Effect of terbinafine on theophylline pharmacokinetics in healthy volunteers

Twelve healthy volunteers were enrolled in an open-label, randomized, crossover study. Subjects received single doses of theophylline (5 mg/kg) with and without multiple-dose terbinafine, and 11 blood samples were collected over 24 h. The study phases were separated by a 4-week washout period. Theophylline serum data were modeled via noncompartmental analysis. When the control phase (i.e., no terbinafine) was compared to the treatment phase (terbinafine), theophylline exposure (the area under the serum concentration-time curve from time zero to infinity) increased by 16% (P = 0.03), oral clearance decreased by 14% (P = 0.04), and half-life increased by 24% (P = 0.002). No significant changes in other theophylline pharmacokinetic parameters were evident.     

Effects of red wine on 24-hour esophageal pH and pressures in healthy volunteers

The purpose of this study was to assess the effects of red wine taken with meals on esophageal motility, esophageal exposure to acid, and gastric pH. Following a randomized design, 14 healthy male volunteers (mean age 25 years, range 18-35 years were given 360 ml of red wine or tap water during lunch or dinner. All subjects underwent ambulatory 24-hr esophageal motility and esophagogastric pH monitoring studies. Three different periods were analyzed: during meals (30 min), postprandial (3 hr), and 8-hr supine. Two volunteers complained of heartburn after wine ingestion. An increase in the number of high amplitude waves (> 125 mm Hg, 95th percentile of our motility unit controls) was observed during meals accompanied by wine: water 1.2 (0-10.2), wine 1.6 (0-32.6), P = 0.02 [median (range)]. No other esophageal motility changes occurred. Percent reflux time increased during the postprandial period after wine ingestion in comparison with water: 1.7 (0-14.9) vs 0.1 (0-0.8), P < 0.05. Gastric pH was unaffected by the type of drink. Ingestion of moderate amounts of red wine with meals increases postprandial esophageal exposure to gastric acid in healthy persons.     

Clinical and upper gastrointestinal motility features in systemic sclerosis and related disorders

OBJECTIVE: The aim of this study was to characterize the clinical and motility findings in 62 patients with systemic sclerosis or related disorders referred for evaluation of upper gastrointestinal (GI) symptoms. METHODS: Methods included retrospective clinical record review and quantitation of esophageal, LES antral, and duodenal motility (3 h fasting, 2 h fed) were compared with results of 10 symptomatic patients with normal gastric emptying. RESULTS: A total of 46 patients had systemic sclerosis, eight mixed connective tissue disease, and eight polymyositis-systemic sclerosis overlap; systemic manifestations were almost invariably present. GI symptoms were: heartburn (77%), nausea/vomiting (58%), dysphagia (61%), diarrhea (53%), constipation (31%), and fecal incontinence (13%). Anatomical studies showed esophageal erosions or GERD (53%), aperistalsis (34%), stricture (29%), and Barrett's metaplasia (16%); megaduodenum, small bowel dilation, or diverticulae (42%); and pneumatosis intestinalis (8%). A total of 36 patients underwent esophageal and 26 esophagogastrointestinal manometry. Postprandial antral motility index was abnormal in 22 of 26; amplitudes and frequency in the antrum (34 +/- 3 mm Hg and 0.6 +/- 0.1/min, respectively) and duodenum (7.3 +/- 0.9 mm Hg and 1.8 +/- 0.5/min) were significantly lower than controls (p < 0.05). CONCLUSION: In patients with GI symptoms associated with systemic sclerosis and related disorders, the amplitude and frequency of intestinal contractions are typically <10 mm Hg and <2/min. Antral amplitude is low (<40 mm Hg) when antral hypomotility is observed.     

Effect of acute dietary fibre supplementation on colonic pH in healthy volunteers

Two patients presented with a tumor involving mainly the supplementary motor area or the premotor cortex. Shortly after tumor resection, each developed transient impairment of voluntary movements. An electromyogram, with the skin electrodes placed over the muscles of the upper arms and forearms, demonstrated aberrant ipsilateral, contralateral or bilateral muscle activation during unilateral motor tasks in both patients. The bilateral activation was more prominent in the patient who had an intact dominant hemisphere. The present study suggests for the first time the importance of non-primary motor areas of the human brain in activating the proper set of muscles on the proper side of the body.     

Effect of CI-988 on cholecystokinin tetrapeptide-induced panic symptoms in healthy volunteers

A randomized, placebo-controlled, double-blind, three-way crossover design was used to evaluate the effectiveness of single oral 100 mg doses of CI-988, a cholecystokinin B (CCKB) antagonist, in attenuating panic symptoms induced by intravenous injection of cholecystokinin-tetrapeptide (CCK-4). Thirty healthy men received the following treatments on three separate occasions: placebo capsules/placebo, placebo capsules/CCK-4, or CI-988 capsules/CCK-4. There was no marked difference in the number, time to onset, or duration of panic symptoms between CI-988/CCK-4 and placebo/CCK-4. There was, however, a 14% difference in sum intensity scores between these treatments that was statistically significant (p = 0.039). The symptoms most affected by CI-988 were cold chills/hot flushes, chest pain/discomfort, and anxiety/fear/apprehension. Panic attack frequency also decreased following CI-988 treatment (8/30 vs. 16/30; p = 0.035). This decrease, amid otherwise modest effects, could be explained by a preferential effect of CI-988 on the subjective experience of anxiety/fear/apprehension. Possible reasons for the relatively modest effects of CI-988 on CCK-4-induced panic symptoms are discussed.     

Effects of a new motilide, ABT-229, on gastric emptying and postprandial antroduodenal motility in healthy volunteers

BACKGROUND: ABT-229 is a recently developed derivative of erythromycin, devoid of antibiotic activity. We studied the effect of ABT-229 on gastric emptying and postprandial antroduodenal motility in healthy volunteers. METHODS: Placebo, 4 and 16 mg ABT-229 were given as a single oral dose to nine healthy volunteers, in a randomized, 3-period crossover design. A solid meal (250 kcal) was given twice, 45 min after drug ingestion and 4 h later. Gastric emptying of each meal was studied using the 13C-octanoic breath test. Antroduodenal motility was recorded during the total 9-h period. RESULTS: After the first meal, both the 4 and 16 mg doses increased the gastric emptying rate to a similar extent. ABT-229 stimulated the contractile motility of the antrum dose-dependently. The half-emptying time and the lag-phase of gastric emptying correlated with the number of pressure waves that were propagated over the antrum and the mean amplitude of antral pressure waves. After the second meal no significant effects of ABT-229 were found. CONCLUSIONS: A single dose of the new motilin agonist ABT-229 strongly increases the gastric emptying rate in healthy volunteers by increasing the strength and length of propagation of antral pressure waves. ABT-229 has the potential to become a new prokinetic drug.     

Effect of cisapride and renzapride on gastrointestinal motility and plasma motilin concentration in dogs

The effects of cisapride and renzapride (BRL 24924), on plasma concentration of motilin and gastroduodenal motility were studied in seven dogs with implanted force transducers in the antrum and duodenum. In the interdigestive state, the i.v. administration of cisapride (5 mg) or renzapride (5 mg) administered in phase I resulted in a prompt and marked increase in plasma motilin concentration and in gastroduodenal motility. Mean plasma motilin levels during the first 30 min after cisapride and after renzapride injection were 85.0 +/- 6.5 (+/- S.E.) and 96.1 +/- 6.3 pM., respectively. These values were significantly greater (P < .001) than those for the corresponding time period of the control cycle, 52.2 +/- 5.6 and 57.4 +/- 5.3 pM (mean phase III level, 120 +/- 8.1 pM), respectively. The increases in the motilin level after cisapride or renzapride coincided with significant increases in contractile activities of the antrum to 43.2 +/- 5.3% and 44.9 +/- 4.6% and of the duodenum to 28.4 +/- 3.1% and 34.2 +/- 2.2% of phase III activity (100%) from that in the corresponding control period, 0.7 +/- 0.4% and 0.2 +/- 0.1%, respectively. The changes in both plasma motilin and motility in response to the two drugs were abolished completely by the i.v. administration of atropine. The drugs also enhanced the meal-induced contractile activities of the antrum as well as the duodenum but failed to influence the postprandial plasma motilin concentration. We conclude that cisapride and renzapride have similar effects on plasma motilin and gastroduodenal motility: 1) the two drugs increase plasma motilin levels and stimulate gastroduodenal motility in the interdigestive state, and 2) in the digestive state, both drugs enhance motility without influencing the plasma motilin levels.     

Increase in red blood cell triiodothyronine uptake in untreated unipolar major depressed patients compared to healthy volunteers

1. Kinetic parameters of red blood cell (RBC) L-triiodothyronine (T3) initial uptake (Vmax, maximal velocity and Km, Michaelis constant) were determined in 34 untreated inpatients suffering from unipolar depression and in 40 healthy volunteers. 2. Both Vmax and Km were significantly increased in depressed patients as compared to controls. The alterations in kinetic parameters were not associated with the severity of depression. 3. Out of the 19 depressed patients who were submitted to TRH test, 7 of them (36%) showed a blunted TRH-induced TSH response associated with a Vmax situated outside the control mean value +/- 1 S.D. 4. The authors found a significant positive correlation between Vmax of RBC L-T3 and L-tryptophan (TRP) uptakes which is in agreement with the assumption that L-T3 and L-TRP share a common carrier system at the erythrocyte level. 5. The results indicate that the uptake of L-T3 by RBC is increased in major depression. These transport perturbations might reflect alterations in the plasmatic metabolism of L-T3. Evaluation of RBC L-T3 uptake could be useful in a best biological characterization of the depressed patients with regard to their thyroid function.     

Effects of intravenous ketamine on gastrointestinal motility in the dog

OBJECTIVE: The purpose of this trial was to clarify the effects of intravenous ketamine at anaesthetic and sub-anaesthetic dosages on gastrointestinal motility. DESIGN: 20 beagles (group 1: 3 mg/ketamine/kg/h, n = 10; group 2: 30 mg ketamine/kg/h, n = 10), were investigated. Gastric emptying (nuclide gastric emptying studies, liquid and semi-solid test meal), intestinal transit time (Hydrogen breath test with lactulose) and intestinal motor function (perfusion manometry with 8 measuring ports) were determined. As a control condition, the tests were performed on all dogs in the two groups during infusion of physiological saline solution. RESULTS: No significant differences in the motility patterns were present between 3 mg ketamine/kg/h and the control condition. For group 2, a moderately significant (p < 0.05) increase in the interdigestive motility index was observed for 30 mg ketamine/kg/h. However, this did not change the transit criteria. There was no significant difference between ketamine and control condition tests with regard to cycle and phase lengths or the propagation rate of the activity front. CONCLUSIONS: We conclude that ketamine provokes no basic changes in gastrointestinal motility, at either sub-anaesthetic doses. It can therefore be used to advantage in the continuous postoperative analgesia of intensive care patients, where repeated interventions are necessary and no cardiopulmonary contraindications are present.     

Investigations on the pharmacokinetics of alpha-lipoic acid in healthy volunteers

Recent medical publications postulate a connection between the Chronic Fatigue Syndrome (CFS) and disturbed regulation of the circulation, manifesting itself during orthostatic stress testing. Four studies were published on the circulatory response on prolonged head up tilt testing. Numerous CFS patients displayed postural tachycardia or syncope during the test. However, many CFS patients examined had had orthostatic symptoms prior to the examination. It is not certain that cardiovascular dysregulation is present in CFS patients without orthostatic symptoms. It is also not clear whether such a dysregulation would be the effect of physical inactivity or a manifestation of a subtle form of autonomic neuropathy.     

Effects of low-dose morphine on gastric emptying in healthy volunteers

BACKGROUND: Type 2 diabetes mellitus is a major and increasing cause of morbidity and early mortality among the Aboriginal population of northern Australia. Due to differing social, dietary and probably metabolic factors, management needs differ from the mainstream Australian diabetic population. OBJECTIVE: This paper concentrates on the options for oral therapy in the control of glycaemia, taking into account various current guidelines and recent trials of oral antihyperglycaemic therapy, and the specific metabolic and clinical associations with type 2 diabetes mellitus in this population. DISCUSSION: In the abscence of specific contraindications, and in variance with some present guidelines, the evidence suggests that initial therapy with metformin rather than the sulphonylureas is likely to provide greater clinical benefit, and have a greater margin of safety.     

Effects of lorazepam on film-induced differentiated emotions in healthy volunteers

We studied the effects of lorazepam, a benzodiazepine, on differentiated emotions in healthy volunteers. In order to induce differentiated emotions, film excerpts were selected on the basis of the type of emotion they induced (fear, anger and for affective tone neutral film). For 6 days (D1 to D6), ten healthy volunteers received lorazepam (1 mg bid) or placebo in a randomized cross-over double-blind trial. During each treatment period, emotional induction occurred on D4, D5 and D6. One film excerpt (fear, anger or neutral) was presented each morning after relaxation. Evaluation was performed before and after each emotional induction and included questionnaires (Differential Emotions Scale and physical activation visual analog scales), and neurophysiological parameters (systolic and diastolic blood pressure, heart rate and norepinephrine levels). Globally, the film excerpts induced the predicted emotions. An analysis of variance was undertaken and revealed a significant effect of lorazepam versus placebo. On the Differential Emotions Scale and during fear induction, lorazepam induced a significantly higher increase in fear, anxiety and disgust emotions than placebo, whereas no effect was observed after anger induction. Lorazepam also induced a significantly higher increase in diastolic and systolic blood pressure with no change in heart rate, and physical activation items ("tears" and "faster breathing") without no significant change in norepinephrine. In conclusion, our results are consistent with an overall increase in emotional reactivity with lorazepam (1 mg bid) as compared to placebo. The pertinence of film-induced differentiated emotions has to be confirmed for clinical pharmacological use.     

Impact of smoking cessation on salivary function in healthy volunteers

BACKGROUND: Salivary bicarbonate and epidermal growth factor (EGF) have an important protective role in the oesophagus. The effect of smoking cessation on these aspects of salivary function is unknown. METHODS: Salivary bicarbonate secretion and EGF output were measured before and after attempted smoking cessation in 28 healthy volunteers. Urinary cotinine excretion was used to assess compliance. RESULTS: Negative correlations were found between salivary flow rate and age (rho = -0.34) and between cigarette consumption and salivary flow (rho = -0.27) and salivary bicarbonate concentrations (rho = -0.32). Smoking cessation was associated with a significant increase in salivary bicarbonate secretion (day 0, 1.7 (0.14-6.2); day 7, 3.6 (0.52-6.4); day 21, 3.3 (0.44-6.6) micromol min(-1); P < 0.01) but left salivary EGF output unchanged. CONCLUSION: Smoking cessation is associated with significant improvements in salivary bicarbonate secretion. This would benefit patients with reflux disease who stop smoking.     

Steady-state pharmacokinetic properties of pramipexole in healthy volunteers

Pramipexole is a dopamine receptor agonist that has proved effective in the treatment of Parkinson's disease. The pharmacokinetic properties of pramipexole at steady-state concentrations were studied in 16 healthy men and women at four dose levels throughout the range recommended for Parkinson's patients. Plasma and urine samples collected within the four dose intervals were assayed for concentrations of pramipexole, using high-performance liquid chromatography. The total oral clearance for all participants was 419 mL/min. The mean volume of distribution and elimination half-life for all participants was 486 +/- 93.2 L and 12.9 +/- 3.27 hours. Concentrations of pramipexole were proportional to dose, although the drug's pharmacokinetic properties differed between men and women. The area under the concentration-time curve for each dose level was 35% to 43% greater in women, mainly because of a 24% to 27% lower oral clearance. The mean creatinine clearance in men and women was 112 +/- 12.8 mL/ min/1.73 m2 and 80.9 +/- 15.6 mL/min/1.73 m2, respectively. The renal clearance of pramipexole accounts for approximately 80% of oral clearance, and there was a significant correlation between renal and creatinine clearances. The influence of gender could not be distinguished from the influence of age and the resulting reduced creatinine clearance, but the measurement of pharmacokinetic properties produced linear results in both men and women.     

Effects of terbinafine on the pharmacokinetics of digoxin in healthy volunteers

STUDY OBJECTIVE: To assess the potential effects of terbinafine, a new synthetic allylamine antifungal agent, on the pharmacokinetics of a single 0.75-mg oral dose of digoxin. DESIGN: Randomized, double-blind, placebo-controlled, crossover study consisting of two treatment periods. SUBJECTS: Sixteen healthy men and women volunteers. INTERVENTIONS: During treatment A, placebo was administered once/day for 12 days; during treatment B, terbinafine 250 mg was administered orally once/day for 12 days. The washout period between treatments was at least 2 weeks. A single 0.75-mg oral dose of digoxin was administered on day 8 of each period. Blood samples were collected after administration of digoxin to determine pharmacokinetics. MEASUREMENTS AND MAIN RESULTS: Compared with placebo, terbinafine did not alter the time course of the digoxin serum levels. Although the time to maximum peak concentration with terbinafine was slightly reduced, the maximum concentration and area under the serum drug concentration-time curve from time zero to 120 hours were not significantly different with terbinafine than with placebo. No drug-related side effects were reported with either active treatment, and no clinically significant changes in vital signs, physical examination results, electrocardiograms, or clinical laboratory results were observed. CONCLUSIONS: No special dosage adjustments for digoxin appear to be necessary during concomitant therapy with terbinafine.     

Effect of tolcapone on plasma levodopa concentrations after coadministration with levodopa/carbidopa to healthy volunteers

Tolcapone (Ro 40-7592) is a novel inhibitor of catechol-O-methyltransferase that is being developed for clinical use in the treatment of Parkinson's disease as add-on therapy to a combination of levodopa and a peripheral amino acid decarboxylase inhibitor (benserazide or carbidopa). The current single-blind, randomized study was designed to evaluate the effect of tolcapone compared with placebo on plasma levodopa concentrations in healthy volunteers concomitantly receiving 25 mg of carbidopa and 100 mg of levodopa (Sinemet 25-100) and to assess the tolerability and safety of this combination. Placebo or tolcapone at doses of 5, 10, 25, 50, 100, 200, 400, and 800 mg was coadministered orally with Sinemet 25-100. Each dose was tested in a crossover fashion in a new group of six participants who each received active drug on one occasion and placebo on the other. Tolcapone increased the area under the plasma concentration-time curve and half-life of levodopa approximately twofold, without appreciably increasing the peak concentration. The maximum effect on levodopa half-life was observed with the 200-mg dose. Adverse effects were minor at all doses.     

Metabolic disposition of 14C-bromfenac in healthy male volunteers

The metabolic disposition of 14C-bromfenac, an orally active, potent, nonsteroidal, nonnarcotic, analgesic agent was investigated in six healthy male subjects after a single oral 50-mg dose. The absorption of radioactivity was rapid, producing a mean maximum plasma concentration (Cmax) of 4.9 +/- 1.8 microg x equiv/mL, which was reached 1.0 +/- 0.5 hours after administration. Unchanged drug was the major component found in plasma, and no major metabolites were detected in the plasma. Total radioactivity recovered over a 4-day period from four of the six subjects averaged 82.5% and 13.2% of the dose in the urine and feces, respectively. Excretion into urine was rapid; most of the radioactivity was excreted during the first 8 hours. Five radioactive chromatographic peaks, a cyclic amide and four polar metabolites, were detected in 0- to 24-hour urine samples. Similarity of metabolite profiles between humans and cynomolgus monkeys permitted use of this animal model to generate samples after a high dose for structure elucidation. Liquid chromatography/mass spectrometry (LC/MS) analysis of monkey urine samples indicated that the four polar metabolites were two pairs of diastereoisomeric glucuronides whose molecular weight differed by two daltons. Enzyme hydrolysis, cochromatography, and LC/MS experiments resulted in the identification of a hydroxylated cyclic amide as one of the aglycones, which formed a pair of diastereoisomeric glucuronides after conjugation. Data also suggested that a dihydroxycyclic amide formed by the reduction of the ketone group that joins the phenyl rings formed the second pair of diastereoisomeric glucuronides. Further, incubation of various reference standards in control (blank) urine and buffer with and without creatinine indicated that the hydroxy cyclic amide released from enzyme hydrolysis can undergo ex vivo transformations to a condensation product between creatinine and an alpha-keto acid derivative of the hydroxy cyclic amide that is formed by oxidation and ring opening. Further experiments with a dihydroxylated cyclic amide after reduction of the keto function indicated that it too can form a creatinine conjugate.