Treatment of hypertension in the elderly. III. Response of isolated systolic hypertension to various doses of hydrochlorothiazide: results of a Department of Veterans Affairs cooperative study. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents

In a double-blind randomized study, we evaluated the effects of 25 mg vs 50 mg of hydrochlorothiazide in 51 elderly patients (aged 68.9 +/- 7.0 years) with isolated systolic hypertension (blood pressure, 160 to 239 mm Hg systolic and less than 90 mm Hg diastolic). Dose levels could be increased to twice daily to control blood pressure. The reductions in blood pressure (25.4/6.8 mm Hg and 28.9/7.4 mm Hg) and proportion of patients in whom blood pressure was controlled (78% and 89%) were similar in the lower- and higher-dose groups during the titration phase. However, serum potassium level was reduced more in the higher-dosage (0.57 mmol/L) than the lower-dosage (0.17 mmol/L) group. There were no significant changes in blood pressure during a 24-week maintenance phase. No patient required withdrawal from the study because of adverse effects, and cognitive-behavioral function was well preserved. We conclude that hydrochlorothiazide is effective and well tolerated in older patients with isolated systolic hypertension, many of whom may be effectively treated with 25 mg of hydrochlorothiazide once daily.

Abnormal left ventricular diastolic filling in eccentric left ventricular hypertrophy of obesity

Left ventricular (LV) diastolic filling pattern of obese subjects with eccentric LV hypertrophy was studied. Findings were compared with those of normal control subjects and hypertensive patients with concentric LV hypertrophy. M-mode, 2-dimensional and Doppler echocardiograms were recorded in 11 obese (body mass index greater than 30 kg/m2) normotensive patients with eccentric LV hypertrophy, 10 normal control subjects, and 18 nonobese, hypertensive patients with concentric LV hypertrophy whose antihypertensive medications were discontinued 2 weeks before study. LV hypertrophy was defined as LV mass/height greater than 143 g/m. Hypertrophy in the obese patients was eccentric: Their LV internal dimension (61 +/- 3 mm) was greater than that of hypertensive patients (55 +/- 5 mm, p less than 0.001) and normal control subjects (55 +/- 2 mm, p less than 0.01); their septal (10.7 +/- 0.7 mm) and posterior (10.9 +/- 0.6 mm) wall thicknesses were smaller than those of the hypertensive patients (12.2 +/- 1.7 mm, p less than 0.05 and 11.7 +/- 1.2 mm, respectively, difference not significant). Pulsed-wave Doppler echocardiographic filling indexes were used to evaluate LV diastolic filling. Obese patients had a higher peak velocity of atrial filling (69 +/- 14 vs 54 +/- 15 cm/s, p less than 0.05), lower early/atrial filling velocity ratio (1.0 +/- 0.26 vs 1.32 +/- 0.21, p less than 0.05), prolonged deceleration half-time (108 +/- 9 vs 86 +/- 15 ms, p less than 0.01) and lower peak filling rate corrected to stroke volume (4.08 +/- 0.68 vs 4.96 +/- 0.88 stroke volume/s, p less than 0.05) than normal control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Classic therapeutic trials in hypertension. Were patients vulnerable to unsuppressed peak morning blood pressure?

A metaanalysis of the major clinical trials on the benefits of antihypertensive therapy revealed that there is an overall reduction of coronary events by treatment, but that it is only about one-half of the reduction predicted. The reduction in stroke achieved the predicted number. This "failure" has been attributed to study design, patient age at entry, preexisting disease, high-lipid diets, drug-associated cardiac dysrhythmias, and the "J-curve" effect. It is also possible that the drugs used in these trials did not suppress the morning acceleration of blood pressure during which most coronary and cerebrovascular events occur. Ambulatory blood pressure monitoring studies suggest that antihypertensive drugs reduce overall blood pressure throughout the 24-h period, but do not change the circadian curve. The beneficial effect of antihypertensive therapy probably rests with the magnitude of blood pressure reduction. It is unlikely that lack of suppression of morning acceleration alone accounted for the failure of "older" drugs to prevent as much cardiac mortality as expected.

Renal biopsy in patients 65 years of age or older. An analysis of the results of 334 biopsies

We studied the clinical and pathological data for 334 patients age 65 or more who underwent renal biopsy for acute renal failure (ARF, n = 55), subacute renal failure (SRF, n = 72), chronic renal failure (CRF, n = 57), proteinuria (n = 137), and hematuria (n = 13). Tissue diagnoses were glomerulopathy (n = 252, 75.4%), acute tubular lesions (n = 18), interstitial nephritis (n = 23), vascular diseases (n = 36, including 14 with cholesterol emboli), and five miscellaneous diagnoses. Of the 55 patients with ARF, 23 had a glomerular lesion, 15 had acute tubular necrosis, and 8 had acute interstitial nephritis. Of 72 patients with SRF, 49 had a glomerulopathy, 12 had a vascular disorder, and six had acute interstitial nephritis. Hence, patients with ARF or SRF exhibited a high potential for reversible lesions. Only 11.3% of patients with CRF had potentially reversible causes. The most common causes of proteinuria were membranous glomerulopathy (34.3%), minimal change disease (14.6%), focal segmental sclerosis (11.7%), and amyloidosis (8.8%). Of the 25 patients with advanced nephrosclerosis, 24 had renal failure, 20 were hypertensive, and 13 had cholesterol emboli. Of 33 patients with diabetes mellitus, 66.7% were found to have lesions not related to diabetes. We conclude that renal biopsy is most useful in older patients with ARF or SRF because of potentially reversible renal disease. Old age alone is not a contraindication to performing a renal biopsy.

Right ventricular diastolic function in systemic hypertension

Right (RV) and left ventricular (LV) diastolic function was evaluated in 50 patients with mild, uncomplicated essential hypertension using pulsed-wave Doppler echocardiography. Patients with pulmonary, valvular or coronary artery disease were excluded and antihypertensive drugs were discontinued for the 2 weeks preceding the study. Ten normotensive patients without heart disease acted as control subjects. In the hypertensive patients, RV peak velocity of atrial filling was higher (42 +/- 10 vs 31 +/- 7 cm/s, p less than 0.01) and deceleration half-time was prolonged (96 +/- 20 vs 83 +/- 10 ms, difference not significant); ratio of early/atrial filling velocity (1.1 +/- 0.3 vs 1.7 +/- 0.4, p less than 0.001) and peak filling rate corrected to stroke volume (3.6 +/- 0.7 vs 5.3 +/- 0.9 SV/s, p less than 0.001) were lower. LV filling parameters showed similar changes. RV filling parameters did not correlate with age, LV mass or septal thickness but correlated weakly with LV radius/thickness ratio. There was good correlation between RV and the following corresponding LV filling parameters: peak filling rate, r = 0.68, p less than 0.001; ratio of early/atrial filling, r = 0.88, p less than 0.0001; and deceleration half-time, r = 0.62, p less than 0.001. Data indicate that RV diastolic function is abnormal in essential hypertension and these abnormalities are closely related to those of LV diastolic function.

Treatment of hypertension in the elderly: I. Blood pressure and clinical changes. Results of a Department of Veterans Affairs Cooperative Study

We compared the efficacy and adverse effects of antihypertensive drug regimens in 690 men past age 60 with diastolic blood pressure 90-114 mm Hg and systolic blood pressure less than 240 mm Hg. They received either a low (25-50 mg) or high (50-100 mg) dose of hydrochlorothiazide daily. Of 644 patients who completed the hydrochlorothiazide titration, 375 (58.2%) were responders (diastolic blood pressure less than 90 and less than or equal to 5 mm Hg below baseline) and 92.8% of these completed a 6-month maintenance period. Blood pressure was reduced from 157.6/98.5 mm Hg by 18.3/9.5 mm Hg with low dose hydrochlorothiazide and by 20.4/9.6 mm Hg with high dose hydrochlorothiazide; more patients achieved goal blood pressure with the high dose. Whites and blacks responded equally. Serum potassium less than 3.5 mmol/l occurred in 104 of 321 (32.3%) of the high dose versus 62 of 333 (18.6%) of the low dose hydrochlorothiazide patients. The 269 nonresponders to hydrochlorothiazide were randomly assigned in a double-blind study to receive hydralazine, methyldopa, metoprolol, or reserpine in addition to hydrochlorothiazide; 79.2% responded to the addition of the second drug and 87.3% of these completed a 6-month maintenance phase. Overall, there were no significant efficacy differences among the step 2 regimens. We conclude that the lower dose of hydrochlorothiazide was nearly as effective as the higher dose, and the addition of a second drug was effective and generally well tolerated in elderly patients.

Treatment of hypertension in the elderly: II. Cognitive and behavioral function. Results of a Department of Veterans Affairs Cooperative Study

This study was designed to determine whether blood pressure reduction, per se, causes adverse effects on cognitive and behavioral function in elderly hypertensive patients. Men with mild-to-moderate diastolic hypertension who had passed their 60th birthday were entered into the trial. After a placebo washout period, they were assigned in a randomized, double-blind manner to one of two groups receiving hydrochlorothiazide (either 25 mg once or twice daily or 50 mg once or twice daily). Responders entered a 1-year maintenance period. Nonresponders were randomly assigned to double-blind treatment with hydralazine, methyldopa, metoprolol, or reserpine added to the diuretic therapy. During the placebo and treatment periods, patients underwent a battery of psychometric tests designed to assess cognitive function, motor skills, memory, and affect. A separate questionnaire assessed the patient's ability to perform activities of daily living. A subset of patients blindly being treated with placebo received the same battery of tests as a control for practice effect. The results showed that there was similar improvement on the psychometric tests between those patients whose blood pressure was successfully reduced and the placebo-treated control group. Therefore, the practice effect did not obscure a true deterioration in function. There were no substantive differences between the lower and higher doses of diuretic or among the four drugs added to the diuretic, although there were qualitative differences in side effects. We conclude that blood pressure reduction, per se, does not adversely affect cognitive and behavioral function in elderly hypertensive patients and that antihypertensive treatment is safe and effective in these patients.

Newer principles of patient profiling for antihypertensive therapy

The mosaic of essential hypertension seems to be gaining new tiles at an accelerating rate. Of the many pathophysiological factors and markers for the factors that can be considered as possible elements of a profiling algorithm, there are relatively few with solid data to support their use. Use of plasma renin activity for prospective profiling does not appear to be valid for individual patients. It remains useful for diagnosis of renal artery stenosis and primary aldosteronism. The black race does have some well-documented pathophysiological differences from the white race regarding hypertension, and there are some useful data bits for selecting specific therapy. The elderly, obese patients, and young patients with hyperdynamic circulation appear to have enough group characteristics to enable selection of drugs more targeted to their needs. Anxious patients who often display symptoms that mimic pheochromocytoma symptoms comprise a unique group. One of the largest groups is patients with hypertension plus one or more concomitant diseases. Finally, drug selection decisions must also consider the effect of drugs on serum lipoproteins, left ventricular hypertrophy and vascular compliance, sexual function and other quality of life issues, and cost.

The anion gap of patients receiving bicarbonate maintenance hemodialysis

To compare the effect of maintenance bicarbonate hemodialysis on the serum anion gap (AG) and the serum HCO3, the authors retrospectively evaluated the data of 28 patients using the first-of-the-month blood chemistries. Data were available for at least 9 of the previous 12 months in each case. For the entire group, the average AG was 15.8 +/- 0.1 mEq/L and the HCO3 21.7 +/- 0.2 mEq/L. Comparing these values with the data compiled recently by three different groups of investigators in undialyzed patients with severe chronic renal failure indicates that the AG of the dialyzed patients was similar to that of untreated patients, but the HCO3 levels of dialyzed patients averaged 2 to 3 mEq/L higher. Separate prospective evaluation of the acute effect of two consecutive bicarbonate dialyses in 31 patients revealed that the average acute (immediate postdialysis) decrease (from predialysis values) in AG was only about 40% of that of the increase in HCO3. The authors conclude that bicarbonate dialysis is more effective in improving serum HCO3 than AG.

Influence of beta 2 agonism and beta 1 and beta 2 antagonism on adverse effects and plasma lipoproteins: results of a multicenter comparison of dilevalol and metoprolol

Dilevalol combines vasodilation due to selective beta 2 agonism and nonselective beta antagonism. We studied 311 patients randomized to dilevalol and 138 to metoprolol in a multicenter trial. After a 4-week placebo washout, dilevalol was titrated from 200 to 1,600 mg once daily and metoprolol from 100 to 400 mg to a goal supine diastolic blood pressure less than 90 and greater than or equal to 10 mm Hg decrease from baseline. Responders were followed for 1 year. The average age of patients was 51 years; 72% were men and 54% were white. Both drugs reduced blood pressure effectively to a similar level. Fewer patients discontinued dilevalol than did those taking metoprolol (9 vs 16%; p less than 0.03). More metoprolol-treated patients withdrew because of depression (6 vs less than 1%; p = 0.03) and impotence (5 vs less than 1%; p = 0.03). Lipoprotein levels before and after treatment were measured in 99 patients treated for 53.5 weeks with dilevalol (mean dose 438 mg). Dilevalol increased high-density lipoprotein (HDL) cholesterol by 2.5 mg/dl to 47.2 (p = 0.05), reduced low-density lipoprotein (LDL) cholesterol by 2.5 mg/dl, increased HDL/LDL by 0.03, and decreased total cholesterol/HDL cholesterol by 0.18. Triglycerides increased by 21 mg/dl (p = 0.06). In patients with an initial HDL cholesterol less than 35 mg/dl, dilevalol increased it by 9 mg/dl. In patients treated with metoprolol, the only significant change (p = 0.02) was a 41.9-mg/dl increase in triglyceride levels.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of administration of lithium salts and magnesium sulfate on the serum anion gap

Whether or not an increased serum level of an unmeasured cation will reduce the anion gap (AG) depends on concomitant changes (or lack thereof) in serum unmeasured anions. In the present retrospective study, we sought to determine the effect of lithium carbonate or citrate and magnesium sulfate on the AG. Two groups of psychiatric patients whose average serum lithium levels were 0.6 and 1.0 mEq/L were studied. The AG in each group (10.2 +/- 0.3 [SE] and 9.0 +/- 0.4 mEq/L, respectively) was significantly (P less than 0.05) lower than that of a control group (11.1 +/- 0.3 mEq/L). Separately, we collected 87 pairs of AG and serum magnesium data of patients with toxemia of pregnancy. These included those of 15 patients evaluated both before and during magnesium sulfate infusion. Despite an average serum magnesium level of 4.1 +/- 0.2 mEq/L, the AG of the latter subjects tended to increase slightly from 10.8 +/- 0.5 to 11.7 +/- 0.7 mEq/L during magnesium infusion, instead of decreasing. The other data (72 determinations in the 55 patients without preinfusion values) revealed a mean AG of 11.0 +/- 0.3 mEq/L, coexisting with an elevated serum magnesium of 4.1 +/- 0.1 mEq/L. None of the above-mentioned three mean AG values differed significantly from that of the control group. We conclude that hypermagnesemia resulting from the administration of magnesium sulfate does not reduce the AG, probably because of a concomitant and proportional increase in serum sulfate. The present data reemphasize the need to assess the anion gap as the result of concomitant changes in both unmeasured anions and cations.

Metabolic alkalosis induced by regional citrate hemodialysis

Two patients are described in whom regional citrate dialysis (RCD) and induced metabolic alkalosis with marked increases in serum HCO3, which were sustained during the period of repeated treatments. As currently employed, RCD of necessity delivers large amounts of potential bicarbonate (several hundred mEq) to the patient and may cause severe metabolic alkalosis. Studies should be carried out to determine an effective method to avoid this complication whenever repeated RCD is necessary or is used in patients with pre-existing alkalosis.

Cigarette smoking interferes with treatment of hypertension

We retrospectively analyzed two studies to determine whether smoking affected the treatment of hypertension. In a study of the effects of propranolol hydrochloride (a hepatically metabolized beta-blocker) vs hydrochlorothiazide, 108 smokers and 232 nonsmokers were randomized to the propranolol treatment group. The propranolol-treated smokers tended to be younger, taller, thinner, and wre more likely to be black. This group also had an initial blood pressure reduction (+/- SD) of -7.9 +/- 12.9/-8.7 +/- 8.4 mm Hg compared with -10.7 +/- 13.0/-10.9 +/- 7.1 mm Hg for the nonsmokers. Blood pressure increased less during the one-year maintenance period for the nonsmokers. However, when analyzed by race, this effect was seen in blacks, but not in whites. Diastolic blood pressure tended to be reduced more in nonsmokers (vs smokers) receiving hydrochlorothiazide (-12.1 +/- 6.7 vs -10.7 +/- 6.7 mm Hg, respectively). The second study compared the effects of nadolol (a renally excreted beta-blocker) with bendroflumethiazide. There were no significant effects on blood pressure for either of these drugs. In both studies, there was a greater tendency for smokers to be terminated from the study irrespective of drug group. We conclude that cigarette smoking does interfere with the treatment of hypertension in general, and especially with reduction of blood pressure by propranolol in black patients.

Volume (weight) loss and blood pressure response following thiazide diuretics

Correlations were made between weight change (as an index of volume loss) and blood pressure (BP) reduction before and after hydrochlorothiazide treatment. A total of 343 patients with mild to moderate hypertension (95-114 mm Hg) received hydrochlorothiazide alone. The diuretic was titrated from 50 to 100 to 200 mg daily as needed until the diastolic BP fell below 90 mm Hg (goal BP) or side effects supervened. Of the 305 patients who completed the 10-week titration period, 65% attained goal BP. The effective dose of hydrochlorothiazide in 52% of these responders was 50 mg/day, and this was associated with weight loss averaging 1.58 kg. An additional 29% achieved goal BP with a similar degree of weight loss, but they required double the dose, or 100 mg/day. The remaining 19% of responders required significantly greater weight reductions averaging 3.14 kg to achieve goal BP, which necessitated hydrochlorothiazide, 200 mg/day. More blacks than whites attained goal BP despite similar degrees of weight loss in the two races. Plasma renin activity was initially higher in whites than in blacks and rose significantly more in blacks and whites requiring the greatest volume losses and the highest dose of hydrochlorothiazide to attain goal BP. Nonresponders had less weight loss than responders. Thus, diuretic dose requirements vary in different patients and are related either to different volume losses in response to a given dose or to different degrees of BP reduction in response to the same volume loss.

Geriatric hypertension: the growing use of calcium-channel blockers

The recognition of essential hypertension as a heterogeneous entity mandates that therapy be individualized according to the subset of hypertension that characterizes each patient. Choosing the most appropriate therapeutic regimen in elderly hypertensives is complicated by a greater susceptibility to side effects from medications, and by concomitant diseases. Calcium-channel blockers address the pathophysiologic mechanisms of generic hypertension, thus providing clinicians with more specific pharmacologic tools for treating elderly hypertensives. In addition, these agents will avoid many of the side effects of other antihypertensive agents and can ameliorate certain concomitant diseases.

Use of the anion gap in clinical medicine

The anion gap (AG) in the serum equals the concentrations of Na-(Cl + HCO3). It is becoming increasingly useful in the interpretation of acid-base disorders and in the diagnosis of other conditions. In an acidemic patient, an elevated AG usually indicates the presence of an organic acidosis, rhabdomyolysis, nonketotic hyperglycemic coma, uremia, or certain intoxications. An increased AG with alkalemia suggests severe alkalosis with hemoconcentration or use of anionic antibiotics (eg, carbenicillin) or salts of organic acids (eg, citrate). An elevated AG with a normal serum pH could be an artifact caused by prolonged exposure of the serum sample to air before processing. A decreased AG with a normal serum pH may indicate hypoalbuminemia, cationic paraproteinemia, halide poisoning, or lithium intoxication. The delta AG/delta HCO3 ratio and the urinary AG may also be quite useful in analyzing complex acid-base disorders.

Special uses for captopril

Plasma renin activity (PRA) is markedly increased by captopril. There is not enough separation between the changes in PRA of patients with renal artery stenosis (RAS) to separate them reliably from those with essential hypertension. A minimal response may suggest primary aldosteronism. Captopril does increase the ratio of PRA in the venous blood from a kidney with RAS to that of the contralateral kidney. Captopril, 25 to 50 mg orally, given before renal vein PRA sampling will increase the sensitivity and specificity of the test. Treatment with current antihypertensive drugs need not be discontinued. Scleroderma renal crisis (SRC) used to be uniformly lethal within a few months. Modern, aggressive antihypertensive therapy has made survival of 2 or more years common. Not all patients respond, and some progress to renal failure despite good BP control. Captopril has been used with success in some patients with idiopathic edema. In conclusion, captopril markedly enhances the accuracy of renal vein renin assay for the diagnosis of RAS and is of major value in the treatment of SRC.

Evaluation of antihypertensive efficacy of lisinopril compared to metoprolol in moderate to severe hypertension

A double-blind controlled, randomized, parallel, multicenter 12-week study was conducted to compare the antihypertensive efficacy of lisinopril with that of metoprolol in treatment of moderate to severe hypertension. Initially, 118 patients were recruited on lisinopril and 61 on metoprolol; and for the purpose of efficacy analysis at week 8, 115 patients on lisinopril and 60 on metoprolol were included. The doses of lisinopril or metoprolol were 40-80 mg/day and 100-200 mg/day, respectively. At week 4, the pretreatment diastolic blood pressure of 111 mm Hg was decreased to 97 mm Hg (p less than 0.01) with lisinopril: metoprolol decreased the diastolic blood pressure from 110 to 99 mm Hg (p less than 0.01). Similar decreases were noted at week 8; however, the drop in blood pressure with lisinopril was not significantly different from that with metoprolol. Systolic blood pressure also demonstrated a decrease of about 18 mm Hg with lisinopril and 12 mm Hg with metoprolol (p less than 0.01). This larger decrease in systolic blood pressure with lisinopril was statistically significant at week 4 (p less than 0.05). These decreases in systolic blood pressures were maintained at week 8, again with statistical significance (p less than 0.01). Of the 118 lisinopril-treated patients, four were discontinued from lisinopril therapy because of headache, dizziness, rash, flushing, or lymphadenopathy. Four patients out of 61 (9.8%) were discontinued from metoprolol therapy because of fatigue, somnolence, asthenia, weight gain, flatulence, tremor, or bronchospasm. In conclusion, lisinopril 40-80 mg once daily is as effective as metoprolol 100-200 mg once daily in reducing diastolic blood pressure in patients with moderate to severe hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Pseudohypertension: a diagnostic dilemma

Pseudohypertension is a condition in which the indirect measurement of intra-arterial pressure using a sphygmomanometer (cuff pressure) is artifactually high in comparison with directly measured intra-arterial pressure. If unrecognized, pseudohypertension may result in unwarranted and sometimes dangerous treatment. Pseudohypertension results from medial sclerosis and/or calcification of arteries, which markedly decrease their collapsibility. Both the systolic and diastolic pressures are affected. The literature concerning pseudohypertension is quite limited; indeed, the very frequency of the condition is unknown. Very high blood pressure in the absence of significant target organ impairment is an important clue to this subtype of hypertension and should lead to simple diagnostic techniques, such as Osler's maneuver (an attempt to palpate a pulseless radial artery) and radiographs of the soft tissues of the arms. The definitive diagnosis is made by comparing the intra-arterial pressure with the indirectly determined blood pressure.

A multicenter, randomized, double-blind dose-response evaluation of step-2 guanfacine versus placebo in mild to moderate hypertension

Guanfacine, an alpha-adrenoceptor agonist, may exhibit distinct dose-related curves for efficacy and adverse effects in the step-2 therapy of essential hypertension. To determine the lowest clinically effective safe dose, 462 newly or previously diagnosed subjects were admitted to a 5-week prerandomization phase at 8 centers. Patients were weaned from any current antihypertensive drugs and placed on 25-mg chlorthalidone, daily, in the morning. At the end of the 5-week weaning period, 362 patients with seated diastolic blood pressures (BPs) between 95 and 114 mm Hg qualified for the 12-week postrandomization phase. Subjects were randomized to receive either an indistinguishable placebo or 0.5, 1, 2 or 3 mg of guanfacine. Chlorthalidone was changed to bedtime administration and taken with the study medications. Guanfacine was started at the lowest dose in all subjects and increased (if scheduled, according to the randomization code) to the next higher dose at biweekly intervals. Of the 362 randomized patients, 278 completed the study. The 1-mg guanfacine dosage produced a 14/13 mm Hg decrease in BP (p less than 0.0125 compared with placebo). Doses of guanfacine at 2 and 3 mg/day were not more effective than the 1 mg/day dose; 0.5 mg/day was not better than placebo. There was an increase in the frequency of side effects possibly or probably associated with 2 and 3 mg/day guanfacine. Only 3.2% of the patients in the 1 mg/day group dropped out of the study because of side effects. We conclude that when added to a diuretic, 1 mg/day guanfacine at bedtime is the lowest safe and therapeutically effective dose.

Adverse effects of antihypertensive treatment

Elevated blood pressure can be lowered safely in the vast majority of patients by selecting the single drug most likely to be efficacious in that patient. Skillful management with full knowledge of drug pharmacology should provide the patient with the maximum opportunity to benefit from normalization of blood pressure while at the same time having little or no impact on quality of life.

Comparative effects of diltiazem and hydrochlorothiazide in blacks with systemic hypertension

The blood pressure-lowering effects of a calcium-entry blocker, diltiazem (240 or 360 mg/day), and a thiazide diuretic, hydrochlorothiazide (50 or 100 mg/day), were studied in 20 black hypertensive patients. Supine blood pressure decreases of -34/-18 mm Hg for diltiazem and -29/-21 mm Hg for hydrochlorothiazide were noted after 14 weeks of therapy. Differences between drugs were not significant. Blood pressures were normalized in all 4 of the monotherapy nonresponders when the 2 drugs were combined. Significant adverse effects were not noted. These data suggest that diltiazem is an effective antihypertensive agent in black patients. As monotherapy, its blood pressure-lowering effect is equivalent to hydrochlorothiazide.

Black/white differences in response to antihypertensive therapy

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Monotherapy with labetalol compared with propranolol. Differential effects by race

The antihypertensive effect of oral labetalol and propranolol were evaluated in 65 black and 75 white patients with mild to moderate hypertension (standing diastolic blood pressure (StDBP) of 90-115 mmHg) in a double-blind multicenter clinical trial. Following a 4-week placebo phase, labetalol (n = 70) or propranolol (n = 70) was randomly assigned. During a 5-week titration phase, labetalol could be increased from 100 mg BID to 600 mg BID to achieve a StDBP of less than 90 mmHg and a decrement of greater than or equal to 10 mmHg. Propranolol could be titrated from 40 to 240 mg BID. A 3-month maintenance phase was followed by an optional 8-month maintenance phase. Hydrochlorothiazide (HCTZ) could be added at any time during the maintenance phase. Supine and standing blood pressures were measured at each visit. Statistical analysis revealed significant (ANOVA, p less than 0.05) treatment by race effects. Therefore, the treatment groups were stratified retrospectively by race. This study demonstrated that labetalol is equally effective in white and black patients, whereas, propranolol is significantly (p less than 0.05) more effective in white than in black patients. Moreover, labetalol is significantly more effective than propranolol in lowering the standing systolic/diastolic blood pressure of black patients (p less than 0.02/p less than 0.001). These blood-pressure effects were accompanied by a significantly greater (p less than 0.04) reduction in heart rate with propranolol. Furthermore, significantly more (p less than 0.05) black patients treated with propranolol compared to those treated with labetalol required the addition of a diuretic for control of their blood pressure.

Monotherapy of hypertension with angiotensin-converting enzyme inhibitors

Angiotensin-converting enzyme (ACE) inhibitors are clearly effective treatment for all stages of hypertension. Since the introduction of captopril in 1981, numerous ACE inhibitors have been synthesized and are under investigation. Their exact antihypertensive mechanism of action remains unclear. Part of their effect may be mediated by vasodilator prostaglandins. Early studies with as much as 1,000 mg a day captopril demonstrated the agent's ability to reduce blood pressure, but only 10 percent of the severely hypertensive patients were controlled with monotherapy. Subsequent studies have demonstrated that patients with mild to moderate hypertension can be controlled with ACE inhibitor alone, although there is a tendency for the very low doses to lose their effect with time. Black patients are less readily controlled with monotherapy. Captopril has now been demonstrated to be effective in the hypertension of scleroderma and has reversed scleroderma renal crisis. ACE inhibitors are also effective for the treatment of severe congestive heart failure.

Angiotensin converting enzyme inhibitors in the treatment of hypertension

Converting enzyme inhibitors appear to be a safe and effective class of drug for treating the entire spectrum of hypertension, from very mild to severe. For the vast majority of patients who do not experience adverse side effects, these drugs appear to be remarkably well tolerated and are without the adverse metabolic and depressive effects associated with other antihypertensive drugs. Many patients report an enhanced feeling of well-being and may even experience euphoria. Whenever possible, CEIs should be used in the lowest possible effective dose in order to achieve maximum therapeutic benefit with a minimum or complete absence of adverse effects.

Insights into intrarenal sites and mechanisms of action of diuretic agents

Effective diuresis requires both sufficient glomerular filtrate and adequate delivery of the diuretic drug to the lumen of the renal tubule. Diuretics will not "force open" the kidney. Diuretics that work primarily in the proximal tubule include osmotic diuretics (e.g., mannitol), diuretics that interfere with the adenyl cyclase system (e.g., xanthines), and those which inhibit carbonic anhydrase (e.g., acetazolamide). Some thiazide and thiazide-like diuretics have a secondary site of action in the proximal tubule based on either carbonic anhydrase inhibition or other mechanisms, such as inhibition of sodium phosphate reabsorption. The diuretics that work primarily in the medullary diluting segment of the loop of Henle, furosemide and ethacrynic acid, block the active reabsorption of chloride and interfere with the tubular reabsorption of free water. The exact mechanism remains unknown. These diuretics tend to have a "high ceiling," to be potent and rapidly acting, and to have a short duration of effect. They are excellent for the treatment of severe fluid overload or pulmonary edema but are not ideal for the treatment of uncomplicated hypertension. Furosemide is a sulfonamide derivative; ethacrynic acid can be used in patients who are allergic to sulfa drugs. Diuretics that work primarily in the cortical diluting segment include the thiazides and thiazide-like drugs. They inhibit sodium transport by an undetermined mechanism. Most of them seem to reach a dose-response plateau beyond which little additional effect is gained by increasing the dose. Most of them appear to lose efficacy as the glomerular filtration rate decreases, except for metolazone and indapamide. The thiazides are most commonly used to treat hypertension. Diuretics that work primarily in the distal tubule and collecting tubule include the aldosterone inhibitor spironolactone and two drugs that impair tubular reabsorption of sodium by direct action, triamterene and amiloride. These drugs are primarily used for their potassium-sparing effect.

Comparison of propranolol or hydrochlorothiazide alone for treatment of hypertension. III. Evaluation of the renin-angiotensin system

In this study, the relation between renin activity and therapeutic response to hydrochlorothiazide or propranolol was studied. Patients with a diastolic blood pressure of 95 to 114 mm Hg were treated with propranolol (40 to 320 mg twice daily) or hydrochlorothiazide (25 to 100 mg twice daily). The initial renin profiles were: low, 56 percent (n = 300); normal, 33 percent (n = 174); high, 11 percent (n = 60). A greater incidence of low and fewer high renin profiles (p less than 0.001) were observed in blacks. After furosemide administration (40 mg intravenously), 55 percent of patients (n = 291) had a low renin response and 45 percent (n = 240) had a normal renin response. No correlation between renin profile and renin response was observed, although low renin response and low renin profile occurred more frequently in older patients. Hydrochlorothiazide administration resulted in a greater decrement in diastolic blood pressure (p less than 0.05) in the total group. Irrespective of renin activity, both hydrochlorothiazide and propranolol reduced diastolic blood pressure. When renin profile was considered, no significant variation in response to hydrochlorothiazide therapy was observed, and there was a greater reduction in diastolic blood pressure in the patients with a high renin profile receiving propranolol. In comparing therapeutic response, patients with a low renin profile had a better response to hydrochlorothiazide, and propranolol was more effective in patients with a high renin profile. The anticipated effect of therapy on plasma renin activity was observed. Although these results are consistent with a volume-vasoconstrictor analysis of hypertension, the results of therapy could not have been prejudged from renin profile or responsivity. The slight differences observed do not warrant the expense of renin determinations when a simple determination of therapeutic response is sufficient.

Slow-release oxprenolol compared with oxprenolol in hypertensive patients: a multicenter clinical trial

Oxprenolol (OX) is a nonselective, beta-adrenergic blocking agent with intrinsic sympathomimetic activity. We studied 178 patients in five centers to determine whether a polymer-matrix-based, slow-release preparation of oxprenolol (SR-OX) given once daily was as effective as the standard preparation given twice daily for the treatment of patients with mild to moderate hypertension. After a placebo washout phase, patients were treated with OX until blood pressure was controlled. They were then randomized in a double-blind fashion to continue the same dose, given as either OX bid or SR-OX qd with a placebo as the second dose. All patients took hydrochlorothiazide 50-100 mg/d throughout the study. Blood pressure was reduced 23/15 mm Hg (p less than 0.001) and pulse 8 beats/min in the SR-OX group (n = 67) and 24/17 mm Hg (p less than 0.001) and 8 beats/min in the OX group (n = 72) by titrating standard OX. After randomization to SR-OX or OX, there were no further changes over six weeks. Home-determined blood pressures showed no loss of control in the evening. There were no unexpected adverse effects. We conclude that SR-OX given once daily is as effective as OX given twice daily for the treatment of hypertension.

Laxative abuse syndrome

Laxative abuse syndrome (LAS) is a type of Münchausen syndrome characterized by surreptitious abuse of purgatives. Clinical findings are often perplexing and may mimic inflammatory bowel disease or malabsorption syndromes. Patients frequently complain of diarrhea alternating with constipation and may have nausea, vomiting and weight loss. Psychiatric disturbances are common and may include anorexia nervosa. Melanosis coli and cathartic colon, acid-base disturbances (usually metabolic alkalosis), sodium, potassium and water depletion, hyperuricemia, hyperaldosteronism and other electrolyte changes are possible complications. Diagnosis may be extremely difficult and may require special chemical analysis of urine and feces and search of the patient's possessions. Treatment is frustrating because the patient is rarely willing to admit to laxative abuse let alone cooperate in attempting to stop it. Physicians must be aware of the LAS in order to avoid harming the patient with extensive, expensive and often invasive (including laparotomy) procedures.

Dose response to chlorthalidone in patients with mild hypertension. Efficacy of a lower dose

A multicenter study of chlorthalidone was performed to determine the relative antihypertensive efficacy and side effects of doses lower than those usually recommended for therapy. After a 4-wk placebo control period 100 patients with mild hypertension were randomly assigned doubleblind to 12.5-, 25-, 50-, or 75-mg regimens of chlorthalidone or to placebo for 12 wk. The groups of patients taking 25, 50, and 75 mg had declines in blood pressure which were not significantly different from each other. Serum potassium decreased in the 50- and 75-mg groups but not significantly in the 25-mg group. We conclude that chlorthalidone, 25 mg daily, was at least as effective for hypertension as 50 and 75 mg with less perturbation of potassium. Use of smaller initial diuretic doses may provide equal efficacy with fewer side effects for many patients.

Exacerbation of hepatic encephalopathy by chronic renal failure: response to maintenance hemodialysis

The consequences of chronic renal insufficiency relevant to hepatic failure are not well appreciated. We describe a patient with chronic cirrhosis and marked porto-systemic shunting who, after the onset of chronic renal failure, developed intractable encephalopathy which improved markedly during an eight month period of maintenance hemodialysis.

Antihypertensive effects of oxprenolol and propranolol

The antihypertensive effects of the beta blockers oxprenolol and propranolol were compared in a randomized double-blind study of patients with standing diastolic pressures (SDP) exceeding 99 mm Hg when receiving hydrochlorothiazide alone. After 3 wk of hydrochlorthiazide with placebo, the latter was replaced with oxprenolol (n= 12) or propranolol (n = 14), 20 mg three times daily. Beta blocker was increased subsequently to 40 and 80 mg three times daily if SDP exceeded 89 mm Hg. Nine oxprenolol and 7 propranolol subjects were hospitalized for 24-hr monitoring. With oxprenolol, standing pressure declined from 135 +/- 2 (SE)/104 +/- 1 MM Hg to 128 +/- 3/90 +/- 2. SDP declined to under 91 mm Hg in 7 of 12 subjects, and to from 91 to 95 in 3 subjects. With propranolol, findings were 138 +/- 3/106 +/- 2 to 123 +/- 3/89 +/- 3; in 7 of 12 to less than 91 mm Hg and from 91 to 95 in 4 subjects. Decrements in supine and SDP were slightly (4 mm Hg) greater for propranolol than for oxprenolol. Both drugs gave similar 24-hr blood pressure control. We conclude that oxprenolol and propranolol used to supplement hydrochlorothiazide provide comparable reductions in blood pressure and smooth control over a 24-hr period in most patients with hypertension.

Antihypertensive effectiveness of oxprenolol administered twice daily

Oxprenolol, a beta-blocker, is an effective antihypertensive when administered 3 or 4 times daily. We evaluated the antihypertensive effect of oxprenololgiven twice daily (bid). The subjects were 15 ambulatory men whose standing diastolic blood pressure (BP) was at least 100 mm Hg after 3 wk of treatment with hydrochlorothiazide and oxprenolol placebo. Oxprenolol 40 mg twice daily was then substituted for the placebo. On subsequent weekly vists oxprenolol was titrated to 80 and 160 mg bid if the standing diastolic BP was greater than 90 mm Hg. BLood pressures on the last visit on placebo were compared to those on the last visit on oxprenolol. Standing BP declined from 145 +/- 4/108 +/- 1 to 130 +/- 4/98 +/- 4 on a mean dose of 256 mg of oxprenolol (p less than 0.001 syst.; p less than 0.01 diast.). Recumbent BP fell from 146 +/- 4/107 +/- 1 to 138 +/- 5/93 +/- 2 (p less than 0.06 syst.; p less than 0.01 diast.). During the final week, 13 of the 15 patients were admitted to the hospital for 24-hr monitoring of BP. The 24-hr BP readings showed a mean coefficient of variation of 6.6% recumbent and 7.2% standing. we conclude that bid oxprenolol will maintain 24 hr BP control in most patients.