 12 subjects received HC-ER 20 mg after an overnight fast and a high-fat meal. In a three-period alcohol-interaction study, 30 naltrexone-blocked subjects received HC-ER 50 mg with a 0%, 20%, or 40% alcohol/orange juice solution after an overnight fast. Pharmacokinetic parameters were derived from plasma concentrations of hydrocodone and its metabolites.

RESULTS

Exposure to hydrocodone after HC-ER 20 mg was similar in the fed and fasted states, as assessed by area under the plasma concentration versus time curve from time of dosing to time of last detectable concentration (AUC0-t; 316.14 versus 311.94 ng · h/mL); relative bioavailability (Frel) was 101.74%. Differences (fed versus fasted) in hydrocodone mean maximum plasma concentration (Cmax; 28.86 versus 22.74 ng/mL) and median time to Cmax (tmax; 6 versus 8 hours) were not clinically significant. Administration of 20% alcohol with HC-ER 50 mg did not increase systemic exposure relative to 0% alcohol (AUC0-t 878 versus 832 ng · h/mL; Frel 105%) or result in clinically meaningful changes in Cmax (51.8 versus 46.3 ng/mL) or tmax (5.44 versus 6.16 hours). Administration with 40% alcohol increased AUC0-t (1,008 ng · h/mL versus 832 ng · h/mL; Frel 120%) and Cmax (109 versus 46.3 ng/mL), and shortened tmax (2.43 versus 6.16 hours). Adverse events occurred in 10.0%, 24.1%, and 66.7% of subjects after 0%, 20%, and 40% alcohol, respectively.

CONCLUSION

HC-ER can be administered without regard to meals. While there was no evidence of "dose-dumping" (an unintended, rapid release in a short time period of all or most of the hydrocodone from HC-ER), even with 40% alcohol, as with all opioids, alcohol should not be ingested while using HC-ER.

Systematic review: cardiovascular safety profile of 5-HT(4) agonists developed for gastrointestinal disorders

BACKGROUND

The nonselective 5-HT(4) receptor agonists, cisapride and tegaserod have been associated with cardiovascular adverse events (AEs).

AIM

To perform a systematic review of the safety profile, particularly cardiovascular, of 5-HT(4) agonists developed for gastrointestinal disorders, and a nonsystematic summary of their pharmacology and clinical efficacy.

METHODS

Articles reporting data on cisapride, clebopride, prucalopride, mosapride, renzapride, tegaserod, TD-5108 (velusetrag) and ATI-7505 (naronapride) were identified through a systematic search of the Cochrane Library, Medline, Embase and Toxfile. Abstracts from UEGW 2006-2008 and DDW 2008-2010 were searched for these drug names, and pharmaceutical companies approached to provide unpublished data.

RESULTS

Retrieved articles on pharmacokinetics, human pharmacodynamics and clinical data with these 5-HT(4) agonists, are reviewed and summarised nonsystematically. Articles relating to cardiac safety and tolerability of these agents, including any relevant case reports, are reported systematically. Two nonselective 5-HT(4) agonists had reports of cardiovascular AEs: cisapride (QT prolongation) and tegaserod (ischaemia). Interactions with, respectively, the hERG cardiac potassium channel and 5-HT(1) receptor subtypes have been suggested to account for these effects. No cardiovascular safety concerns were reported for the newer, selective 5-HT(4) agonists prucalopride, velusetrag, naronapride, or for nonselective 5-HT(4) agonists with no hERG or 5-HT(1) affinity (renzapride, clebopride, mosapride).

CONCLUSIONS

5-HT(4) agonists for GI disorders differ in chemical structure and selectivity for 5-HT(4) receptors. Selectivity for 5-HT(4) over non-5-HT(4) receptors may influence the agent's safety and overall risk-benefit profile. Based on available evidence, highly selective 5-HT(4) agonists may offer improved safety to treat patients with impaired GI motility.

Effect of a high-fat meal on the pharmacokinetics of dapagliflozin, a selective SGLT2 inhibitor, in healthy subjects

Dapagliflozin is a potent and selective inhibitor of sodium-glucose co-transporter type 2 that is being developed for the treatment of type 2 diabetes mellitus. This open-label, randomized, two-period, two-treatment (single doses of 10-mg dapagliflozin fasted or fed), crossover study was conducted to evaluate the effect of a high-fat meal on the pharmacokinetics of dapagliflozin in 14 healthy subjects. Compared to the fasted state, a high-fat meal decreased mean dapagliflozin maximum plasma concentrations (C(max) ) by 31%, increased the time to C(max) (T(max) ) by 1 h, but did not affect overall dapagliflozin systemic exposure [area under the plasma concentration-time curve (AUC)]. As the cumulative (daily) amount of glucose excreted in the urine induced by dapagliflozin is dependent upon dapagliflozin AUC, the effect of food on dapagliflozin C(max) is unlikely to have a clinically meaningful effect on dapagliflozin's efficacy. On the basis of these findings, dapagliflozin can be administered without regard to meals.

Cisapride: what can we learn from the rise and fall of a prokinetic?

Cisapride, the prototype serotonergic agent, evolved from a body of research that defined the key roles of serotonergic receptors in gastrointestinal motor and sensory function. Impressed by its in vitro properties and encouraged by clinical trial data, cisapride became the drug of choice for the treatment of a wide range of motility disorders and clinicians appeared impressed by its efficacy and comfortable with its side-effect profile. Once serious cardiac events began to be reported in association with cisapride therapy, dark clouds rapidly gathered and soon enveloped the drug, leading to its widespread withdrawal from markets. What lessons can we learn from the story of cisapride? How can its brief but spectacular rise and equally sensational demise inform the development of new drugs which are so sorely needed in the management of motility and functional gastrointestinal disorders? This review explores the background to the development of cisapride, its history in clinical trials and the experience with adverse events and, in so doing, attempts to identify lessons for the future in the therapeutics of enteric neuromodulatory drugs.

Effects of lipase inhibition on gastric emptying and alcohol absorption in healthy subjects

The rate of alcohol absorption is dependent on gastric emptying (GE). As the slowing of GE by fat is dependent on lipolysis, orlistat may increase the rise in blood alcohol when alcohol is consumed with, or after, fat. The aim of the study was to evaluate the effects of orlistat on GE and blood alcohol after an alcohol-containing drink following a fat 'preload', in healthy subjects. Ten healthy males consumed 120 ml cream with or without 120 mg orlistat, 30 min before an alcohol-containing drink labelled with 20 MBq [(99 m)Tc]sulfur colloid on 2 d. GE, plasma alcohol and blood glucose were measured. GE was slightly faster with orlistat (P<0.05) compared with control. Plasma alcohol at 15 min was slightly higher with orlistat (0.034 (SEM 0.006) g/100 ml) v. control (0.029 (SEM 0.005) g/100 ml) (P<0.05), but there was no effect on the area under the curve 0-240 min. The increase in blood glucose was greater with orlistat, for example, at 15 min (1.07 (SEM 0.2) mmol/l) v. control (0.75 (SEM 0.2) mmol/l) (P=0.05). The rise in blood glucose and plasma alcohol were related (for example, at 15 min r 0.49; P=0.03). In conclusion, lipase inhibition accelerates GE of an alcohol-containing drink following a fat 'preload' with a minor increase in the initial rise in plasma alcohol.

Delayed gastric emptying in the obese: an assessment using the non-invasive (13)C-octanoic acid breath test

AIM

Much of the controversy surrounding the correlation between obesity and gastric emptying lies in the inconsistency of methodology and analysis. This study was designed to overcome some of the discrepancies encountered in previous studies and to test the hypothesis that obese individuals have altered gastric emptying compared to lean individuals.

METHODS

Gastric emptying was measured using the (13)C-octanoic acid breath test in 16 lean and 16 obese women pair-matched for age. Following an overnight fast, subjects were given a standard 2 MJ egg meal labelled with 100 microl of [1-(13)C]-octanoic acid. Breath samples were collected at regular intervals over a 6-h period. (13)C-isotopic enrichment in the breath was analysed using isotope ratio mass spectrometry and the data fitted to the established gastric emptying model. The lag times (t(lag)), half excretion times (t(1/2)), latency phase (t(lat)) and ascension times (t(asc)) were calculated.

RESULTS

The mean t(1/2)-values (+/-standard error of the mean) were 3.67 +/- 0.14 h and 4.23 +/- 0.18 h for lean and obese respectively, indicating significantly delayed gastric emptying in the obese (p = 0.019). The obese group also showed a significantly slower lag time (t(lag), p = 0.005) and latency phase (t(lat), p = 0.005), but no significant difference was found in the ascension time (t(asc), p = 0.154). Within groups, no correlation was found between half excretion times and body weight or half excretion times and body mass index.

CONCLUSIONS

The present study demonstrated a prolonged lag phase and delayed gastric emptying in obese women when compared to lean women. This delay may be as a consequence of high-fat diets, a sedentary lifestyle and increased gastric distension associated with obesity, or a contributing factor in the pathogenesis of obesity resulting from the inactivation of gastrointestinal satiety signals and in an increase in food intake.

Is rectally administered cisapride an effective prokinetic agent?

OBJECTIVE

To summarize the published data on the efficacy of rectally administered cisapride.

DATA SOURCES

Published double-blind, placebo-controlled trials on rectally administered cisapride identified by MEDLINE (January 1966-December 1998) and International Pharmaceutical Abstracts (January 1970-December 1998) searches.

DATA SYNTHESIS

Cisapride is an oral prokinetic agent that increases lower esophageal sphincter tone, accelerates gastric emptying, and increases small-bowel motility. Clinical trials of rectal cisapride have used both single- and multiple-dosing regimens. Typically, patients received one or two 30-mg suppositories (provided by the manufacturer). Rectal cisapride was effective in enhancing gastric emptying of solid or semisolid meals in healthy patients or patients with chronic gastric emptying disorders. Rectal cisapride was not effective in antagonizing the gastrointestinal effects of narcotic analgesics or promoting the return of small-bowel activity in adults with postoperative ileus. Mixed results were seen when rectal cisapride was used to promote enteral feedings in patients with persistent ileus.

CONCLUSIONS

The use of rectal cisapride cannot be recommended at this time. Rectal cisapride was effective only in patients who could have otherwise taken either cisapride tablets or suspension but it was not effective in patients who are physically unable to swallow or restricted from ingesting anything orally following surgical procedures. Considering the varied patient populations and evaluation methods used in these studies, the lack of a commercially available cisapride suppository, and absence of studies involving extemporaneously prepared cisapride suppositories, the use of suppositories should be limited to investigational trials.

Functional gut disorders: from motility to sensitivity disorders. A review of current and investigational drugs for their management

Functional gut disorders include several clinical entities defined on the basis of symptom patterns (e.g., functional dyspepsia, irritable bowel syndrome, functional abdominal pain, functional abdominal bloating), for which there is no established pathophysiological mechanism. Because there is no well-defined pathophysiological target, treatment should be aimed at symptom improvement. Prokinetics and antispasmodics have been widely used in the treatment of functional gut disorders on the assumption that disordered motility is the underlying cause of symptoms, and symptom improvement is indeed achievable with these compounds in some, but not all, patients with features of hypo- or hypermotility, respectively. In the first part of this review, we cover the basic pharmacology and discuss the rationale for the clinical use of prokinetics and antispasmodics. On the other hand, in the past few years, the explosive growth in the research focusing on visceral sensitivity and visceral reflexes has suggested that at least some patients with functional gut disorders have altered visceral perception. Thus, the second part of the review covers these developments and focuses on studies addressing the issue of drugs modulating visceral sensitivity.

Role of sham feeding in postprandial changes of gastric myoelectrical activity

The aim of this study was to evaluate the role of sham feeding in postprandial changes of gastric myoelectrical activity. Eighteen asymptomatic healthy volunteers (10 men, 8 women; mean age: 31), with no history of gastrointestinal disease were studied. Gastric myoelectrical activity was recorded for 30 min at baseline, 30 min after sham feeding, and 1 hr after eating, using surface electrogastrography. The electrogastrogram (EGG) was analyzed by spectral analysis. It was found that the changes of postprandial EGG parameters were significantly correlated with those after sham feeding (EGG dominant power: r = 0.6, P < 0.01; dominant frequency: r = 0.8, P < 0.001; percentage of regular slow waves: r = 0.7, P < 0.003). We concluded that intrinsic gastric electrical activity can be altered by sham feeding and the cephalic phase of digestion plays an important role in the postprandial response of gastric myoelectrical activity.

Effects of cisapride on gastric emptying of oil and aqueous meal components, hunger, and fullness

To evaluate the effects of cisapride on gastric emptying of extracellular fat and hunger and fullness 10 volunteers consumed a meal consisting of 60 ml technectium-99m (99mTc)-V-thiocyanate labelled olive oil and 290 ml indium-113m (113mIn) labelled soup after taking cisapride (10 mg four times daily orally) and placebo, each for four days, in randomised, double blind fashion. Gastric emptying was quantified scintigraphically. Hunger and fullness before and after the meal were evaluated using visual analogue scales. Cisapride accelerated gastric emptying of oil and aqueous components by reducing the lag phase mean (SEM) (20.3 (7.0) min v 40.7 (4.1) min (p < 0.05) for oil and 4.1 (2.5) min v 10.0 (3.1) min (p < 0.05) for aqueous). Cisapride had no effect on the post-lag emptying rate of oil. Treatment with cisapride was associated with reduced retention of oil in the proximal stomach (p < 0.05). Subjects were more hungry before ingestion of the meal while receiving cisapride (6.7 (0.9) v 3.9 (0.7), p < 0.001). The scores for hunger at 120 and 180 minutes were inversely related to gastric emptying of oil on both cisapride (r > -0.62, p < 0.05) and placebo (r > -0.86, p < 0.001). Fullness increased after the meal while receiving placebo (p < 0.01), but not cisapride and postprandial fullness was less with cisapride at (30 min; 0.4 (0.3) v 3.3 (1.0), p < 0.05). With placebo, but not cisapride, the score for fullness at 15 minutes was inversely related to emptying of the aqueous phase (r = 0.68, p < 0.05). These results show that in normal volunteers after ingestion of an oil/aqueous meal: (a) postprandial hunger is inversely related to gastric emptying of oil, while fullness is inversely related to gastric emptying of the aqueous phase, (b) cisapride affects the intragastric distribution and accelerates gastric emptying of both oil and aqueous meal components, and (c) cisapride increases preprandial hunger and reduces postprandial fullness.

The effect of intravenous lipids on gastric emptying in rats subjected to total parenteral nutrition

Total parenteral nutrition (TPN) is indicated in a number of clinical situations involving obstructive disorders of the gastrointestinal tract or when total bowel rest is required. However, little is known of its effects upon the physiology of gastric storage and emptying. A study of the effects of lipid nutrient content of TPN on the gastric emptying of a non-energy liquid test meal in male and female conscious rats (250-280 g) was undertaken. Five experimental groups were set up according to the percentage of total non-protein energy administered in the form of different lipids: A (lipid-free: 100% of non-protein energy as glucose); B (5% long-chain triglycerides (LCT), 95% glucose); C (40% LCT, 60% glucose); D (5% LCT and medium-chain triglycerides (MCT) in 1:1 proportion, 95% glucose); and E (40% LCT and medium-chain triglycerides (MCT) in 1:1 proportion, 60% glucose). Animals were maintained on TPN for 24 h and for 3 and 4 days, after which gastric emptying was measured by the phenol red method. 40% lipid TPN was found to accelerate gastric emptying as infusion was prolonged, although the type of lipid had no effect.

Cisapride. An updated review of its pharmacology and therapeutic efficacy as a prokinetic agent in gastrointestinal motility disorders

Cisapride is an orally administered prokinetic agent which facilitates or restores motility throughout the length of the gastrointestinal tract. It is a substituted piperidinyl benzamide, chemically related to metoclopramide, but unlike metoclopramide, cisapride is largely devoid of central depressant or antidopaminergic effects. In placebo-controlled trials, cisapride improved healing rates and symptoms in both adults and children with reflux oesophagitis. Maintenance therapy with cisapride at half the healing dose is effective in reducing the incidence of relapse. Symptoms are also alleviated in patients with functional dyspepsia, and gastric emptying and symptoms are improved in most patients with gastroparesis, an effect which is sustained during long term administration. However, the efficacy of cisapride in end-stage gastroparesis remains less clear. Cisapride increases stool frequency in patients with chronic constipation, and limited data suggest that the drug may also be beneficial in treating chronic intestinal pseudo-obstruction and irritable bowel syndrome. Cisapride demonstrated efficacy comparable with or superior to that of metoclopramide, and was at least as effective as cimetidine and ranitidine in patients with reflux disease. In patients with functional dyspepsia, cisapride has shown at least equal efficacy to domperidone, metoclopramide and ranitidine, and superior efficacy to cimetidine in the small comparative trials conducted to date. Adverse effects in patients receiving cisapride are generally transient and mild, with abdominal cramping, borborygmi, diarrhoea or loose stools most frequently reported. Central nervous system adverse effects are rare. Thus, with its favourable tolerability profile and demonstrated efficacy in a variety of gastrointestinal motility disorders, the position of cisapride as a valuable agent in the management of patients with gastrointestinal motility disorders is strengthening. However, larger well-controlled comparative trials of the drug with other agents are necessary before the relative position of cisapride in therapy can be categorically defined.