Plasma lipid profiles and antihypertensive agents: effects of lisinopril, enalapril, nitrendipine, hydralazine, and hydrochlorothiazide

Hydralazine augmented ultrasound hyperthermia for the treatment of hepatocellular carcinoma

This study investigates the use of hydralazine to enhance ultrasound hyperthermia for the treatment of hepatocellular carcinoma (HCC) by minimizing flow-mediated heat loss from the tumor. Murine HCC tumors were treated with a continuous mode ultrasound with or without an intravenous administration of hydralazine (5 mg/kg). Tumor blood flow and blood vessels were evaluated by contrast-enhanced ultrasound (CEUS) imaging and histology, respectively. Hydralazine markedly enhanced ultrasound hyperthermia through the disruption of tumor blood flow in HCC. Ultrasound treatment with hydralazine significantly reduced peak enhancement (PE), perfusion index (PI), and area under the curve (AUC) of the CEUS time-intensity curves by 91.9 ± 0.9%, 95.7 ± 0.7%, and 96.6 ± 0.5%, compared to 71.4 ± 1.9%, 84.7 ± 1.1%, and 85.6 ± 0.7% respectively without hydralazine. Tumor temperature measurements showed that the cumulative thermal dose delivered by ultrasound treatment with hydralazine (170.8 ± 11.8 min) was significantly higher than that without hydralazine (137.7 ± 10.7 min). Histological assessment of the ultrasound-treated tumors showed that hydralazine injection formed larger hemorrhagic pools and increased tumor vessel dilation consistent with CEUS observations illustrating the augmentation of hyperthermic effects by hydralazine. In conclusion, we demonstrated that ultrasound hyperthermia can be enhanced significantly by hydralazine in murine HCC tumors by modulating tumor blood flow. Future studies demonstrating the safety of the combined use of ultrasound and hydralazine would enable the clinical translation of the proposed technique.

Effects of lisinopril and bisoprolol on lipoprotein metabolism in patients with mild-to-moderate essential hypertension

The short- and long-term effects of the angiotensin-converting enzyme inhibitor lisinopril and the cardioselective beta-blocker bisoprolol on serum lipids, lipoproteins, apolipoproteins, and lipoprotein(a) (Lp[a]) levels were investigated in patients with mild-to-moderate essential hypertension. Fifty-two patients completed the 12-month, randomized, multicenter trial. After administration of lisinopril (10 to 20 mg/d; n = 24) and bisoprolol (2.5 to 10 mg/d; n = 28), systolic and diastolic blood pressures decreased significantly (P < 0.01) from baseline in both groups at 3, 6, and 12 months. The reduction in diastolic blood pressure was significantly (P < 0.05) greater in the lisinopril group than in the bisoprolol group only at 6 months. Heart rates dropped significantly in the bisoprolol group but not in the lisinopril group. No significant changes in lipids, lipoproteins, apolipoproteins, or Lp(a) levels were observed with either drug at 3, 6, or 12 months, and no significant differences were noted between the two drugs for these parameters. We conclude that lisinopril and bisoprolol are effective as antihypertensive drugs without adverse metabolic effects after short- and long-term treatment in patients with mild-to-moderate essential hypertension.

A multicentre, hospital study of the efficacy and safety of terazosin and its effects on the plasma cholesterol levels of patients with essential hypertension

The safety, efficacy and the effect on the plasma total cholesterol of once-daily terazosin hydrochloride administered either as monotherapy or in combination with other antihypertensive therapy were evaluated in patients with mild-moderate uncontrolled essential hypertension in this U.K., open, multicentre hospital, 3-month study. Patients initially received 1 mg of terazosin as monotherapy or in addition to their current antihypertensive therapy followed by dose titration, if necessary, to a maximum of 10 mg over the first 6 weeks depending upon blood pressure control. Patients then continued treatment for a further 6 weeks on their optimum dosage. There were highly significant mean reductions in systolic and diastolic blood pressures at the end of 12 weeks for 439 patients of 18.5 and 14.0 mmHg (P less than 0.001), respectively, and were similar to the reductions shown when subgrouping the patients into either those 197 patients who were treated with terazosin as monotherapy (17.6/13.7 mmHg, P less than 0.001) or those 242 patients treated with terazosin in combination with other antihypertensive agents (19.3/14.2 mmHg, P less than 0.001). In addition, in a sub-group of 132 patients who had their mean total cholesterol measured at the end of 12 weeks' treatment, there was a significant reduction of -0.4 mmol/l (P less than 0.01). A similar significant mean reduction for total cholesterol was also shown when this subgroup was divided into those 50 patients who were treated with terazosin as monotherapy (-0.56 mmol/l, P less than 0.01), but not for those 82 patients treated with terazosin in combination with other antihypertensive agents (-0.3 mmol/l, P greater than 0.05 less than 0.1). No serious toxicity or safety problems were observed. Once daily administration of terazosin, either as monotherapy or in combination with other antihypertensive agents, proved to be safe and effective in reducing the blood pressure of patients with uncontrolled mild-moderate essential hypertension and favourably reduced the total plasma cholesterol level.

Antihypertensive agents, serum lipoproteins and glucose metabolism

Effective blood pressure control with traditional high-dose diuretic therapy has led to a distinct decrease in cerebrovascular morbidity and mortality, but failed to achieve a satisfactory reduction of coronary complications and sudden death. The same applies also for beta blockers, although they have been shown to be effective in secondary prevention of myocardial infarction. It is suspected that conventional antihypertensive treatment has an unfavorable effect on coronary risk factors other than hypertension. For instance, thiazide-type diuretics can impair glucose tolerance and increase the potentially atherogenic serum low-density lipoprotein (LDL) cholesterol fraction and triglycerides. Beta blockers without partial intrinsic sympathomimetic activity increase serum triglycerides and tend to lower the potentially antiatherogenic high-density lipoprotein (HDL) cholesterol. Certain beta blockers may also impair glucose tolerance, particularly when they are combined with diuretics. Calcium channel blockers, angiotensin converting-enzyme inhibitors and alpha 1-receptor blockers do not adversely affect lipoprotein or carbohydrate profiles. The latter two drug classes may even increase insulin sensitivity, and alpha 1 blockers may also slightly improve lipid metabolism. The prognostic relevance of drug-induced dyslipidemia and/or glucose intolerance awaits further clarification. In the meantime, it is of clinical interest that several of the generally available antihypertensive drugs seem to be metabolically neutral or sometimes perhaps even potentially beneficial with regard to the lipoprotein and carbohydrate metabolism.

Antihypertensive effect and pharmacokinetics of nitrendipine in children

Nitrendipine, a new calcium-channel antagonist, was used to treat 25 children (aged 6 months to 17 years) with severe hypertension. Systolic and diastolic blood pressures (mean +/- SEM) fell from 148 +/- 2/99 +/- 2 mm Hg to 128 +/- 4/77 +/- 3 mm Hg after 24 hours and to 121 +/- 2/75 +/- 2 mm Hg after 2 weeks. No further reductions in systolic or diastolic blood pressure were observed after continued therapy. Transient reflex tachycardia occurred during the first week of therapy. Other adverse effects were uncommon and included headaches, flushing, palpitations, and edema. Pharmacokinetic parameters were estimated at steady state after an oral dose of 0.56 +/- 0.04 mg/kg in 13 children. Although absolute oral bioavailability could not be determined, estimates of the area under the plasma concentration versus time curve, the apparent peak serum concentration, and the apparent time at which the peak serum concentration occurred indicated that both the rate of absorption and oral bioavailability are variable. Coadministration of nitrendipine with food decreased the rate of absorption and may have reduced oral bioavailability. A relationship between age and the apparent plasma elimination half-life of nitrendipine was not observed. Nitrendipine, 0.25 to 0.5 mg/kg per dose administered orally every 6 to 12 hours, appeared to be an effective and safe treatment for resistant hypertension in infants and children.