online pharmacy, prescription drugs online



Drugs online research references








Am J Physiol. 1994 Feb;266(2 Pt 2):H787-94.
Effects of metoprolol on left ventricular function in rats with myocardial infarction.

Cherng WJ, Liang CS, Hood WB Jr.

Cardiology Unit, University of Rochester Medical Center, New York 14642.

To study the effect of beta-receptor-blocking agents in an animal model of left ventricular (LV) dysfunction, we measured LV performance in vivo and in vitro in 69 rats with or without metoprolol (M) treatment 3 wk after left coronary arterial ligation or sham operation. Rats were divided into six groups including control (C) and M noninfarct (C-N and M-N), C and M small infarct (C-S and M-S), and C and M large infarct (C-L and M-L). LV function was measured as slope of change in systolic vs. diastolic pressure (pressure-function curve) during pressor response after administration of a bolus of phenylephrine (5 micrograms/kg i.v.). Reduction of LV function was noted in C-L compared with C-N and C-S (slope of pressure-function curve 3.3 +/- 0.3 vs. 11.0 +/- 1.9 and 11.9 +/- 2.3, respectively) and in M-L compared with M-N and M-S rats (slope of 5.5 +/- 1.4 vs. 11.3 +/- 2.0 and 12.1 +/- 1.4, respectively). There was no significant difference between C and M rats, although there was a trend toward partial correction of the pressure-function curves in M-L compared with C-L rats. In muscle bath preparations the uninfarcted LV posterior papillary muscle from shams and rats with small infarcts showed a dose-related increase in peak rate of tension development with isoproterenol stimulation, but this response was lacking in both C-L and M-L. Tissue assays showed no change in beta-receptor number.(ABSTRACT TRUNCATED AT 250 WORDS)

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8141380&dopt=Abstract




Am Heart J. 1996 Apr;131(4):772-7.
Effect of beta-blockade on left atrial contribution to ventricular filling in dogs with moderate heart failure.

Shimoyama H, Sabbah HN, Rosman H, Alam M, Goldstein S.

Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart and Vascular Institute, Detroit, MI 48202, USA.

Abnormal left ventricular (LV) filling has been observed in patients with heart failure. One feature of this abnormality is a reduction in the left atrial (LA) contribution to filling, a feature that can adversely affect overall LV stroke output. In this study we examined the effects of early, long-term monotherapy with the beta-blocker, metoprolol, on LA contribution to ventricular filling in dogs with moderate heart failure. LV dysfunction (ejection fraction 30 percent to 40 percent) was produced in 14 dogs by multiple, sequential intracoronary microembolizations. Dogs were randomized to 3 months' therapy with metoprolol (25 mg twice daily; n = 7) or to no therapy at all (control; n = 7). Mitral inflow velocity was measured before randomization and after completion of therapy by using pulsed Doppler echocardiography. The percentage of LA contribution to LV filling was calculated as the ratio of the time-velocity integral of the LA component of mitral inflow velocity (Ai) to the time-velocity integral of total diastolic inflow velocity (Ti) times 100. In control dogs, the percentage of LA contribution to filling decreased after 3 months of follow-up compared with that before randomization (14 percent +/- 3 percent vs 23 percent +/- 5 percent; p = 0.02). In contrast, in dogs treated with metoprolol, the percentage of LA contribution to filling increased after 3 months of therapy compared with that before randomization (26 percent +/- 3 percent vs 21 percent +/- 2 percent; p = 0.001). Therapy with metoprolol produced a decrease in LV end-diastolic pressure, end-diastolic wall stress and stiffness, and an increase in LA fractional shortening compared with no therapy at all. We conclude that early, long-term therapy with metoprolol improves LA contribution to LV filling. This beneficial effect is likely caused by the ability of beta-blockers to reduce LA workload and consequently improve LA performance.

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8721654&dopt=Abstract




Int J Clin Pharmacol Ther Toxicol. 1984 Jun;22(6):312-5.
Pharmacokinetics of lidocaine in healthy individuals pretreated with multiple doses of metoprolol.

Jordo L, Johnsson G, Lundborg P, Regardh CG.

The effect of pretreatment with multiple doses of 100 mg of metoprolol on the pharmacokinetics of lidocaine has been studied in six young healthy subjects. The lidocaine dose was 100 mg and the infusion time 12 minutes. Metoprolol had no effect on the levels or the time course of lidocaine in the plasma. The disposition characteristics of the antiarrhythmic agent were not significantly altered by metoprolol in these individuals. These results cannot be extrapolated to prolonged infusion of lidocaine in patients with myocardial infarction.

online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6746155&dopt=Abstract












online pharmacies || Hair Million herbal formula for hair loss and hair growth || Amoxicillin || Tramadol || Paxil || Rx Drugs USA, Prescription Drugs Online Pharmacy || Zithromax || online pharmacy || Antibiotics and prescription medications online literature || Antibiotics