The influence of food on the absorption and metabolism of drugs

The effect of food on the pharmacokinetics of Sutetinib maleate capsule, an irreversible EGFR tyrosine kinase inhibitor, in healthy Chinese subjects

Sutetinib is an irreversible inhibitor of epidermal growth factor receptor (EGFR) and showed favorable efficacy and safety in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harbouring nondrug-resistant rare EGFR mutations. To evaluate the potential food effect, eighteen healthy Chinese subjects were enrolled in a single-centre, randomized, open-label, two-sequence, two-period crossover study. Sutetinib was administered as a single oral 100 mg under fasting or fed conditions, and pharmacokinetic sampling was performed following each dose and analysed by a validated liquid chromatography/mass spectrometry method. Safety and tolerability were also evaluated. Food intake slightly decreased maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time 0 to infinity (AUC0 - inf) of sutetinib (geometric least-squares mean [GLSM] ratio, 80.94% and 86.11%; 90% confidence interval [CI], 68.43-95.72 and 75.88-97.73) and its active metabolite sutetinib N-Oxide (GLSM ratio, 75.58% and 84.00%; 90% CI, 65.69-86.95 and 75.42-93.56), respectively. In addition, the time to maximum plasma concentration (Tmax) of both sutetinib and its metabolite has been prolonged by 2 h under fed conditions. A total of 31 adverse events (AEs) occurred during the study, with no serious adverse events (SAE) reported, and no obvious difference was observed between the fasting and fed groups. Our results demonstrated that a high-fat and high-calorie diet caused a significant delay in drug absorption and a marginal reduction in drug exposure. Sutetinib was generally well tolerated in healthy Chinese subjects. (This trial was registered at http://www.chinadrugtrials.org.cn . The registration No. is CTR20201933, and the date of registration is 2020-10-16).

Potential Role of Lipase Activity on the Internal Exposure Assessment of Glycidol Released from Its Fatty Acid Esters

Glycidyl fatty acid esters (GEs) can be found in food, and they can be converted into genotoxic animal carcinogen glycidol in vivo by the action of lipase. This study examined whether human ingestion of charbroiled pork containing high levels of GEs (300 µg/day) increased glycidol-hemoglobin adduct (diHOPrVal), a marker of internal exposure to glycidol using LC-MS/MS. Contrary to expectation, the diHOPrVal value before ingesting charbroiled pork was 3.11 ± 1.10 pmol/g globin, which slightly decreased to 2.48 ± 0.47 pmol/g globin after 5 days of consumption. The decrease in lipase activity caused by the continuous consumption of lipid-rich foods such as meat in humans might decrease internal exposure to glycidol released from its esters. Thus, lipase activity was measured in C57/BL6J mice fed a high-fat diet (HFD) for 8 weeks, and diHOPrVal formation was measured after the administration of glycidyl oleate. Lipase activity was significantly lower in the HFD group than in the normal diet group. The amount of diHOPrVal was reduced in the HFD group. Therefore, the lipase activity was reduced by HFD, thereby decreasing the degradation of glycidol from glycidyl oleate. These results indicate that changes in lipase activity depending on the amount of lipids in the diet may affect the assessment of GEs exposure, and monitoring the lipase activity would provide a comprehensive understanding of exposure assessment.

Development and Validation of HPLC-DAD Method for the Determination of Favipiravir and Studying the Impact of Vitamin C on the Pharmacokinetics of COVID-19 Antiviral Drug Favipiravir

A novel, sensitive, and low-cost HPLC method for the rapid determination of favipiravir (FVR) in rat plasma was developed and validated, and the effect of vitamin C on FVR pharmacokinetic parameters was investigated. FVR and oxcarbazepine (IS) were separated using a mobile phase of 50% acetonitrile and 50% water (with 0.25% trifluoroacetic acid) at 1.0 mL/min flow rate and detected at λmax 289 nm. The intra- and interday values for FVR in plasma were less than 15%, with low, medium, and high QC levels for the relative recovery rate, according to ICH guidelines. Cmax values in the control and experimental groups were 558 ± 124.42 and 979.13 ± 138.10 ng/mL, respectively; t1/2 values were 7.15 ± 1.60 and 9.09 ± 1.14 h, AUC(0-t) values were 5697.70 ± 536.58 and 7381.62 ± 1577.58 ng.h/mL, and AUC(0-∞) values were 5697.70 ± 536.58 and 8192.36 ±  1721.67, respectively. According to the results, the experimental group’s Cmax of FVR was 75.17% higher than the control group’s, the Vz/F was lower, and the t1/2 was 1.86 h longer. The technique developed for determining FVR in plasma was useful for FVR pharmacokinetics and food–drug interaction investigations.

The Effect of Grapefruit Juice on the Pharmacokinetics of Tadalafil in Rats

We developed and validated a novel, sensitive, selective, and inexpensive high-performance liquid chromatography (HPLC) method for the determination of tadalafil in rats plasma and to investigate the effect of grapefruit juice on the pharmacokinetics of tadalafil in rats. The ZORBAX Eclipse XDB-C18 (4.6 × 150 mm, 5 μm) chromatography column can be used to separate tadalafil and carbamazepine (internal standard, IS). A mixture of acetonitrile-0.2% trifluoroacetic acid-water (48 : 10 : 42, V/V/V) was used as the mobile phase with a flow rate of 1.0 mL/min. The column temperature was set at 35.0°C. The detection wavelength was set at 286 nm. The tadalafil was extracted by ethyl acetate from plasma at the alkaline condition. 12 healthy male Sprague-Dawley (SD) rats were randomly divided into two groups, Group A (experimental group, received grapefruit juice 5 mL/kg for 7 days) and Group B (control group, received normal saline for 7 days). All the rats were given a single dose of tadalafil (5 mg/kg) after the last administration. The main pharmacokinetic parameters were calculated by DAS 2.0 software. Under the conditions of this experiment, the plasma concentrations of tadalafil in the range of 10–2000 ng/ml had a good linear relationship. The intra- and interday precision for tadalafil in plasma were less than 15%, and the relative recovery rate was good at low, medium, and high QC levels. The C_max of tadalafil in the control group and the experimental group was (725.89 ± 161.59) ng/mL and (1271.60 ± 179.31) ng/mL, t_1/2 was (9.28 ± 2.07) h and (11.70 ± 1.47) h, AUC _(0-t) was (7399.61 ± 696.85) ng·h/mL and (9586.52 ± 2048.81) ng·h/mL, and AUC_(0-∞) was (7995.50 ± 707.23) ng·h/mL and (10639.43 ± 2235.94) ng·h/mL, respectively. Results show that the C_max of tadalafil in group A was 75.17% higher than that in group B, the Vz/F was also reduced, and the t_1/2 was increased by 2.42 h. The developed HPLC–DAD method for the determination of tadalafil in rats plasma was accurate, reproducible, specific, and it was found to be suitable for the pharmacokinetics of tadalafil and food-drug interactions. Grapefruit juice can inhibit the metabolism of tadalafil and increase the exposure of tadalafil in rats.

An Investigation into the Factors Governing Drug Absorption and Food Effect Prediction Based on Data Mining Methodology

Drug absorption is a complex process governed by a number of interrelated physicochemical, biopharmaceutical, and pharmacokinetic factors. In order to explore complex relationships among these factors, multivariate exploratory analysis was performed on the dataset of drugs with diverse bioperformance. The investigated dataset included subset of drugs for which bioequivalence between solid dosage form and oral solution has been reported, and subset of drugs described in the literature as low solubility/low permeability compounds. Discriminatory power of hierarchical clustering on principal components was somewhat higher when applied on the data subsets of drugs with similar bioperformance, while analysis of the integrated dataset indicated existence of two groups of drugs with the boundaries reflected in P_eff value of approximately 2 × 10^-4 cm/s and Fa and Fm values higher than 85% and 50%, respectively. Majority of the investigated drugs within the integrated dataset were grouped within their initial subset indicating that overall drug bioperformance is closely related to its physicochemical, biopharmaceutical and pharmacokinetic properties. Classification models constructed using the random forest (RF) and support vector machine with polynomial kernel function were able to predict food effect based on drug dose/solubility ratio (D/S), effective permeability (P_eff), percent of dose metabolized (Fm), and elimination half-life (τ_1/2). Although both models performed well during training and testing, only RF kept satisfying performance when applied on the external dataset (kappa value > 0.4). The results obtained indicate that data mining can be employed as useful tool in biopharmaceutical drug characterization which merits further investigation.

Food Does Not Affect the Pharmacokinetics of Tesaglitazar, a Novel Dual Peroxisome Proliferator-Activated Receptor α/γ Agonist

Tesaglitazar is a dual peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist in development to treat lipid and glucose abnormalities associated with type 2 diabetes. This study evaluated the effects of food on tesaglitazar pharmacokinetics. In an open, randomized, 2-way crossover study, 20 healthy men received tesaglitazar 1 mg during fasting and after a high-fat, high-calorie breakfast. Blood samples were taken to assess pharmacokinetic variables. Systemic exposure to tesaglitazar was unaffected by food intake. Estimated ratios were 0.99 (90% confidence interval [CI], 0.94-1.04) for fed/fasted area under plasma concentration-time curve and 0.82 (90% CI, 0.78-0.86) for fed/fasted maximum plasma concentration (C(max)). Mean C(max) was approximately 18% lower (0.41 [95% CI, 0.38-0.43] versus 0.50 [95% CI, 0.47-0.53] mumol/L), and median time to C(max) was increased (2.00 vs 0.75 h) in fed versus fasted state. The median difference of t(max) was 1.25 h (P = .0001, signed-rank test). Tesaglitazar was well tolerated. Tesaglitazar pharmacokinetics is unaffected by food intake, allowing once-daily administration of tesaglitazar with or without food in clinical practice.

Effect of food on systemic exposure to niflumic acid following postprandial administration of talniflumate

PURPOSE

Talniflumate was designed as a prodrug of niflumic acid, a potent analgesic and anti-inflammatory drug, which is widely prescribed for treating rheumatoid diseases. The prandial effect on talniflumate absorption remains unclear; therefore, this study investigated the effect of food on the systemic exposure to niflumic acid in healthy volunteers.

METHODS

Volunteers received a single 740-mg dose of talniflumate 30 min after consuming a high-fat breakfast, a low-fat breakfast, or no food (fasting condition). Plasma concentrations of both talniflumate and niflumic acid were measured using validated high-performance liquid chromatography coupled to tandem mass spectrometry.

RESULTS

The maximum concentration of niflumic acid was 224 +/- 193 ng/ml at approximately 2.7 h in the fasted condition compared with 886 +/- 417 ng/ml (p < 0.05) at 1.8 h and 1,159 +/- 508 ng/ml (p < 0.01) at 2.2 h with the low- and high-fat meals, respectively. The mean area under the curve from zero to infinity (AUC(inf)) values after the low- and high-fat meals were four- and fivefold, respectively, the value while fasting (p < 0.05).

CONCLUSIONS

It is strongly recommended that talniflumate be taken after a meal to increase systemic exposure to its active metabolite. Our results suggest a reduction in the daily dosage of talniflumate when taken with food.

Food-drug interactions in the summary of product characteristics of proprietary medicinal products

BACKGROUND

Food-drug interactions can produce negative effects in the safety and efficacy of drug therapy, as well as in the nutritional status of the patient. However, the data commonly provided to the prescriber about possible nutrient-pharmacological compound interactions and the recommendations for their prevention are often scarce. The summary of product characteristics (SmPC) of a proprietary medicinal product, as authorised by the health authorities in Europe, is usually the main source of information for the health professional. Therefore, the SmPC can be a useful tool to prevent or reduce food-drug interactions and, as a consequence, improve the therapeutical approach.

OBJECTIVE

The aim of this study was to assess the information about food-drug interactions with potential clinical relevance as it is described in the SmPCs of the authorised medicinal products in a European Union country (Spain).

METHODS

A bibliographical search of food-drug interactions, including nutrients and alcohol, was carried out. The adequate information to be included in the SmPC was defined in accordance with the European Recommendations in this field. The SmPCs of the medicinal products containing selected active substances were examined with emphasis on food-drug interactions.

RESULTS

It was found that, frequently, the information concerning food-drug interactions as is mentioned in the SmPC of the authorised medicinal products in Spain does not fulfil the current recommendations, both in quantity and quality. Indeed, the available data reveal that the food-drug information is only mentioned in 72.7% of all SmPC where it should be and it was only found in the specific section for interactions in 36.0% of all cases. The description and agreement with recommendations for each SmPC item ranged between 4.2% and 36.0% and between 31.8% and 49.0%, respectively. Some related factors, such as the clinical relevance of the interaction, the existence of an authorised SmPC and the registration procedure followed, influence the information characteristics concerning food-drug interactions.

CONCLUSION

The SmPC is a suboptimal source of information for food-drug interactions.

Bicalutamide

Bicalutamide is a nonsteroidal pure antiandrogen given at a dosage of 150 mg once daily as monotherapy for the treatment of early (localised or locally advanced) nonmetastatic prostate cancer. It is used at a dosage of 50 mg once daily in combination with a luteinising hormone-releasing hormone analogue or surgical castration for the treatment of advanced prostate cancer. Bicalutamide is a racemate and its antiandrogenic activity resides almost exclusively in the (R)-enantiomer, with little, if any, activity in the (S)-enantiomer. (R)-Bicalutamide is slowly and saturably absorbed, but absorption is unaffected by food. It has a long plasma elimination half-life (1 week) and accumulates about 10-fold in plasma during daily administration. (S)-Bicalutamide is much more rapidly absorbed and cleared from plasma; steady-state concentrations (Css) of (R)-bicalutamide are 100-fold higher than those of (S)-bicalutamide. Css increases linearly with doses up to 50 mg, but nonlinearly at higher doses, reaching a plateau above 300 mg. Css is higher in Japanese than in Caucasians, but no relationship with degree of renal impairment, bodyweight or age exists. Although mild-to-moderate hepatic impairment does not affect pharmacokinetics, there is evidence for slower elimination of (R)-bicalutamide in subjects with severe hepatic impairment. Bicalutamide metabolites are excreted almost equally in urine and faeces with little or no unchanged drug excreted in urine; conversely, unchanged drug predominates in plasma. Bicalutamide in faeces is thought to arise from hydrolysis of bicalutamide glucuronide and from unabsorbed drug. Bicalutamide appears to be cleared almost exclusively by metabolism; this is largely mediated by cytochrome P450 (CYP) for (R)-bicalutamide, but glucuronidation is the predominant metabolic route for (S)-bicalutamide. (S)-Bicalutamide is metabolised in vitro by CYP3A4, and it is probable that this isoenzyme is also responsible for the metabolism of (R)-bicalutamide. In vitro data suggest that (R)-bicalutamide has the potential to inhibit CYP3A4 and, to a lesser extent, CYP2C9, 2C19 and 2D6. However, using midazolam as a specific CYP3A4 marker, no clinically relevant inhibition is observed in vivo with bicalutamide 150mg. Although bicalutamide is a CYP inducer in laboratory animals, dosages < or = 150 mg/day have shown no evidence of enzyme induction in humans. Daily administration of bicalutamide increases circulating levels of gonadotrophins and sex hormones; although testosterone increases by up to 80%, concentrations in most patients remain within the normal range. Bicalutamide produces a dose-related decrease in prostate-specific antigen (PSA) at dosages < or = 150 mg/day. However, little relationship is observed between median PSA reduction and (R)-bicalutamide Css.

Time effects of food intake on the pharmacokinetics and pharmacodynamics of quazepam

AIMS

There is little information on interaction between food and the hypnotic agent quazepam. We therefore studied the effects of food and its time interval on the pharmacokinetics and pharmacodynamics of quazepam.

METHODS

A randomized three-phase crossover study with 2-week intervals was conducted. Nine healthy male volunteers took a single oral 20 mg dose of quazepam under the following conditions: 1) after fasting overnight; 2) 30 min after eating standard meal; or 3) 3 h after eating the same meal. Plasma concentrations of quazepam and its metabolite, 2-oxoquazepam and psychomotor function using the Digit Symbol Substitute Test (DSST), Stanford Sleepiness Scale (SSS) and Visual Analogue Scale were measured up to 48 h.

RESULTS

During the food treatments at 30 min and 3 h before dosing, the peak concentrations (Cmax) were 300% (95% CI 260, 340%; P < 0.001) and 250% (95% CI 210, 290%; P < 0.01) of the corresponding value during the fasting phase. For quazepam, the area under the plasma concentration-time curve from 0 to 8 h measured at 30 min and 3 h before dosing was significantly increased, with the food treatments by 2.4-fold (95% CI 2.0; 2.8-fold; P < 0.001) and 2.1-fold (95% CI 1.7; 2.4-fold; P < 0.01), respectively. In response to pharmacokinetic changes, some of the pharmacodynamics (DSST, P < 0.05; SSS, P < 0.05) differed significantly between fasted status and fed status. No difference was found in any pharmacokinetic or pharmacodynamic parameters between the two food treatment phases.

CONCLUSIONS

A food effect on quazepam absorption is evident and continues at least until 3 h after food intake. The dosing of quazepam after a long period of ordinary fasting might reduce its efficacy because a 3 h interval between the timing of the evening meal and bedtime administration of hypnotics is regarded as normal in daily life.

Should we be concerned about herbal remedies

During the latter part of this century the practice of herbalism has become mainstream throughout the world. This is due in part to the recognition of the value of traditional medical systems, particularly of Asian origin, and the identification of medicinal plants from indigenous pharmacopeias that have been shown to have significant healing power, either in their natural state or as the source of new pharmaceuticals. Generally these formulations are considered moderate in efficacy and thus less toxic than most pharmaceutical agents. In the Western world, in particular, the developing concept that 'natural' is better than 'chemical' or 'synthetic' has led to the evolution of Neo-Western herbalism that is the basis of an ever expanding industry. In the US, often guised as food, or food supplements, known as nutriceuticals, these formulations are readily available for those that wish to self-medicate. Within this system, in particular, are plants that lack ethnomedical verification of efficacy or safety. Unfortunately there is no universal regulatory system in place that insures that any of these plant remedies are what they say they are, do what is claimed, or most importantly are safe. Data will be presented in this context, outlining how adulteration, inappropriate formulation, or lack of understanding of plant and drug interactions have led to adverse reactions that are sometimes life-threatening or lethal.

In vitro conditions for the study of the in vivo performance of sustained-release theophylline matrix tablets administered in fasted conditions and with a high-fat diet

Dissolution profiles of theophylline (TP) from three types of sustained-release (SR) matrix tablets (plastic [PL], lipid [LP], and hydrophilic [HP]) in different dissolution media, with and without enzymes, were established. Also investigated was the influence of a treatment of the tablets with peanut oil prior to the dissolution test. The in vivo behavior of the tablets under the fasted state and with the concomitant administration with a high-fat diet was previously evaluated; the diet produced changes in the absorption profiles for the three matrix tablets in comparison with fasted administration. Level A correlations were obtained between cumulative percentage dissolved (CPD) and cumulative percentage absorbed (CPA). For the fasted condition, better correlations were obtained with water as the dissolution medium for the HP and LP matrix; for PL matrix, the best correlation was obtained with a medium with gradual change of pH. The pretreatment with peanut oil showed better correlations for the fed state.

Factors influencing the bioavailability of peroral formulations of drugs for dogs

The oral route is presently the preferred route of drug delivery. Poor oral bioavailability results in variable concentrations of drugs in the plasma and variable pharmacological responses, in addition to higher product costs. The unique canine physiology, anatomy and biochemistry makes designing canine dosage forms a challenging exercise. This article reviews the physicochemical, physiological, pharmacokinetic, pharmacological and formulation factors that can influence the drug availability of the oral formulations in dogs in an effort to provide a source of data to aid development of canine drug products with superior bioavailability.

Evaluation of the in vitro and in vivo performance of two sustained-release lithium carbonate matrix tablets. Effect of different diets on the bioavailability

Two sustained-release (SR) lithium carbonate (Li) matrix tablets, which use a hydrophilic (HP) matrix of hydroxypropylmethylcellulose (Methocel 4K MP) and a lipid (L) matrix of hydrogenated castor oil (Cutina HR) as sustaining agents, have been studied. In vitro performance through dissolution tests in different media was established. The L and HP formulations were affected by the composition of the dissolution media, and liberation was complete in 8 hr using a variable-pH medium that simulates the gastrointestinal (Gl) pH. Liberation was better described by the diffusional model of the square root of time for the L matrix and by zero-order kinetics for the HP matrix. Absolute bioavailability (BA) and food-induced changes on BA of both formulations were studied. The in vivo study design was a 4 x 4 Latin square involving 12 subjects who received two tablets of a 300-mg dose of SR formulations while fasting or with a standardized normal, high-fat, or high-fat/high-protein meal. The results for both formulations showed no differences in the disposition parameters and mean residence time when the tablets were administered with any type of diet. Changes in rate of absorption were found when both types of tablets were administered with any class of diet. The analysis of the ratio Cmax/AUC (area under the curve) evidenced that changes in Cmax were attributable to a higher rate of absorption for the HP matrix and to a higher amount absorbed for the L matrix. In the last, high-fat and high-fat/high-protein diets produced higher AUCs than under fasting condition. The SR Li tablets formulated with hydrogenated castor oil were affected more by high-fat food, probably because of the increase of pancreatic and biliary secretions promoted by the meal, which would affect the matrix itself. The HP matrix was also affected, but to a lesser extent. The magnitude of the change in Cmax observed with this matrix probably is not important from a clinical point of view. Absolute BA was very low for the lipid matrix; in addition, since it is more seriously affected by food, probably it is not a good choice for a drug such as lithium. The in vivo behavior of the HP matrix makes it advisable to invest in efforts to achieve increased BA. Comparing in vitro and in vivo results, the focus should be achieving sustained, but complete, in vitro liberation in not more than 3 hr, with simulation of the transit time through the stomach and small bowel since lithium ion is only absorbed to this point.

Toxicokinetics of organic solvents: a review of modifying factors

This article reviews, with an emphasis on human experimental data, factors known or suspected to cause changes in the toxicokinetics of organic solvents. Such changes in the toxicokinetic pattern alters the relation between external exposure and target dose and thus may explain some of the observed individual variability in susceptibility to toxic effects. Factors shown to modify the uptake, distribution, biotransformation, or excretion of solvent include physical activity (work load), body composition, age, sex, genetic polymorphism of the biotransformation, ethnicity, diet, smoking, drug treatment, and coexposure to ethanol and other solvents. A better understanding of modifying factors is needed for several reasons. First, it may help in identifying important potential confounders and eliminating negligible ones. Second, the risk assessment process may be improved if different sources of variability between external exposures and target doses can be quantitatively assessed. Third, biological exposure monitoring may be also improved for the same reason.

Improvement in the gastrointestinal absorption of troglitazone when taken with, or shortly after, food

AIMS

Troglitazone, an insulin action enhancing agent, is currently in clinical development for the treatment of non insulin dependent diabetes mellitus. The objective of this study was to establish the effect of food on the systemic absorption and metabolism of troglitazone.

METHODS

After an overnight fast, 12 healthy male volunteers each received, in random order, troglitazone (400 mg orally) alone, concomitantly with (at the start of), and 30 min after, a standardized diabetic breakfast as part of a three-period crossover study.

RESULTS

When troglitazone was administered with or after food, geometric mean values of area under the plasma concentration-time curves (AUC[last]) relative to fasting state were increased significantly by 59% in both cases (95% CI 1-150%, P=0.046 and 2-148%, P=0.040) with values of 11.4, 11.5 and 7.2 microg ml(-1) h respectively. Maximum observed plasma concentration (Cmax) increased by 96% and 72% (95% CI 29-197%, P=0.003 and 15-158%, P=0.011) with values of 2.2, 2.0 and 1.1 microg ml(-1) respectively. Changes in t(lag) were not clinically significant. Increases in AUC(0, infinity) for the main circulating sulphate metabolite relative to fasting were also significant (41%, 95% CI 5-89%, P=0.025 and 34%, 95% CI 1-79%, P= 0.044 respectively) with values of 82.6, 78.6 and 58.5 microg h ml(-1). Cmax increased by 68% (95%, CI 10-156%, P=0.019) and 65% (95% CI 9-149%, P=0.020) with values of 3.2, 3.1 and 1.9 microg ml(-1) respectively. Reductions in t1/2 (16 and 21%, 95% CI 0-30, 6-33) although statistically significant (P=0.050 and P=0.009) were not clinically significant with values of 22.3, 20.4 and 24.5 h for with food, after food and fasting respectively. Troglitazone was well tolerated in all cases throughout the study with a trend for improved tolerability of gastrointestinal symptoms when taken 30 min after a meal.

CONCLUSIONS

The absorption of troglitazone is enhanced significantly by food with little effect on the main metabolic pathway. Increased absorption of troglitazone in the presence of food is likely to be a consequence of enhanced solubility in bile combined with an increase in dissolution time. On the basis of these findings, troglitazone should be taken either with, or up to 30 min after, food.

Drug-nutrient interactions in three long-term-care facilities

OBJECTIVE

To assess the risk of drug-nutrient interactions (DNIs) in three long-term-care facilities.

DESIGN

Retrospective audit of charts.

SETTING

Three long-term-care facilities in central New York State.

SUBJECTS

Fifty-three patients selected randomly from each facility.

MEASUREMENT

Data were collected from the medical record of each patient for a period of 6 months. A computerized algorithm was used to assess the risk for DNIs. Mean drug use, most frequently consumed drugs, incidence of potential DNIs, and the most commonly observed potential DNIs are reported.

RESULTS

In facilities A, B, and C, respectively, patients consumed a mean of 4.86, 4.04, and 5.27 drugs per patient per month and were at risk for a mean of 1.43, 2.69, and 1.43 potential DNIs per patient per month. The most commonly observed potential DNIs were gastrointestinal interactions affecting drug bioavailability and interactions affecting electrolyte status.

CONCLUSIONS

Patients in long-term-care facilities, who are primarily elderly and chronically ill and who consume multiple medications, are at notable risk for certain DNIs. Efforts need to be made to ensure appropriate pharmacologic and nutrition therapies as well as adequate and timely monitoring of patients in these facilities. Dietitians can play an important role in training other health professionals and in designing policies to prevent DNIs.

Attitudes of healthcare professionals toward patient counseling on drug-nutrient interactions

OBJECTIVE

To evaluate the attitudes of healthcare providers on drug-nutrient interaction (DNI) counseling.

DESIGN

A mail survey.

SETTING

Random sample of healthcare providers with interest in nutrition, practicing in Iowa or Nebraska.

METHODS

A 48-item questionnaire was constructed on the basis of a review of DNI literature. The survey was sent to 100 pharmacists, 50 registered dietitians, 25 registered nurses, and 25 physicians identified from culled mailing lists of the American Society of Parenteral and Enteral Nutrition and the Iowa Nebraska Society of Parenteral and Enteral Nutrition. Assessed variables included the amount of DNI counseling provided, who is in the best position to provide DNI counseling, and what information should be included in instructional materials on DNIs for patients. Data were entered into a relational database for evaluation and comparison.

RESULTS

The usable response rate was 49.5 percent (n = 99): 49 pharmacists, 29 dietitians, 18 nurses, and 3 physicians. Only 12 respondents provided DNI counseling in > 50 percent of patient interactions. Seventy-one respondents (72 percent) felt pharmacists were in the best position to discuss DNIs with patients. More than half of the respondents felt a new DNI pamphlet should be developed to replace an existing Food and Drug Administration-sponsored pamphlet. Although 70 percent felt the new pamphlet should be organized according to specific drugs, many felt the format should also include specific populations and disease states. Eighty-six percent indicated that a chart on DNIs geared toward healthcare professionals would be useful.

CONCLUSIONS

Patient-oriented resources should be developed to enhance DNI counseling. Pharmacists are in a uniquely advantageous position to provide DNI counseling.