Effects of alprazolam on respiratory drive, anxiety, and dyspnea in chronic airflow obstruction: a case study.

Alprazolam, an anxiolytic benzodiazepine, has a pharmacologic profile similar to that of diazepam. An intermediate half-life of 10-12 hours and a comparatively brief duration of activity relative to other anxiolytic benzodiazepines justified evaluation of a 0.5-mg test dose in an anxious patient with chronic obstructive lung disease. Subjective indexes, breath-by-breath respiratory drive response to hypercapnia, and blood alprazolam concentrations were determined before and after dosing. Subjective testing included a visual analog dyspnea scale, the state anxiety inventory, and subjective feelings visual analog scales (represented by alertness, calmness, and level of contentment). After dosing, the patient was better able to tolerate the rebreathing study technique. Statistically significant improvements in dyspnea (t - 10.20; p 0.0005), anxiety (t - 45.85; p less than 0.0001), alertness (t - 13.04; p less than 0.0001), cententedness (t - 12.27; p less than 0.0001), and calmness (t - 8.05; p less than 0.0001) occurred after alprazolam administration. Drive to breathe, as determined by mouth occlusion pressure and minute ventilation, was not statistically different before and after dosing. No adverse effects were reported or observed. Further study is warranted.

Patient tolerance to intravenous potassium chloride with and without lidocaine.

Hypokalemia is a common electrolyte abnormality. Intravenous repletion therapy with potassium chloride (KCl) in concentrations greater than 80-100 mEq/L is not recommended due to patient intolerance. Since this guideline at times may be clinically impractical, this study was designed to examine use of peripheral vein infusions of high concentration KCl therapy. Tolerance to KCl 20 mEq/65 ml iv with and without lidocaine 50 mg was evaluated in 18 hypokalemic subjects in a randomized, placebo-controlled, double-blind study. Subjective and objective assessments of adverse effects were determined throughout the infusion period. Pain was assessed by both verbal descriptor and visual analog scales and correlated significantly following infusion of KCl with or without lidocaine. Multivariant analysis demonstrated differences in pain perception between solutions, with significantly less pain following KCl with lidocaine versus KCl infusions. Transient adverse effects occurred in both groups, but the incidence was not statistically different. Use of concentrated iv KCl infusions may benefit hypokalemic patients with hypervolemia and/or severe potassium deficits. Addition of lidocaine clearly improves patient tolerance to intravenous KCl replacement.

Evaluation of therapeutic drug monitoring in a long-term care facility: a pilot project.

The need for a therapeutic drug monitoring service was evaluated in a 150-bed long-term care facility. Thirty blood samples from 28 residents (mean age 87.9 years) were assayed to determine trough drug concentrations. All subjects were examined to determine pharmacodynamic effect. Pharmacokinetic consultations were written for serum drug concentrations outside accepted ranges. Fifty percent (15 of 30) of serum drug levels measured were subtherapeutic; the remaining levels were in the normal therapeutic range. Based on this sample data, it could be concluded that a minimum of 32 percent and as many as 68 percent of serum drug levels would be subtherapeutic following drug analysis in similar nursing home populations. Of 12 consultations, recommendations for seven (58 percent) were accepted by the subject's primary care physicians. Four of the consultations (33 percent) resulted in dosage modifications. These results support the need for further study.

Human infection with herpes zoster: etiology, pathophysiology, diagnosis, clinical course, and treatment.

Herpes zoster is a cutaneous vesicular eruption resulting from recrudescence of the chickenpox virus. It is mainly a disease of adults, with a predisposition for the elderly or immunocompromised. Although usually localized, the disease can disseminate to visceral organs. Diagnosis is often made based on the characteristic pattern of the lesion and clinical features. Tzanck smear, viral isolation, seroconversion, antibody titers, and monoclonal antibodies may further aid or confirm the diagnosis. Clinical features of herpes zoster may follow a progression through 3 stages, prodromal, acute, and chronic. The prodromal and acute phases seldom require more than symptomatic management. The chronic pain syndrome, postherpetic neuralgia (PHN), demands a more aggressive approach. Pharmacologic intervention, neuroaugmentation, and/or surgery may prevent or alleviate PHN, but universal response to any of these therapeutic approaches is unlikely. Tricyclic antidepressants remain the first choice in treating this pain syndrome. A trial of antiviral therapy may be warranted in patients with disseminated disease or in immunocompromised patients with localized disease. Of the antiviral agents, acyclovir is considered the drug of choice by most clinicians.

Evaluation of creatinine clearance estimation in an elderly male population.

Thirty-one medically stable, elderly males (age 75 +/- 8.3 yrs) participated in a prospective study evaluating the accuracy of 16 methods of estimating creatinine clearance. Serum creatinine values were determined on the mornings of days 1, 4, and 5 to assure stable renal function. On the morning of day 3, a 24-hour urine collection was initiated. A statistically significant correlation existed between the measured and estimated clearance values for all 16 formulas. The correlation (r less than 0.65) was lower than that in previously published studies, however. Five of the formulas (1A, 5A, 5B, 7A, 7B) demonstrated no statistical difference between mean measured and estimated values. In this population, formula 2B was the least biased and formula 9B the most accurate. For all 16 methods, the bias was minimal and the relative accuracy of the estimated methods was comparable. The results support using methods to estimate creatinine clearance only as a rough bedside prediction of renal function in elderly males.

Continuous nasogastric morphine infusion.

Morphine sulfate is the narcotic analgesic most commonly used for pain treatment in terminally ill patients. This case report demonstrates a new method of morphine administration. A 56-year-old terminally ill cancer patient with severe pain from metastatic adenocarcinoma of the lung required continuous nasogastric feeding and around-the-clock narcotic analgesics. The patient was safely and effectively converted from a continuous intravenous morphine infusion to continuous nasogastric morphine-enteral feedings. This method of administration may benefit patients receiving continuous enteral tube feedings who either require high-dose morphine therapy or are unable to use the oral administration route.

Pharmacogeriatrics.

The elderly comprise one of the fastest growing populations in the United States. By the year 2020, an estimated 45 million will be classified as elderly. Aging is a highly variable process as declines occur in physiologic functions. Alterations in cardiovascular, renal and hepatic function have the greatest effect on drug therapy. All pharmacokinetic and pharmacodynamic variables may be altered by age. Adverse drug reactions, drug interactions and poor compliance are frequent and may further complicate drug therapy. A review of those processes that commonly influence pharmacologic response and patient compliance to drug therapy is appropriate.