Drugs online research references
Am Heart J. 1991 Jan;121(1 Pt 1):44-51.
Myocardial metabolic and hemodynamic effects of a sustained intravenous infusion of nifedipine with and without metoprolol in patients with unstable angina.
Melandri G, Branzi A, Tartagni F, Degli Esposti D, Piazzi S, Motta R, Bargossi A, Fallani F, Magnani B.
Institute of Cardiology, Bologna University, Italy.
We tested the usefulness of a sustained intravenous infusion of nifedipine and a combination of nifedipine and metoprolol in the early management of 14 patients with unstable angina pectoris. After a 24-hour run-in period, nifedipine was titrated in a stepwise fashion (mean dose 27 +/- 7 micrograms/min). After nifedipine treatment coronary blood flow increased from 150 +/- 66 to 183 +/- 74 ml/min (p less than 0.05), whereas double product, myocardial oxygen consumption, and both arterial and coronary sinus (nor)epinephrine levels were unchanged. Myocardial lactate uptake increased from 3.4 +/- 26.1 to 31.3 +/- 26.6 mumol/min (p less than 0.005) and free fatty acid uptake from 7.2 +/- 22.1 to 34.5 +/- 33.7 mumol/min (p less than 0.05). A small nonsignificant improvement in amino acid metabolism was observed. Metoprolol was added in seven patients and led to a decrease in double product (-2.2 +/- 1.6 x 10(3); p less than 0.01) and myocardial oxygen consumption (-3.2 +/- 3.8 ml/min; p less than 0.05). The lactate uptake/oxygen uptake ratio increased by 18% after metoprolol (p = NS). The number of episodes of chest pain decreased from 2.4 +/- 1.1/24 hours to 0.1 +/- 0.2 in the nifedipine group and from 2.9 +/- 1.1/24 hours to 0.3 +/- 0.5 in the nifedipine plus metoprolol group (both p less than 0.01). We conclude that in the acute phase of unstable angina, intravenous nifedipine can be carefully titrated to improve coronary blood flow and oxidative metabolism. The addition of metoprolol is also associated with a reduction in myocardial oxygen demand. This treatment results in significant hemodynamic stability.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1985376&dopt=Abstract
Crit Care Med. 1993 May;21(5):733-9.
Effects of dopexamine on hemodynamics and oxygen consumption after beta blockade in lambs.
Taylor BJ, Rogers BW, Sziszak TL, Sziszak TJ.
Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock 72205.
OBJECTIVES: Dopexamine is a synthetic catecholamine with predominantly beta 2 and dopaminergic adrenergic receptor activities. We investigated its effects on systemic and myocardial hemodynamics and oxygen consumption (VO2) in a newborn species and studied its predominant mechanism of action. DESIGN: Prospective dose-response study with each animal serving as it own control. SUBJECTS: Eight chronically instrumented, unanesthetized lambs, 9 to 11 days of age. INTERVENTIONS: After surgical instrumentation and recovery for 72 hrs, animals were infused with dopexamine at increasing doses (1, 10, and 100 micrograms/kg/min) for 5 mins each before and after beta 1 (metoprolol) and beta 1, beta 2 (propranolol) adrenergic receptor blockade. All studies were performed during normoxia. MEASUREMENTS AND MAIN RESULTS: Heart rate (HR) increased with increasing infusion rates of dopexamine and systemic arterial pressure and vascular resistance decreased. Cardiac index, left ventricular pressure development, and systemic VO2 were unchanged, as was the rate x pressure product. Left circumflex coronary artery blood flow and myocardial VO2 were unaltered. After beta 1-blockade, dopexamine produced an increase in HR and decreased systemic arterial pressure and vascular resistance. After beta 1-adrenergic receptor blockade, no change was noted in systemic or myocardial VO2, coronary blood flow, or rate x pressure product. After beta 1, beta 2-blockade with propranolol, increasing infusion rates of dopexamine resulted in decreases in systemic pressure and vascular resistance. CONCLUSIONS: Dopexamine produced significant cardiovascular effects mediated primarily by beta 2-adrenergic receptors, and also produced residual peripheral arterial vasodilation after combined beta 1- and beta 2-blockade. The latter finding suggests that dopaminergic receptor stimulation may partly mediate dopexamine's effects in newborn lambs.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8386999&dopt=Abstract
Clin Pharmacol Ther. 1996 Nov;60(5):493-503.
Jejunal permeability and hepatic extraction of fluvastatin in humans.
Lindahl A, Sandstrom R, Ungell AL, Abrahamsson B, Knutson TW, Knutson L, Lennernas H.
Department of Pharmacy, University of Uppsala, Sweden.
OBJECTIVES: The primary objective was to investigate the effective permeability and the hepatic extraction of fluvastatin, a new 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor, during a jejunal perfusion in humans. The secondary objective was to investigate the relationship between human jejunal effective permeability values and physicochemical properties for four different drugs. METHODS: Nine healthy male volunteers were included in the study, which consisted of two sequential study parts. In the first part, the jejunal effective permeability of fluvastatin, antipyrine, metoprolol, and atenolol was assessed with use of the regional jejunal perfusion approach (150 minutes, 2.0 ml/min). After a washout period of at least 5 days, the same subjects received an intravenous infusion of fluvastatin (20 minutes, 2.0 mg). Plasma samples were taken in both parts of the study and were analyzed for the content of fluvastatin. RESULTS: The mean hepatic extraction of fluvastatin was 67% after the jejunal perfusion and 73% after the intravenous infusion. The half-life of fluvastatin was approximately 60 minutes after both administration routes. The jejunal effective permeability and the fraction absorbed both correlated (r2 = 0.968, p < 0.05; and r2 = 0.994, p < 0.05) with the partition coefficient (log D, pH 6.5) but not with the molecular size or the hydrogen bond number. CONCLUSION: Fluvastatin is extracted by the liver to a large extent (about 70%) and has a short half-life after both oral and intravenous administration. In this study, the human jejunal effective permeability and the fraction absorbed for these four drugs were better predicted by log D (pH 6.5) than both the molecular size and the hydrogen bond number.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8941022&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