Bioavailability and pharmacokinetics of lorazepam after intranasal, intravenous, and intramuscular administration.

The purpose of this study was to evaluate the pharmacokinetic profile of intranasal lorazepam in comparison to currently established administration routes. Eleven healthy volunteers completed this randomized crossover study. On three occasions, each separated by a 1-week washout, subjects received a 2 mg dose of lorazepam via the intranasal, intravenous, or intramuscular route. Blood samples were collected serially from 0 to 36 hours. Noncompartmental methods were used to determine pharmacokinetic parameters. Lorazepam was well absorbed following intranasal administration with a mean (%CV) bioavailability of 77.7(11.1). Intranasal administration resulted in a faster absorption rate than intramuscular administration. Elimination profiles were comparable between all three routes. The concentration-time profile for intranasal delivery demonstrated evidence of a double peak in several subjects, suggesting partial oral absorption. Females were found to have significantly higher AUC values than males for all three delivery routes. Overall, this study demonstrated favorable pharmacokinetics of intranasal lorazepam in relation to standard administration methods. Intranasal delivery could provide an alternative, noninvasive delivery route for lorazepam.

Pharmacokinetics of flunisolide administered via metered dose inhaler with and without a spacer device and following oral administration.

BACKGROUND: After inhalation of a glucocorticoid from a meter dose inhaler (MDI), a certain portion of the delivered dose is deposited in the lungs, and the remainder is deposited in the oropharynx. OBJECTIVE: To examine the absolute bioavailability of flunisolide given orally via metered dose inhaler, and metered dose inhaler with a commercially available spacer device as well as to determine the fraction of drug deposited in the lungs following inhalation. METHODS: Twenty-four healthy volunteers were enrolled in the study; twenty-two completed the study. The IRB approved the study protocol, and informed consent was obtained. Volunteers received four treatments: treatment A (MDI), 1.0 mg inhaled flunisolide; treatment B (MDI-S), 1.0 mg inhaled flunisolide with a spacer device; treatment C, 1.0 mg of orally administered flunisolide with 240 mL of water; and treatment D, 1.0 mg intravenous flunisolide by IV push in the antecubital vein over 60 seconds. Plasma and urine flunisolide were quantified by HPLC/mass spectrometry/mass spectrometry. RESULTS: Flunisolide is a corticosteroid with low oral bioavailability (6.7%), which was found to be lower than previously reported. Similar AUCs were observed between the MDI and MDI-S groups, but by using mass balance equations, it appears that more flunisolide was delivered to the lungs in the MDI-S group (410 microg versus 280 microg). Oropharyngeal deposition was an important difference between the two inhaler groups. Approximately an 11-fold reduction in the oropharyngeal deposition of flunisolide through use of the spacer device was observed. CONCLUSIONS: Use of a spacer device improved pulmonary delivery of flunisolide by almost 50% and significantly decreased the oropharyngeal exposure to drug.

Clinical research: regulatory issues.

The regulatory issues faced by institutions performing clinical research are described. Many institutions do not have on staff an expert who understands the regulatory issues involved in managing investigational new drug research and who knows the institution's obligations under the federal rules. Because pharmacists understand the FDA regulations that apply to the management of drugs in clinical research, institutions are asking pharmacists to expand their role and manage clinical research offices. Many authorities govern various aspects of investigational drug research. FDA has published regulations for good clinical practice (GCP), and the International Conference on Harmonisation is developing an international standard for the proper management of clinical trials. The guidelines published by the Joint Commission on Accreditation of Healthcare Organizations aim to protect patients who are in the institution to receive health care and also participate in clinical trials. The Social Security Administration Acts specifically state that only items and services that are reasonable and necessary for the diagnosis and treatment of injury or disease can be billed to the government; research-related billings are excluded from coverage. Proper management of drug research is crucial to the success of a research program that is integrated with patient care.

Seizures in patients receiving concomitant antimuscarinics and acetylcholinesterase inhibitor.

Seizures occurred in two patients with probable Alzheimer's disease who were receiving long-term treatment with metrifonate, an irreversible acetylcholinesterase inhibitor. In both patients seizures were associated with discontinuation of short-term agents with high antimuscarinic properties. Hence, abrupt discontinuation of antimuscarinics or anticholinergics with high antimuscarinic properties in patients receiving long-term acetylcholinesterase inhibition therapy may be associated with a reduction of seizure threshold. With increasing administration of acetylcholinesterase inhibitors for patients with Alzheimer's disease, practitioners should be aware of the potential for drug-drug interactions and other complications. In general, it is good medical practice to avoid concomitant administration with centrally acting anticholinergic agents.

Pharmacokinetics, pharmacodynamics, and safety of metrifonate in patients with Alzheimer's disease.

Metrifonate is converted nonenzymatically to 2.2, dimethyl dichlorovinyl phosphate (DDVP), an inhibitor of acetylcholinesterase (AChE). This 21-day, randomized, double-blind, placebo-controlled trial of metrifonate in patients with Alzheimer's disease (n = 27) evaluated four doses, each administered orally once daily. All patients received a loading dose (LD) for 6 days followed by a maintenance dose (MD) for 15 days. The treatment groups were: panel 1, LD = 1.5 mg/kg (75-135 mg), MD = 0.25 mg/kg (12.5-25 mg); panel 2, LD = 2.5 mg/kg (125-225 mg), MD = 0.40 mg/kg (20-35 mg); panel 3, LD = 4.0 mg/kg (200-335 mg), MD = 0.65 mg/kg (30-60 mg); and panel 4, LD = 4.0 mg/kg (200-335 mg), MD = 1.0 mg/kg (50-90 mg). All metrifonate doses were well tolerated. Most adverse events were mild to moderate in intensity, gastrointestinal in nature, and transient. Mean area under the concentration-time curve (AUC) and maximum concentration (Cmax) for both metrifonate and DDVP increased in relation to dose. Metrifonate and DDVP had similar, largely dose-independent mean values for time to Cmax (tmax) and half-life (t1/2). There was little or no accumulation of either metrifonate or DDVP with long-term administration. After 21 days of treatment, mean percent erythrocyte AChE inhibition was 14%, 35%, 66%, 77%, and 82% for placebo and panels 1 through 4, respectively. Cognitive improvement was observed with the two highest metrifonate doses. These results reflect favorable safety and pharmacokinetic profiles for the use of metrifonate in the treatment of Alzheimer's disease.

Gender-related considerations in clinical pharmacology and drug therapeutics.

The pharmacokinetics and pharmacodynamics in women are different from that in men because of women's unique anatomy and physiology. Recently, gender-related studies in clinical pharmacology have been emerging, supporting the observation of gender-induced variations in drug response. The hormonal fluctuations during a woman's life span may influence pharmacotherapy. Therefore, gender-related pharmacology should be taken into consideration when prescribing medication for a woman. Data from drug developmental studies, FDA approved label directions, and other clinical research evaluation women's responses to medications are necessary to make optimal pharmacotherapeutic decisions.

Frontal lobe phosphorus metabolism and neuropsychological function in aging and in Alzheimer's disease.

31P Magnetic resonance spectroscopy of the frontal lobe was performed in 17 patients with Alzheimer's disease (AD), 8 elderly controls (EC), and 17 young controls (YC). The phosphocreatine/inorganic phosphate (PCr/Pi) ratio in AD (2.32 +/- 0.26 SD) was significantly lower than in EC (2.65 +/- 0.41). In AD patients, a correlation was observed between the PCr/Pi ratio and the dementia rating scale (r = -0.50, p = 0.04). A significant positive correlation between PCr/Pi ratio and age was observed in both AD (r = 0.67, p = 0.003) and YC (r = 0.63, p = 0.006) groups, however, suggesting caution in interpretation of this ratio in AD. We did not find differences between AD, EC, or YC in any other spectroscopic measure. A significant sex difference in the phosphomonoester/phosphodiester ratio (PME/PDE) ratio was observed in AD brain. Females had a lower PME/PDE ratio than males.

Dirithromycin increases ethinyl estradiol clearance without allowing ovulation.

OBJECTIVE: To use a novel, sensitive study design to detect a potential oral contraceptive (OC) and dirithromycin drug interaction by assessing the pharmacokinetics of the ethinyl estradiol (E2) component of a common OC and the potential failure of OC effectiveness. METHODS: In this nonblinded study, 20 healthy women using Ortho Novum 7/7/7-28 were selected for a three-OC-cycle study. Baseline measures included E2 and progesterone serum levels on days 21, 23, 25, and 27 of cycle one and days 1, 3, 5, and 7 of cycle two. During cycle two, 24-hour blood sampling and radioimmunoassay analysis for ethinyl E2 pharmacokinetics were performed on day 8 and pelvic ultrasound on day 13. Oral dirithromycin 500 mg/day for 14 days began on day 21 of cycle 2. After starting dirithromycin, cycle two and three serum E2, progesterone, and serial ethinyl E2 levels and pelvic ultrasound replicated the baseline schedule. Ovulation was assumed if E2 concentration was greater than 50 pg/mL, progesterone concentration was greater than 3 ng/mL, or if an ovarian cyst greater than 10 mm was present on ultrasound. RESULTS: Pharmacokinetic analysis demonstrated a small (7.6%) but statistically significant decrease (P = .03) in the mean ethinyl E2 24-hour area under the curve and an increase in apparent oral clearance. No woman ovulated, based on E2 levels and progesterone concentrations or ultrasound. CONCLUSION: Dirithromycin increased the apparent oral clearance of ethinyl E2. The clinical importance of the interaction may be negligible because no woman ovulated or had compromised OC effectiveness in this small series.

Single oral dose fluconazole compared with conventional clotrimazole topical therapy of Candida vaginitis. Fluconazole Vaginitis Study Group.

OBJECTIVES: Candida vaginitis is currently treated with a wide range of intravaginal preparations usually prescribed over several days. Fluconazole with its marked activity against Candida species and favorable pharmacokinetics offered a safe, effective, and convenient alternative to topical therapy in a single-dose regimen. STUDY DESIGN: We conducted a multicenter, randomized, prospective, single-blinded study of 429 patients with acute Candida vaginitis, comparing the efficacy and safety of a single oral 150 mg dose of fluconazole with 7-day clotrimazole 100 mg vaginal treatment. Posttherapy evaluations and mycologic eradication rates were conducted. RESULTS: No statistically significant differences were seen between fluconazole and clotrimazole in the clinical, mycologic, or therapeutic responses. At the 14-day evaluation clinical cure or improvement was seen in 94% of fluconazole-treated patients and 97% of clotrimazole-treated patients. Mycologic and therapeutic cures were seen in 77% and 76% of the fluconazole and 72% of the clotrimazole groups, respectively. At the 35-day evaluation 75% of both groups remained clinically cured, and 56% of the fluconazole and 52% of the clotrimazole group were considered therapeutic cures. In both treatment groups patients with a history of recurrent vaginitis (33/84) compared with those without a history of recurrent vaginitis (177/266) were significantly less likely to respond clinically and mycologically (p < 0.001). Twenty-seven percent of the fluconazole-treated patients and 17% of the clotrimazole-treated patients reported mild side effects only. CONCLUSION: Fluconazole administered as a single 150 mg oral dose proved to be as safe and effective as 7 days of intravaginal clotrimazole therapy for Candida vaginitis. Therapy of vaginitis should be individualized, taking into consideration severity of disease, history of recurrent vaginitis, and patient preference.

Effects of long-term oral carvedilol on the steady-state pharmacokinetics of oral digoxin in patients with mild to moderate hypertension.

The effect of multiple oral doses of carvedilol on steady-state plasma digoxin pharmacokinetics was evaluated in 12 patients with mild to moderate hypertension. Area under the curve (AUC), mean maximum plasma concentration (Cmax), mean time to maximum concentration (Tmax), concentration at 24 hours after the dose (C24), creatinine clearance, renal digoxin clearance, and urinary digoxin excretion were determined after patients took oral digoxin 0.25 mg once/day for 2 weeks. Carvedilol was added to the regimen, and digoxin pharmacokinetics were assessed after 2 weeks of concurrent treatment. The AUC and Cmax for digoxin increased by 14% and 32%, respectively (p < 0.05), with no change in Tmax. The 24-hour urinary digoxin excretion and 24-hour renal digoxin clearance increased by 45% and 26%, respectively (p < 0.05), with no change in creatinine clearance. Carvedilol appears to increase digoxin's oral bioavailability as well as renal elimination. The absolute change in digoxin pharmacokinetics was small and not clinically significant. The significance of the interaction in other patient populations remains to be studied.

A dose-response study of orally administered torsemide in patients with ascites due to cirrhosis.

BACKGROUND: This study evaluated the dose-response relationship of torsemide, the first pyridine-sulphonylurea loop diuretic, in patients with ascites due to cirrhosis. METHODS: During a 13-day hospitalization period, 17 patients received single, oral doses of 5 mg, 10 mg, or 20 mg of torsemide or placebo in a randomized, double-blind, crossover fashion. All the patients received a constant dose of spironolactone concomitantly beginning at least 7 days before the study. Electrolyte excretion and urine volume were measured for 24 h after each dose. Body weight was measured before, and 24 h after each dose. RESULTS: Torsemide was effective in producing statistically significant, dose-related increases in urinary sodium and chloride excretion, with little effect on potassium or magnesium excretion. Urine volume increased and body weight decreased in a dose-related manner. CONCLUSION: Torsemide increased sodium excretion substantially in patients with cirrhosis and ascites who were receiving spironolactone.

Pharmacodynamics of racemic and S(-)-atenolol in humans.

The cardiovascular actions of racemic atenolol (RSATN) have been well characterized in humans, but the actions of S(-)-atenolol (SATN) when administered alone are unknown. In this study, responses of heart rate (HR) and Doppler-derived aortic blood flow profiles to upright treadmill exercise were compared after oral administration of 50 mg SATN and 100 mg RSATN in eight healthy, adult, male volunteers. After a single-blind, placebo run-in period, subjects were randomly allocated in a double-blind, crossover fashion to receive SATN and RSATN. Each study period was separated by a 7-day washout period. Multiple submaximal exercise tests were performed and data were collected over the 24 hours after each treatment. Both SATN and RSATN significantly (P < .05) blunted peak exercise HR by 38 +/- 3 and 37 +/- 3 beats/min, respectively. Aortic blood flow acceleration measured during peak exercise decreased after SATN and RSATN, by 13 +/- 4 and 13 +/- 3 m/sec2, respectively (P < .05). No difference in hemodynamic effect was observed between treatments. Pharmacodynamic parameters derived from plasma S(-)-atenolol concentration-effect (HR) curves after SATN, RSATN, and total atenolol plasma concentrations after RSATN did not differ significantly. Predicted maximum reductions in heart rate (Emax) and EC50 for S(-)-atenolol after SATN were 39.6 +/- 5.8 beats/min and 38.4 +/- 40.9 ng/ml versus 34.5 +/- 8 beats/min and 25.9 +/- 29.9 ng/ml for RSATN, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer-assisted investigational drug information and testing mechanism for nurses.

The Joint Commission on Accreditation of Healthcare Organizations and the American Society of Hospital Pharmacists state that nurses should not administer investigational drugs to patients unless they can prove knowledge about the medication. Traditionally this obligation was met when the pharmacy provided nurses with investigational drug data sheets or access to computer files containing similar information. Our department of pharmacy was cited at a recent JCAHO inspection as being unable to show that nurses were knowledgeable about the investigational medications they were administering. The reviewer requested testing documents prepared by the pharmacy and completed by nursing staff showing the nurses' proficiency with investigational drug information. In response to the JCAHO inspection, the department of pharmacy proposed a quality assurance mechanism to provide investigational drug information and to determine nurses' comprehension and application of these data before they administer any investigational drug. Use of a hospital mainframe computer system to disseminate investigational drug information and test nurses is described.

Pharmacokinetics and pharmacodynamics of a new cardiotonic vasodilator agent, 349U85, in normal subjects.

OBJECTIVE: To assess the pharmacodynamics and pharmacokinetics of single oral doses of a new vasodilator-cardiotonic agent, 349U85 hydrochloride [6-piperidino-2(1H)-quinolinone hydrochloride], in healthy male subjects. METHODS: This randomized, parallel, double-blind, placebo-controlled, dose escalation trial was conducted at a university-based clinical research center among 27 healthy male subjects. Data measurements used in the study included cardiac index, supine and standing blood pressure, 24-hour ambulatory electrocardiography, and 12-lead electrocardiography. RESULTS: Doses from 2 mg to 250 mg were well tolerated. Cardiac index, supine heart rate, and orthostatic hypotension, indicators of inotropic, chronotropic, and vasodilator effects, respectively, correlated to plasma concentrations of 349U85 and of its metabolite, 661U88. Results suggest that 349U85 may be more responsible for inotropic effects, whereas 661U88 may be more responsible for vasodilatory and chronotropic effects. These results are consistent with the preclinical pharmacologic profile for these two compounds. Headache, orthostatic dizziness, and hypotension tended to occur more frequently at higher doses and were temporally related to drug administration. Pharmacokinetic analyses indicate nonlinearity of 349U85 and 661U88, suggestive of saturation of metabolism and large interindividual variability in maximum plasma drug concentration and area under the plasma concentration-time curve. The source of the variability is not known. The time to maximum distribution was approximately 0.7 hours for both 349U85 and 661U88; the terminal elimination half-life was 1 hour for 349U85 and 3 hours for 661U88. Holter monitoring revealed asymptomatic increases in ventricular and supraventricular ectopic activity in some volunteers; ectopy appeared to be related to the dose of 349U85 and generally occurred at higher doses.

Current issues surrounding women and minorities in drug trials.

OBJECTIVE: Our principal objective is to make readers aware of conflicting demands placed on investigators and the pharmaceutical industry regarding inclusion of women and minorities in clinical research. Tremendous pressures have been placed to expedite the drug approval process. Moreover, during the last decade certain segments of society, particularly women and minorities, have demanded greater participation in clinical drug trials and earlier access to investigational drug therapies. Regulations that have served the clinical research community (pharmaceutical industry, investigators, institutional review boards) as guidelines for safe conduct of human clinical trials are being challenged by social and political change. This article provides an overview of some of the controversy relative to federal regulations governing clinical trials; scientific concerns; social, political and legal trends; and ethical principles applied to human clinical research. DATA SOURCES: Literature for this paper was retrieved from a variety of sources including the nonmedical press, editorials, peer-reviewed journals, Department of Health and Human Services regulations, National Institutes of Health policy, the Belmont Report, and regulations of the Food and Drug Administration. DATA SYNTHESIS: Scientists evaluating new therapeutic agents ask specific research questions to assess safety, efficacy, and the mechanism(s) of action. Because of concerns for scientific validity, safety, liability, and convenience, many early evaluations of new drugs involve patient populations that may not represent the ultimate users of a new drug. Federal regulations and ethical principles allow certain groups of people to be excluded from early research proposals because they are thought to be putting themselves at greater risk by participating than are other groups. However, women, minorities, and other populations are demanding greater access to investigational drugs. The focus has changed from protection from research risks and burdens to the potential benefits a person or class of people may obtain by participating in a study. CONCLUSIONS: Scientists, the pharmaceutical industry, regulators, and society must agree on a safe and efficient mechanism for new drug development that permits more equitable participation of subjects in the various phases of research.

Patient-controlled analgesia using butorphanol for postoperative pain relief: an open-label study.

Patient-controlled analgesia (PCA) has been studied extensively for the treatment of postoperative pain using narcotic analgesics. Butorphanol, a nonnarcotic injectable analgesic, has not previously been investigated using this drug delivery mechanism. Twenty-five patients undergoing general abdominal surgery and general anesthesia used a PCA device with butorphanol as the analgesic agent. Most patients (84%) were able to obtain excellent postoperative pain relief. The role of butorphanol in the management of postoperative pain should be expanded to include patient-controlled drug delivery.

Drug delivery for intractable cancer pain. Use of a new disposable parenteral infusion device for continuous outpatient epidural narcotic infusion.

Administration of narcotic analgesics through the epidural route has proven useful for treating pain of acute and chronic nature. This route of narcotic administration is frequently chosen for cancer patients with intractable pain that may be refractory to treatment by conventional oral or parenteral therapy. Implantable constant infusion devices have been commonly described as an alternative drug delivery system for this type of patient. This case report describes the use of the Travenol Infusor (Travenol Laboratories Inc., Deerfield, Illinois) an external, lightweight, disposable, drug delivery device for delivering continuous epidural morphine infusion to a patient with severe cancer pain. The patient has achieved stable pain relief for greater than 8 months without hospital admission for pain control, or management of complications due to the drug delivery system. The Travenol Infusor may prove to be an alternative drug delivery system for patients requiring continuous epidural narcotic infusion.