Fluctuations of lipid and lipoprotein levels in hyperlipidemic postmenopausal women receiving hormone replacement therapy

BACKGROUND

Fluctuations in lipid and lipoprotein levels are encountered quite often in hyperlipidemic patients. We examined the possibility that lipid and lipoprotein levels fluctuate due to the different effects of estrogen and progestogen in postmenopausal hyperlipidemic women receiving combined hormonal replacement therapy.

METHODS

In an open-label study conducted during 3 consecutive hormonal cycles (3 months), levels of fasting total cholesterol, triglycerides, and low (LDLC)- and high-density lipoprotein cholesterol (HDLC) were determined in 36 postmenopausal hyperlipidemic women on day 13 of conjugated equine estrogen (1.25 mg/d) therapy and on day 25 after 12 days of receiving estrogen plus medroxyprogesterone acetate (5 mg/d).

RESULTS

While receiving estrogen and combined therapies, means +/- SD total cholesterol levels increased from 6.50 +/- 0.97 mmol/L (251 +/- 37 mg/dL) to 6.88 +/- 1.42 mmol/L (266 +/- 54 mg/dL) (P<.001); LDLC levels, from 4.05 +/- 1.14 mmol/L (156 +/- 44 mg/dL) to 4.62 +/- 1.36 mmol/L (178 +/- 52 mg/dL) (P<.001). Mean +/- SD HDLC cholesterol levels decreased from 1.44 +/- 0.32 mmol/L (55 +/- 12 mg/dL) to 1.29 +/- 0.28 mmol/L (50 +/- 10 mg/dL) (P<.001); triglyceride levels, from 2.23 +/- 1.03 mmol/L (197 +/- 91 mg/dL) to 2.06 +/- 1.04 mmol/L (182 +/- 92 mg/dL) (P<.001).

CONCLUSIONS

Hyperlipidemic postmenopausal women receiving combined sequential estrogen and progestogen replacement therapy demonstrate very significant fluctuations in their lipid and lipoprotein levels. These fluctuations depend on the hormonal phase, ie, estrogen alone or combined with progestogen.

Exercise-induced aortic flow parameters in early postmenopausal women and middle-aged men

OBJECTIVE

Exercise Doppler echocardiography has been recognised as an accurate method for the assessment of left ventricular function in patients with coronary artery disease. Gender differences in aortic flow parameters during exercise have not been well established. The aims of this study were to compare basal ejection Doppler indexes in healthy early postmenopausal women with those of men, and to assess the effects of both isometric and dynamic exercises on these parameters.

DESIGN

Intergroup comparison between early postmenopausal women and middle-aged men.

SUBJECTS

Fifteen healthy women with a mean age of 55 (SD 5) years and 15 healthy men aged 52 (SD 4) were evaluated.

SETTING

Women were recruited from a menopause clinic and men from a primary cardiovascular prevention program at a cardiac rehabilitation institute.

INTERVENTIONS

Isometric exercise was performed with a 2-hand bar dynamometer, and dynamic exercise with a supine ergometer. Echo Doppler examination was performed at rest and at peak isometric and dynamic exercise with a pulsed Doppler transducer.

RESULTS

Both types of exercise resulted in higher values of hemodynamic parameters in the women, with most figures reaching statistical significance. Most aortic flow parameters during rest and exercise were also significantly higher in the women.

CONCLUSIONS

The unexpected higher values in hemodynamic and aortic flow parameters in early postmenopausal women as compared with middle aged men may shed light on a peculiar aspect of gender differences in cardiovascular function, perhaps specific to this age group and related to menopausal transition.

Comparative central nervous system effects and pharmacokinetics of neu-metoclopramide and metoclopramide in healthy volunteers

Metoclopramide, a drug used for the relief of nausea and emesis, is currently under development as a radio- and chemosensitizing agent. Its usefulness in high doses, however, is limited by its central nervous system side effects. Neu-metoclopramide (Neu-Sensamide), a novel, concentrated, phosphate-buffered, pH-adjusted (pH = 6.5-7.0) formulation of metoclopramide, has been shown to have an improved side-effect profile in animal studies. The present double-blind, four-way crossover study compared the central nervous system effects and pharmacokinetics of neu-metoclopramide (intravenously and intramuscularly at 1.8 mg/kg) with intravenous metoclopramide and intramuscular placebo in 19 healthy male volunteers. Eight participants withdrew from the study, one because of noncompliance and seven because of adverse events. A total of 28 central nervous system events were observed with intravenous metoclopramide administration, whereas 16, 15, and 6 such events were attributed to intravenous neu-metoclopramide, intramuscular neu-metoclopramide, and placebo, respectively. Extra-pyramidal effects occurred on 10 occasions: 7 after intravenous metoclopramide, 2 after intravenous neu-metoclopramide, and 1 after intramuscular neu-metoclopramide. No significant differences were observed in the pharmacokinetic profiles of the three formulations of metoclopramide. It may be speculated, therefore, that the molecular conformational changes inherent to neu-metoclopramide result in a reduced side-effect profile compared with conventional metoclopramide formulations.

Exercise echocardiography in postmenopausal hormone users with mild systemic hypertension

Rest and exercise echocardiography (at dynamic and isometric exercise) were performed in 30 postmenopausal women (aged 54 +/- 4 years) with borderline to mild hypertension. They were then divided into 2 groups: 17 women who started oral hormone replacement therapy (0.625 mg/day conjugated estrogens or 2 mg/day estradiol) and a control group of 13 nonusers. After 6 to 9 months, a second echocardiography was performed in 26 women (4 withdrew). There were only a few changes in values obtained in the 12 controls at the end of follow-up compared with baseline. Primarily, these changes included a slight decrease in systolic blood pressure at rest and on exercise. Several significant morphologic and hemodynamic alterations appeared in 14 hormone users. Left ventricular cavity dimensions and mass became smaller: mean end-diastolic diameter decreased from 45.9 +/- 3 mm at baseline to 44.4 +/- 3 mm at study termination (p = 0.007). The corresponding values for end-systolic diameter were 25.8 +/- 4 mm and 23.9 +/- 4 mm (p = 0.006); for left atrium diameter, it was 34.5 +/- 4 mm and 32.5 +/- 4 mm (p = 0.001); for left ventricular wall width, it was 19.9 +/- 2 mm and 19.3 +/- 2 mm (p = 0.02); for left ventricular mass, it was 197 +/- 28 g and 179 +/- 32 g (p = 0.006). The resting aortic blood flow velocity and acceleration increased: 119 +/- 18 cm/s before therapy versus 129 +/- 23 cm/s while on hormone substitution (p = 0.04), and 13.6 +/- 3 m/s2 versus 16.5 +/- 4 m/s2 (p = 0.008), respectively. Mean rest to peak exercise systolic blood pressure difference became smaller after hormones: 39 +/- 19 mm Hg versus 28 +/- 13 mm Hg (p = 0.03) during dynamic exercise, and 43 +/- 22 mm Hg versus 25 +/- 13 mm Hg (p = 0.004) during isometric exercise. The above data probably indicate that with hormone replacement therapy, there is an improvement in cardiac function both at rest and during exercise.

Prescribing pattern of antihypertensive drugs in the community

The selection of the most appropriate therapy for hypertension remains a controversial issue. Little information is available regarding the prescribing patterns of antihypertensives in the primary care setting in Israel. The use of antihypertensives in 200 patients of the Maccabi Health Fund was, therefore, examined from April to June 1994. Sixty-four per cent of patients received monotherapy and 36% combination therapy. The most commonly prescribed medication for monotherapy were angiotensin-converting enzyme (ACE) inhibitors (33.6%), followed by beta-blockers (28.1%) and calcium channel antagonists (26.6%). Diuretics were prescribed to 7.0% of the patients. Analysis of overall drug utilization showed that diuretics were used in 21.5% of patients, beta-blockers in 39.5%, calcium channel blockers in 46% and ACE inhibitors in 40% of patients. Despite the growing evidence of the benefits of diuretics and beta-blockers, our results show a low utilization of these agents in comparison to other countries. It may be speculated that the lack of national guidelines, the absence of utilization reviews by third party providers as well as differences in patient population and climate conditions may all contribute to the current prescribing habits of physicians in the Israeli community.

Clearance of chylomicron remnants in normolipidaemic patients with coronary artery disease: case control study over three years

OBJECTIVE

To test the hypothesis that subjects who clear chylomicron remnants slowly from plasma may be at higher risk of coronary artery disease than indicated by their fasting plasma lipid concentrations.

DESIGN

Case control study over three years.

SETTING

An 800 bed general municipal hospital.

SUBJECTS

85 normolipidaemic patients with coronary artery disease selected prospectively and matched with 85 normolipidaemic subjects with normal coronary arteries on angiography.

INTERVENTIONS

All subjects were given a vitamin A fat loading test which specifically labels intestinal lipoproteins with retinyl palmitate.

MAIN OUTCOME MEASURE

Postprandial lipoprotein metabolism.

RESULTS

The area below the chylomicron remnant retinyl palmitate curve was significantly increased in the coronary artery disease group as compared with the controls (mean 23.4 (SD 15.0) v 15.3 (8.9) mumol/l.h; 95% confidence interval of difference 4.37 to 11.82).

CONCLUSION

Normolipidaemic patients with coronary artery disease had significantly higher concentrations of chylomicron remnants in plasma than normolipidaemic subjects with normal coronary vessels. This may explain the mechanism underlying the susceptibility to atherosclerosis of coronary artery disease patients with normal fasting lipid values. As diet and drugs can ameliorate the accumulation of postprandial lipoproteins in plasma, the concentration of chylomicron remnants should be measured in patients at high risk of coronary artery disease.

Low-dose thiazides in the treatment of hypertension: benefits and risks in perspective

Diuretics in low doses are very effective agents for controlling hypertension either where used alone or in combination. They have a marked cardioprotective effect, are the best tolerated of any anti-hypertensives and are at the same time the least expensive.

Comparisons of beta-adrenergic blocking properties of S- and R-timolol in humans

In animals, the R-enantiomer of timolol causes a significant reduction in intraocular pressure but had only 1/80 the activity of the S-enantiomer at extraocular receptors. The beta 1- and beta 2-adrenoceptor blocking properties of orally administered R- and S-timolol were compared in a double-blind placebo controlled trial in two groups of healthy men. Each subject in group A (n = 6) received placebo, 1 and 3 mg S-timolol and 25 and 75 mg R-timolol in random order, group B (n = 5) received placebo, 0.5, and 1 mg S-timolol and 3 and 10 mg R-timolol. In both groups, R- and S-timolol comparably inhibited isoproterenol-induced increases in heart rate (P < .05), forearm blood flow (P < .05, except at 3 micrograms/minute of isoproterenol after the R-doses in group B), and finger tremor (P < .05) in comparison with placebo. The findings for the R-enantiomer in this study were unexpected based on the animal studies and previous studies that demonstrated marked differences in beta blocking effects of other beta-blockers in which the R-enantiomers were less inhibitory.

Distribution of ciprofloxacin in ascitic fluid following administration of a single oral dose of 750 milligrams

The penetration of ciprofloxacin into the ascitic fluid of eight patients was studied. Serum and ascitic fluid samples were obtained before and at 1, 2, 3, 6, and 12 h following administration of a single oral dose of 750 mg. Peak levels (mean +/- standard deviation) were 4.0 +/- 0.7 micrograms/ml in serum and 2.6 +/- 0.6 micrograms/ml in ascitic fluid; the areas under the curve (0 to 12 h) were 29.1 +/- 6.5 micrograms.h/ml in serum and 20.7 +/- 5.0 micrograms.h/ml in ascitic fluid. The concentrations that were achieved are well above the MICs of ciprofloxacin for the members of the family Enterobacteriaceae that cause spontaneous bacterial peritonitis.

Characterization of sarcoplasmic reticulum in skinned heart muscle cultures

The plasma membranes of rat heart muscle, grown in cell culture, were made permeable with saponin in a Ca-free solution. The cells were then supplied with a medium resembling the cytosol, and the adenosine triphosphate (ATP)-dependent Ca2+ sequestration was measured in the presence of oxalate. The nonmitochondrial component accounts for about 50% of the total Ca2+ uptake. The nonmitochondrial accumulation of Ca2+ within myocardial cells was found to be reversible by addition of the Ca2+ ionophore A23187. On the other hand, the Ca2+ antagonist D-600 (50 microM) had almost no effect on Ca2+ accumulation. Caffeine reduced Ca2+ accumulation in the skinned cardiomyocytes in a concentration-dependent manner. In addition, the anticalmodulin drug trifluoperazine (TFP) reduced Ca2+ accumulation in the skinned cells. Because of the analogy between nonmitochondrial ATP-dependent Ca2+ accumulation and the sarcoplasmic reticulum (SR) function with regard to the influence of various agents, it is assumed that we actually measure Ca2+ accumulation in the SR. The rate of Ca2+ accumulation into the SR measured during the development of the cardiomyocytes in culture shows an almost linear increase as a function of culture age. Amiodarone, a potent antiarrhythmic agent, and its metabolite, desethylamiodarone, inhibited Ca2+ accumulation into SR, which may explain their therapeutic effect.

Varied presentations of sporadic group A streptococcal bacteremia: clinical experience and attempt at classification

The epidemiologic, clinical, and laboratory aspects of group A streptococcal bacteremia were studied in 33 patients seen at two urban hospitals in the Tel Aviv (Israel) area, over an 8-year period. Most patients (two-thirds) were female. Clinically significant bacteremia was observed in 26 patients, two of whom acquired their infection (puerperal sepsis) during hospitalization. A portal of entry, mainly cutaneous, was recognized in 61% of the patients, and a chronic underlying condition was observed in 69%. The case-fatality rate was 27%, with death occurring predominantly in patients admitted with shock or cryptogenic bacteremia. Our clinical experience and literature review show that the presentation of group A streptococcal bacteremia is diverse, with transient bacteremia of uncertain clinical significance on one end of the spectrum and overwhelming sepsis on the other. A practical classification of the various clinical forms of group A streptococcal bacteremia is proposed.

Effect of repeated doses of L-5-hydroxytryptophan and carbidopa on prolactin and aldosterone secretion in man

To evaluate changes in serum prolactin and plasma and urine aldosterone after a serotonergic challenge, 8 healthy men (19 to 42 yr), taking dexamethasone (0.75 mg qid), received the serotonin precursor L-5-hydroxytryptophan (L5HTP; 100 mg qid) with the peripheral decarboxylase inhibitor carbidopa (C; 50 mq qid) or matching placebos in a randomized, crossover manner. Serum prolactin concentration increased in all subjects after L5HTP/C in comparison to placebo, mean (SD) prolactin (ng/ml) at 8 h after dosing was 19.8 +/- 6.3 after L5HTP/C and 12.0 +/- 3.1 after placebo (p less than 0.05). In contrast, in comparison to values on placebo, L5HTP/C had no apparent effect on mean plasma concentration at all observation times; mean (SD) aldosterone (ng/dl) at 8 h after dosing was 12.0 +/- 5.1 and 12.0 +/- 3.8 after placebo (NS). Mean (SD) urinary aldosterone (micrograms/24 h), Na+(mEq/24 h) and K+(mEq/24 h) excretion were 7.0 +/- 4.4, 49.3 +/- 30.6, 30.1 +/- 11.2, after L5HTP/C and 7.4 +/- 5.8, 59.7 +/- 23.9, 33.3 +/- 7.4 after placebo (NS). Under these study conditions, subacute serotonergic stimulation with oral L5HTP/C resulted in prolactin but not aldosterone release.

Angiotensin-converting enzyme inhibitors

There is convincing evidence that ACE inhibitors, alone or in combination with a diuretic, effectively lower blood pressure in patients with all grades of essential or renovascular hypertension and that they are of particular benefit as adjunctive therapy in patients with congestive heart failure. The hemodynamic, hormonal and clinical effects of the presently available ACE inhibitors, captopril and enalapril, are comparable and their side effect profiles are extremely favorable. One important difference between the two oral ACE inhibitors, however, is their pharmacokinetics; enalapril's action is slower to begin and is of longer duration. Compared with other agents, ACE inhibitors offer important advantages, among them an improved feeling of well being. It is, therefore, expected that ACE inhibitors will gain greater acceptance by patients and physicians in the future.

Amiodarone in the management of cardiac arrhythmias: current concepts

This article reviews current information on the clinical pharmacology, therapeutic utility, and adverse reactions of amiodarone, with emphasis on guidelines for its rational use.

Amiodarone therapy: role of early and late electrophysiologic studies

Forty-two patients with a history of symptomatic ventricular tachycardia or cardiac arrest underwent electrophysiologic testing at control and early in the course of amiodarone therapy (mean 12 +/- 7 days). Late electrophysiologic studies (mean 17 +/- 4 weeks) were repeated in 23 patients on a maintenance dose of 400 mg/day. At control study, all patients had inducible ventricular tachyarrhythmias (sustained ventricular tachycardia in 35, nonsustained ventricular tachycardia in 4, ventricular fibrillation in 3), while after amiodarone loading (1,200 mg daily) 4 (10.5%) of the 42 patients developed noninducible ventricular arrhythmias. At late study, an additional 6 (26%) of the 23 patients with inducible arrhythmias at early study developed noninducible arrhythmias. The cycle length of induced ventricular tachycardia increased from 275 +/- 61 ms at control study to 340 +/- 58 ms at early study (p = 0.001). A further increase in ventricular tachycardia cycle length was noted in patients who underwent both early and late study (341 +/- 38 versus 375 +/- 63 ms, p less than 0.05). The percent of induced tachycardias that were clinically tolerated increased as patients were treated longer with amiodarone (control = 22%, early = 34%, late = 53%, p less than 0.001). Of the 23 patients who had both early and late electrophysiologic studies and were followed up for a mean of 21.7 months (range 4 to 47), there were no recurrences among the 6 patients with noninducible arrhythmias, but there were five recurrences among the 17 patients with persistently inducible arrhythmias. None of the four patients with noninducible arrhythmias at early study had a recurrence. On the basis of these findings, it is concluded that: 1) The timing of programmed electrical stimulation will affect the results of the study in patients treated with oral amiodarone.(ABSTRACT TRUNCATED AT 250 WORDS)

Cancer family syndrome of Lynch

This report describes a family in whom eight cancers (six colonic and two endometrial) occurred in seven relatives. The colonic cancer was diagnosed in five of the six affected patients at an unusually young age, had a predilection for the proximal colon, and was of the mucinous type in four patients. Polyposis was not found in any colon. The occurrence of cancer in this kindred is characteristic of the "cancer family syndrome" of Lynch.

Management of cardiac arrhythmias during pregnancy. Current concepts

Cardiac arrhythmia is one of the most common reasons for cardiac consultation during pregnancy. Fortunately, malignant arrhythmias during the course of normal gestation are rare, and the relatively common complaint of palpitations is usually due to benign arrhythmias. However, in pregnant patients with organic heart disease, arrhythmias are often triggered by the haemodynamic burden of pregnancy and may be the first manifestation of the disease. In addition, rhythm abnormalities in patients with limited cardiac reserves may have significant haemodynamic consequences and can compromise fetal well-being. Any woman who presents with rhythm disorders during pregnancy should undergo a diagnostic evaluation to rule out an underlying disease, including cardiac, pulmonary, endocrine, or metabolic disease. Additionally, removal of precipitating factors, such as excessive ingestion of caffeine and/or alcohol, cigarette smoking, drug abuse or therapy with arrhythmogenic compounds, is indicated (as these measures are desirable in any pregnant woman). Antiarrhythmic drug therapy is indicated in such patients only in symptomatic or haemodynamically significant arrhythmias. In cases where organic heart disease or any other cause for arrhythmia is identified, the underlying disease should be treated first. Antiarrhythmic drug therapy is indicated when arrhythmias persist or as a prophylactic measure. In principle, the approach to drug therapy in pregnant patients is similar to that in non-pregnant patients. However, special consideration should be given to drug selection in order to avoid adverse effects to the fetus. Those antiarrhythmics that have been shown to be relatively safe during pregnancy include digoxin, quinidine, procainamide, some beta-blocking drugs and lignocaine (lidocaine). In addition to careful drug selection, the smallest effective dose should be used and the indication for antiarrhythmic therapy should be periodically reassessed during the course of pregnancy.

Lack of effect of multiple doses of cimetidine on estimated hepatic blood flow

Conflicting data exists regarding the effect of the H2-receptor blocking agent cimetidine on hepatic blood flow (HBF). The variance in the results of these studies may be due in part to differences in the duration of cimetidine administration, the posture of the volunteers during their course of study, and the method used to estimate HBF. To assess the effects of chronic cimetidine (300 mg q.i.d. X 4 days) on estimated HBF while controlling posture (supine and standing), a double-blind, placebo-controlled, repeated measures study was performed in 9 healthy males. Indocyanine green (ICG) plasma clearance after an i.v. dose of 0.5 mg kg-1 was used to calculate HBF. ICG plasma concentrations were measured by HPLC. Compared to placebo treatment, cimetidine had no effect on mean (SD) estimated HBF (ml min-1 m-2) in either the supine (497 (64) vs 494 (80] or the standing (443 (117) vs 404 (89] posture. These data had a power greater than 0.8 to detect a treatment effect of 20 per cent. Standing produced a significant decrease in estimated HBF (496 (70) vs 424 (102); p less than 0.01). In contrast to previous reports, chronic cimetidine treatment had no apparent effect on hepatic blood flow.

Double-blind comparison of captopril and enalapril in mild to moderate hypertension

To compare the antihypertensive and humoral effects of the angiotensin-converting enzyme inhibitors captopril and enalapril, 20 patients with essential hypertension, not receiving treatment for 2 weeks and consuming a prescribed sodium ion intake, were randomly assigned to two parallel, double-blind treatment groups with stratification based on race and untreated seated diastolic blood pressure. These groups received a placebo (day -1) followed by either captopril, 200 mg every 12 hours (n = 9), or enalapril maleate, 20 mg every 12 hours (n = 11), alone (days 1 to 14) and then with hydrochlorothiazide, 25 mg every 12 hours (days 16 to 28). Captopril and enalapril were coadministered alone (day 15) and with hydrochlorothiazide (day 29) to assess whether further decreases in blood pressure would occur. Captopril and enalapril alone caused comparable decreases (p less than 0.05) in the mean 12 hour time-averaged seated diastolic blood pressure from values on day -1 (placebo), on day 1 (11 and 9 mm Hg, respectively) and day 14 (8 and 7 mm Hg, respectively). The addition of hydrochlorothiazide further decreased (p less than 0.05) blood pressure in each group (7 and 8 mm Hg, respectively) from values on day 14. Combined use of captopril and enalapril did not result in further reduction. Coupled with the comparable changes observed in each treatment group in serum angiotensin-converting enzyme activity, plasma renin activity and plasma aldosterone concentration, these data support the view that captopril and enalapril have similar antihypertensive effects and mechanisms.

A dose-titration trial of guanadrel as step-two therapy in essential hypertension

The efficacy and safety of low-dose guanadrel sulfate were evaluated in 20 patients with essential hypertension based on seated diastolic blood pressures (SDBP) ranging from 95 to 115 mm Hg despite a trial dosage of hydrochlorothiazide 50 mg/d for up to five weeks. These patients had been resistant to, or intolerant of, one or more step-two antihypertensive drugs in the past (i.e., methyldopa, beta-adrenergic blocking agents, clonidine, or prazosin). The majority of patients demonstrated a satisfactory response (SDBP 95 mm Hg or reduction in SDBP of 10 mm Hg) to guanadrel. Nine patients responded at a low dosage, 10 to 20 mg/d and remained free from adverse effects throughout the study (up to 12 weeks of treatment). Of the remaining 11 patients titrated to higher dosages of guanadrel (30 to 60 mg/d), three had no discernible response while six developed adverse effects. The results of the study suggest that guanadrel has an acceptable benefit-to-risk ratio only when used in low dosages (10 to 30 mg/d) and may be successfully employed as step-two antihypertensive therapy in patients resistant to, or intolerant of, other step-two agents.

Initial evaluation of transdermal timolol: serum concentrations and beta-blockade

The serum concentrations and beta-blockade after dermal application of timolol ointment were evaluated in six healthy men (21-31 years old; 74-82 kg). Two patches (25 cm2) containing placebo and either 30 (n = 2) or 60 mg (n = 4) timolol base were randomly applied to the chest for 30 h. Serial serum concentrations of timolol were measured by a radioligand receptor assay. Bicycle ergometry, at a predetermined workload, was performed before and at 3, 8, 24, and 48 h after patch application; mean +/- SD heart rates (beats/min) at these times were 167 +/- 2, 158 +/- 7, 125 +/- 7, 120 +/- 5, and 150 +/- 5 (last 3 values: p less than 0.05 from pretreatment), and beta-blockade was evident in all subjects. Measurable serum concentrations in the therapeutic range were achieved in all subjects. The change in exercise-induced heart rate (y) was closely related to log timolol serum concentration (x) (y = -36 X - 5.3; r = -0.92; p less than 0.001). Based on the amount of timolol in the residual ointment, 50-60% of the original timolol dosage was delivered from the patch. Skin irritation under the patch compared with placebo was minimal. Further studies are warranted to assess the potential clinical utility of transdermal timolol.

Sulindac and ibuprofen inhibit furosemide-stimulated renin release but not natriuresis in men on a normal sodium diet

We compared the effect of two commonly prescribed nonsteroidal anti-inflammatory drugs, ibuprofen and sulindac, and placebo on intravenous furosemide-induced natriuresis and renin stimulation in 11 healthy male volunteers, consuming a 100 mEq sodium, 80 mEq potassium diet. Chronic (6-day) therapy with each agent was followed by a 1-week washout period. There were no significant treatment-related differences in either urine volume or sodium excretion for any of the designated collection periods or for the cumulative value for the 4 h after furosemide administration. Similarly, differences among groups were not observed for creatinine clearance, urinary potassium and urinary chloride excretion. Mean basal plasma renin activity levels prior to furosemide administration on day 6 were significantly lower in the presence of ibuprofen (1.5 +/- 2.0 ng/ml/h;p less than 0.01) and sulindac (2,3 +/- 0.9 ng/ml/h; p less than 0.05), compared with placebo (3.3 +/- 1.1 ng/ml/h); the difference between the two NSAIDs was also significant (p less than 0.05). Mean plasma renin activity levels in the 4 h after furosemide increased significantly at all time points in comparison to basal values, but were significantly less for ibuprofen and sulindac groups in the first hour. Our data suggest that the natriuresis following intravenous furosemide in men consuming a normal sodium intake is not prostaglandin-dependent. Furthermore, the observation that sulindac suppressed basal and stimulated plasma renin activity levels, albeit to a lesser extent than ibuprofen, questions the claim that sulindac "spares' the kidney and compels further evaluation of this issue.

Effect of captopril and hydrochlorothiazide on the response to pressor agents in hypertensives

The effect on arterial pressure of incremental doses of norepinephrine (2 to 10 micrograms/min) and angiotensin II (50 to 800 ng/min) administered over 10 min periods was studied in sodium-replete hypertensive patients after crossover oral treatments with placebo, captopril 50 mg in a single dose, captopril 50 mg three times daily for one week and hydrochlorothiazide 50 mg daily for a week. Neither captopril nor hydrochlorothiazide affected the dose response to infusions of angiotensin II. In comparison to placebo responses, however, both single and multiple-dose captopril therapy, and hydrochlorothiazide attenuated the pressor responses to infusions of norepinephrine. Captopril significantly depressed angiotensin converting enzyme activity from pre-dose levels and angiotensin II infusions significantly elevated plasma aldosterone concentrations. These results confirm findings reported for single dose captopril in normotensive volunteers and indicate that attenuation of the vascular responsiveness to sympathetic stimulation may contribute to the antihypertensive effects of captopril and hydrochlorothiazide therapy.

Relationship of morphine-induced miosis to plasma concentration in normal subjects

The relationship between morphine plasma concentration and pupil diameter was evaluated 2-10 h following intravenous administration of morphine sulfate (10 mg). Seven healthy male volunteers received 10 mg of morphine intravenously following pretreatment for 4 d with either cimetidine (300 mg po four times a day) or placebo in a single blind, balanced crossover study. Pupil diameters were measured directly from contact prints using calipers and a photographed millimeter scale. Cimetidine pretreatment had no significant effect on pupil size either before or after morphine administration or on morphine pharmacokinetics. The relationship between morphine plasma concentration (2-10 h postdose) and pupil diameter was evaluated from the pooled data from both morphine treatment periods by perpendicular least-square regression. In each individual, a strong relationship existed between morphine plasma concentrations and pupil diameter (r = -0.76 to -0.91; p less than 0.05). Weaker correlations for both pupil diameter (r = -0.65; p less than 0.0001) and the absolute change in pupil diameter from baseline (r = 0.72; p less than 0.0001) for the grouped data probably reflect intersubject variation in morphine sensitivity. Thus, the miotic response to an intravenous dose of morphine varies in proportion to morphine plasma concentration.

Steady-state serum amiodarone concentrations: relationships with antiarrhythmic efficacy and toxicity

The relationship of apparent steady-state serum concentrations of amiodarone and its metabolite, desethylamiodarone, to therapeutic and toxic effects was assessed in 127 patients who had treatment-resistant ventricular or supraventricular arrhythmias or were intolerant to other agents. After at least 2 months (mean, 9.8) of treatment with daily maintenance doses of 200 to 600 mg, arrhythmias were effectively suppressed in 78% of patients. Arrhythmias recurred in 47% of patients with serum amiodarone concentrations of less than 1.0 mg/L, whereas only 14% of patients with higher concentrations had recurrences (p less than 0.005). Side effects, most of them mild, occurred in 57%; only 9 patients required discontinuation of drug therapy. The risk of developing adverse reactions was related to serum amiodarone concentrations (p less than 0.0001). Adverse reactions were common in patients with serum values exceeding 2.5 mg/L, although pulmonary complications did occur at lower concentrations. Monitoring serum amiodarone concentrations may differentiate failure of drug therapy from suboptimal dosing and reduce the incidence of concentration-related side effects.

Clinical applications of angiotensin-converting enzyme inhibitors

Although only recently introduced, angiotensin-converting enzyme inhibitors have been utilized to treat a wide variety of clinical disorders. Their uses to date, approved by the Food and Drug Administration, have been in the treatment of refractory hypertension and congestive heart failure. However, they have been evaluated with mixed results in numerous other conditions in which the renin-angiotensin-aldosterone system may play a role. Their current status in the treatment of hypertension, congestive heart failure, and these other conditions is reviewed.

Indacrinone: natriuretic and uricosuric effects of various ratios of its enantiomers in healthy men

Indacrinone is an investigational loop-acting diuretic. To evaluate the natriuretic and uricosuric effects of varying ratios of its enantiomers, 10 healthy men, on a controlled Na+ (100 mEq) and K+ (80 mEq) diet, participated in a double-blind, randomized, balanced incomplete block, multiple-dose (one week) study of a fixed daily dose (10 mg) of (-) enantiomer combined with increasing doses (40, 90 and 140 mg) of (+) enantiomer versus 50 mg hydrochlorothiazide and placebo. On day 1, mean 24-h urinary Na+ increased (p less than 0.01) comparably (approximately 285 mEq) after each enantiomer combination and hydrochlorothiazide; however, the enantiomer combinations had marked uricosuric and hypouricemic effects that were enhanced with increased (+) enantiomer doses. By day 7, while enantiomer combinations and hydrochlorothiazide demonstrated comparable natriuretic activity, mean serum uric acid levels (mg/dl), in comparison to placebo, were increased (p less than 0.05) with hydrochlorothiazide but progressively decreased with increases in (+) enantiomer. Thus varying the ratio [(+, uricosuric): (-, natriuretic)] of the enantiomers of indacrinone caused natriuresis similar to hydrochlorothiazide, but had an opposite effect on serum uric acid.

Methyldopa does not alter the disposition of digoxin

To investigate whether methyldopa alters digoxin disposition, eight healthy subjects received methyldopa titrated to 250 mg t.i.d. or placebo in a double-blind, cross-over manner for 16 consecutive days, with 0.25 mg intravenous digoxin coadministered on day 5 and 0.25 mg oral digoxin on days 9 to 16. Digoxin concentrations in plasma and urine were measured by RIA. Although assay sensitivity did not allow an adequate assessment of serum AUC(0-infinity) after intravenous administration, mean digoxin AUC(0-24) was 10.2 +/- 3.5 and 10.0 +/- 1.8 ng/ml X hr with placebo and methyldopa, respectively (P greater than 0.05). Mean urinary excretion after digoxin with or without methyldopa treatment was 0.204 +/- 0.34 and 0.197 +/- 0.38 mg, respectively. The mean steady-state serum concentrations of oral digoxin (AUC(0-24)/zeta) with and without methyldopa were 0.65 +/- 0.2 and 0.62 +/- 0.3 ng/ml, respectively. These data revealed no significant differences (P greater than 0.05) for various parameters with power of greater than 0.8 to detect meaningful differences of approximately 30 per cent. Thus, methyldopa did not alter digoxin disposition in healthy subjects, and a pharmacokinetic interaction in patients is unlikely.

Bucindolol, a beta-adrenoceptor blocker with vasodilatory action: its effect in systemic hypertension

Bucindolol is a newly developed, nonselective beta-adrenergic blocking agent with intrinsic sympathomimetic activity and direct vasodilator properties. In 14 patients with mild to moderate essential hypertension, the effects of bucindolol, hydrochlorothiazide and their combination on blood pressure (BP), heart rate (HR) and parameters of the renin-aldosterone system were compared with those after placebo. Bucindolol's antihypertensive effect was evident within the first hour after drug administration, maximal at 2 to 3 hours, and lasted for as long as 12 hours. Compared with placebo values (108 +/- 5 mm Hg), both bucindolol (97 +/- 9 mm Hg) and hydrochlorothiazide (99 +/- 10 mm Hg) alone significantly and comparably reduced the 12-hour averaged standing diastolic BP, with the combination resulting in approximately additive effects (91 +/- 9 mm Hg). Although bucindolol alone did not affect HR, it attenuated the hydrochlorothiazide-induced increase in HR. There was a tendency for bucindolol to decrease plasma renin activity. Except for transient postural hypotension in 2 patients, bucindolol was well tolerated.

Calcium blockers in smooth-muscle disorders. Current status

Calcium-entry blockers have proven efficacy in a variety of cardiovascular disorders. The effects of these agents on ionic calcium fluxes and, thus, on smooth-muscle contraction suggest that several noncardiac conditions involving smooth-muscle dysfunction may be managed with calcium antagonists. Beneficial therapeutic results have been reported in various forms of hypertension and Raynaud's phenomenon. The results of preliminary studies in treating pulmonary hypertension, cerebral arterial spasm, migraine headache, esophageal motility disorders, and myometrial hypercontractile states are encouraging. Carefully designed, large-scale and long-term clinical trials are needed to establish the therapeutic value of calcium-entry blockers in these disorders.

Initial evaluation of the non-sulfhydryl-containing converting enzyme inhibitor MK-521 in hypertensive humans

MK-521 is a new orally active, nonsulfhydryl angiotensin-converting enzyme (ACE) inhibitor. Single doses of 2.5, 5.0, 10.0, and 20.0 mg were administered to nine hypertensive patients alternating with placebo. All doses of MK-521 caused profound suppression of ACE activity for more than 24 h and decreased standing diastolic blood pressure for more than 12 h without changes in pulse rate. Although there was no further reduction in blood pressure with doses above 5.0 mg, the duration of action was prolonged for more than 24 h with the higher doses. Serum MK-521 concentrations increased with dosage, and ACE was inhibited maximally at concentrations above 10 ng/ml. In this initial study, MK-521 was well tolerated and proved to be a potent and long-acting antihypertensive agent.

Antihypertensive efficacy of once daily MK-521, a new nonsulfhydryl angiotensin-converting enzyme inhibitor

The effects of the new nonsulfhydryl-containing oral converting-enzyme inhibitor MK-521 on blood pressure, heart rate, angiotensin-converting enzyme activity, plasma renin activity and plasma aldosterone concentration were assessed in 10 hypertensive patients. After a 2-week no-treatment period, patients received placebo and then 14 days each: MK-521 20 mg once daily, hydrochlorothiazide 50 mg once daily and the latter 2 in combination. During the last day of each treatment, the mean (+/- standard deviation) time-averaged (1- to 12-hour) standing diastolic blood pressure decreased from 106 +/- 8 (placebo) to 95 +/- 10 mm Hg with MK-521, 95 +/- 13 mm Hg with hydrochlorothiazide (p less than 0.05 vs placebo) and 88 +/- 11 mm Hg with the combination (p less than 0.05 vs all other treatments). The antihypertensive effect of MK-521 was maintained 24 hours after dosing. Heart rate did not change significantly after MK-521 treatment. MK-521 caused a marked suppression of converting enzyme activity for over 24 hours; plasma renin activity increased significantly after each active treatment and MK-521 significantly decreased the hydrochlorothiazide-induced elevation of plasma aldosterone concentration. In this short-term trial, MK-521 was well tolerated.

Amiodarone: individualizing dosage with serum concentrations

The purpose of the present report is to review the available pharmacokinetic information on amiodarone with an emphasis on our own experience in monitoring serum amiodarone concentrations. We have found that 400 mg should be the maximal maintenance dose; if that treatment fails, careful addition of other antiarrhythmic agents is preferable over an increase in amiodarone dosage. Serum concentrations below 2.5 mg/L will significantly improve amiodarone's benefit-to-risk ratio.

Plasma platelet products and exercise-induced myocardial ischemia

Peripheral plasma concentrations of PF-4 and TxB2 were measured by RIA in 26 patients who underwent exercise stress testing. In group A (n = 15; age 50 +/- 16, mean +/- S.D.) in whom blood sampling was performed by venipuncture, seven patients had a positive stress test associated with an increase in PF-4 concentrations from 3.3 +/- 1.6 ng/ml to 6.9 +/- 3.6 (mean +/- S.D.); six of them demonstrated a greater than 50% increase in PF-4; and only one of eight with a negative stress test had such an increase. In group B (n = 11; 49 +/- 10 yr), patients also underwent postexercise thallium-201 scanning and blood samples were obtained through an intravenous catheter. These patients consistently demonstrated higher PF-4 values (before exercise 7.5 +/- 3.9 ng/ml; after exercise 11.9 +/- 7.1), regardless of the results of the exercise and thallium studies. TxB2 concentrations were unchanged in both groups. To further evaluate the effect of catheter-collected samples on PF-4, five healthy males had serial concurrent blood sampling in opposite arms via both venipuncture and catheter. Although PF-4 concentrations in venipuncture samples were constant, those collected through the catheter increased as a function of time. On the basis of the findings in group A, enhanced platelet activation appears to be associated with exercise-induced ischemia. The observations in group B and the healthy controls indicated that catheter-collection of samples artifactually increased PF-4 concentrations.

Dimethyl sulfoxide inhibits bioactivation of sulindac

Sulindac, a nonsteroidal anti-inflammatory agent, is converted to a bioactive sulfide metabolite via reversible reduction of its sulfoxide moiety. To test whether DMSO can inhibit conversion of sulindac to its active form, eight healthy men received, in a randomized, crossover manner, 400 mg of sulindac, orally, either alone or 60 min after an oral dose of DMSO (30 ml, 70% solution). After the drug combination, mean plasma concentrations of the sulfide metabolite were significantly lower than in controls at 1.5, 2, 3, 4, and 8 hr after sulindac administration. The mean area under the plasma sulfide concentration-time curve for 0 to 12 hr was 30% (range 7% to 56%) lower after DMSO treatment. This study suggests that DMSO can inhibit metabolism of other sulfoxides in man and may antagonize the therapeutic efficacy of sulindac.

Urinary excretion of prostacyclin and thromboxane A2 metabolites after angiotensin converting enzyme inhibition in hypertensive patients

The contribution, if any, of various prostaglandins to the antihypertensive effects of angiotensin converting enzyme inhibitors (ACEI) is controversial. We studied the effect of the ACEI captopril (CAP) on the urinary excretion of 6-keto-PGF2 alpha (6-KF), the major metabolite of the vasodilatory prostaglandin, prostacyclin, and thromboxane B2 (TxB2), the stable metabolite of the vasoconstrictor TxA2, in 8 patients with essential hypertension after placebo, two weeks of CAP 25 mg t.i.d. alone, and the same dose of CAP in combination with hydrochlorothiazide (HCTZ) 50 mg/day. Mean 6-KF and TxB2 (nmol/8 hr post-dosing, respectively) did not differ significantly with any treatment; the mean ratio of 6-KF/TxB2 was also unchanged. Likewise, the excretion of these prostaglandins was also evaluated after placebo, the ACEI enalapril (ENA) (5 or 10 mg/day), and the combination of ENA and HCTZ in another group of 8 patients with essential hypertension. Mean 6-KF and TxB2 (nmol/24 hr post-dosing, respectively) showed no significant treatment-related differences; the mean ratio was again unchanged. No correlation existed between the magnitude of blood pressure responses with any treatment and either 6-KF or TxB2 excretion. Thus, the antihypertensive action of ACEI, alone or in combination with HCTZ, does not appear to involve alterations in these vasoactive prostaglandins.

Comparative antihypertensive effects of enalapril maleate and hydrochlorothiazide, alone and in combination

Enalapril maleate is an investigational oral prodrug whose hydrolyzed diacid metabolite is a potent angiotensin-converting enzyme inhibitor. Fourteen patients with mild to moderate hypertension were evaluated after receiving placebo, and two weeks of treatment with each of the following: enalapril maleate (20 mg b.i.d.), hydrochlorothiazide (25 mg b.i.d.), and the two in combination. In comparison to placebo, the magnitudes of the blood pressure reduction after enalapril and hydrochlorothiazide alone were comparable. The reduction in blood pressure following enalapril was evident throughout the 12-hour dosing interval. The combination of enalapril and hydrochlorothiazide resulted in a marked further reduction in blood pressure that was greater than that predicted from the responses to the individual drugs (P less than 0.05). Biochemical parameters confirmed inhibition of angiotensin-converting enzyme during enalapril treatment; serum angiotensin-converting enzyme activity proved an excellent monitor of compliance. Enalapril was generally well tolerated. Adverse effects included symptomatic hypotension in three patients when enalapril was first added to hydrochlorothiazide and hyperesthesia of the oral mucosa without a loss of taste in one patient on enalapril. Enalapril maleate alone and especially in combination with hydrochlorothiazide appears to be an effective, well-tolerated converting enzyme inhibitor with at least a 12-hour duration of action.

Extreme sinus bradycardia associated with lithium therapy

Extreme sinus bradycardia and T wave changes are described in a patient receiving lithium therapy. Ischemic heart disease was excluded by the results of radionuclide study and an exercise stress test. The electrocardiographic changes were shown to be related to lithium therapy, as documented by the inverse correlation between heart rate and plasma lithium levels.

Antiarrhythmic drug therapy during pregnancy

Pregnancy increases the work demands on the heart by increasing blood volume and thereby cardiac output. Therefore, in pregnant patients with organic heart disease, arrhythmias may have significant hemodynamic consequences to the mother with harm to the fetus. As a result of improved medical therapy, an increasing number of women with cardiac diseases or rhythm disorders reach their reproductive years and require medication. Information on the effect of antiarrhythmic agents on the human fetus as well as the possible changes in therapeutic response during the altered state of pregnancy is limited. In principle, the approach to the treatment of arrhythmias in pregnant patients is similar to that in nonpregnant patients. Special consideration, however, must be given with regard to drug selection and dosage in order to avoid adverse effects on the mother and fetus.

Norfloxacin disposition after sequentially increasing oral doses

Single doses of norfloxacin (200, 400, 800, 1,200, and 1,600 mg) or placebo were administered orally at weekly intervals to 14 healthy male volunteers in a double-blind study. Norfloxacin was measured in serum and urine by high-pressure liquid chromatography with UV detection. The concentrations of this drug in serum peaked 1 to 2 h after each dose; the mean peak values for increasing doses were 0.75, 1.58, 2.41, 3.15, and 3.87 micrograms/ml. Mean area under the serum concentration-time curves for the first 12 h after each dose were 3.56, 6.26, 11.4, 16.1, and 19.7 micrograms . h/ml, respectively. The elimination half-life of norfloxacin was about 7 h and was similar for all doses. The concentrations of the drug in urine also peaked 1 to 2 h after dosage; mean peak values for increasing doses were 200, 478, 697, 992, and 1,045 micrograms/ml. Renal clearances approximated 285 ml/min. About 30% of each dose was excreted into urine as unmetabolized norfloxacin. Crystals of the drug were occasionally observed during microscopic examination of freshly voided urine collected after the 1,200- and 1,600-mg doses. Crystalluria was not encountered at lower doses.

Cimetidine does not alter morphine disposition in man

1 The pharmacokinetic parameters of morphine were determined in a crossover fashion following 4 days pretreatment with cimetidine, 300 mg every 6 h, or placebo. 2 Cimetidine had no apparent effect on the mean morphine plasma clearance, volume of distribution, AUC or half-life (P greater than 0.05; power greater than 0.80). 3 Cimetidine had no apparent effect on the magnitude or duration of morphine induced miosis. 4 The absence of a demonstrable effect on the pharmacokinetics of a drug with a high extraction ratio such as morphine suggests that cimetidine did not significantly reduce hepatic blood flow in ambulant normal volunteers.