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Propranolol plasma levels and relief of migraine. Relationship between plasma propranolol and 4-hydroxypropranolol concentrations and clinical effects.

The relationship between propranolol and 4-hydroxypropranolol plasma concentrations and relief of migraine was assessed in 17 patients during treatment with oral racemic propranolol hydrochloride in doses of 40 to 240 mg/day. Propranolol decreased the migraine index more than 70% in 13 patients: five patients at a dosage of 40 mg/day, five patients at a dosage of 120 mg/day, and three patients at a dosage of 240 mg/day. Three patients did not achieve a good improvement of migraine at any of the doses used. The relief of migraine was not directly related to the propranolol and 4-hydroxypropranolol plasma concentrations.

Adult↗

Increase in plasma propranolol caused by nicardipine is dependent on the delivery rate of propranolol.

The influence of a single oral dose of nicardipine 30 mg on the pharmacokinetics and pharmacodynamics of propranolol 80 mg given as a conventional release formulation and as a slow release formulation was studied in two separate groups of 12 healthy volunteers. Nicardipine doubled the area under the curve (AUC) and Cmax of propranolol when given as a conventional formulation, but increased it only slightly when given as a slow release formulation. This pharmacokinetic interaction did not result in clinically relevant changes in pharmacodynamic responses. These results indicate that the enhancement of the bioavailability of propranolol by coadministration of nicardipine is dependent on the delivery rate of propranolol, suggesting that the interaction is mainly due to short-term haemodynamic effects of nicardipine leading to saturation of hepatic enzymes or functional shunting.

Adrenergic beta-Antagonists↗

Effect of propranolol versus no propranolol on total mortality plus nonfatal myocardial infarction in older patients with prior myocardial infarction, congestive heart failure, and left ventricular ejection fraction > or = 40% treated with diuretics plus angiotensin-converting enzyme inhibitors.

At 32-month follow-up of older patients with prior myocardial infarction, congestive heart failure, and a left ventricular ejection fraction > or = 40% treated with diuretics plus angiotensin-converting enzyme inhibitors, and also with digoxin if atrial fibrillation was present, propranolol caused a 35% significant reduction in total mortality and a 37% significant decrease in total mortality plus nonfatal myocardial infarction compared with no propranolol. At 1-year follow-up, propranolol caused a significantly greater increase in left ventricular ejection fraction (6%) and a significantly greater reduction in left ventricular mass (34 g) than did no propranolol (2% and 20 g, respectively).

Adrenergic beta-Antagonists↗

Comparison of propranolol LA 80 mg and propranolol LA 160 mg in migraine prophylaxis: a placebo controlled study.

Thirty patients with severe classical and common migraine participated in a double-blind placebo-controlled cross-over study of migraine prophylaxis with propranolol LA (long-acting) 80 mg once daily, or propranolol LA 160 mg once daily or placebo. Each treatment was given for two months. There were no significant differences between the three treatment periods in headache frequency, headache severity, nausea frequency or severity. There was a non-significant trend for reduced duration of headache with the two doses of propranolol. The possible reasons for this negative effect are discussed. The safety of propranolol and its lack of serious side effects were demonstrated.

Adolescent↗

Antihypertensive effect of propranolol in conscious spontaneously hypertensive rats: central hemodynamics, plasma volume, and renal function during beta-blockade with propranolol.

In order to obtain a better insight into the hemodynamic changes during beta-blockade, we measured central hemodynamics, plasma volume, and renal function during both acute and long-term beta-blockade in conscious spontaneously hypertensive rats (SHR). Acutely, both 1 and 5 mg/kg propranolol immediately decreased heart rate (HR) and cardiac output (CO). However, total peripheral resistance (TPR) rose sharply, thus preventing mean arterial pressure (MAP) from falling during the first hours after injection. After 4 h TPR had returned to control values and, because CO was still reduced, MAP was lowered. This decrease of MAP persisted for more than 20 h. During 5-day infusion of propranolol (5 mg/kg/day) CO fell on the 1st day and remained lowered during the 5-day period. MAP was lowered from the second day onward. Despite the reduced CO and MAP, plasma volume (PV) did not increase during the 5-day infusion. Acute injection of 5 mg/kg/day did, however, result in a decreased PV at 1 h postinjection. In this time span central venous pressure remained unchanged. Quantitation of water and sodium excretion revealed an immediate diuresis and natriuresis after acute administration of propranolol. This occurred despite a reduced glomerular filtration rate and effective renal plasma flow, as quantitated by indicator clearance methods. We conclude that propranolol reduced tubular sodium reabsorption, possibly through blockade of tubular beta-receptors. This effect may be essential for the long-term antihypertensive efficacy of beta-blockers because it prevents sodium and water retention in a state of reduced MAP and CO.

Animals↗

Inhibition of CYP2D6 activity by treatment with propranolol and the role of 4-hydroxy propranolol.

1. The 4-hydroxylation of propranolol by rat and human liver microsomes is associated with formation of a chemically reactive species which binds irreversibly to cytochrome P4502D6 (CYP2D6) destroying its catalytic function. Therefore, the effect of propranolol treatment (80 mg twice daily) on debrisoquine phenotype was examined, to see if it resulted in phenocopying in vivo. The role of 4-hydroxypropranolol (4OHP) in the inhibition of CYP2D6 activity was also studied using microsomes from yeast expressing CYP2D6 and from human livers; metoprolol was used as the CYP2D6 substrate. 2. Although a significant effect on apparent oxidation phenotype was demonstrated, the absolute change in the urinary debrisoquine/4-hydroxydebrisoquine ratio (D/4HD) was small, such that no extensive metaboliser who received propranolol treatment was reclassified as a poor metaboliser. The in vitro studies indicated that 4OHP is a potent inhibitor of metoprolol metabolism (Ki approximately 1 microM). This inhibitory effect was enhanced when 4OHP was pre-incubated in the presence of a NADPH generating system and human liver microsomes. The effect was decreased significantly when reduced glutathione was added to the pre-incubation mixture. Metabolism of 4OHP occurred when incubated with human liver microsomes in the presence of a NADPH generating system and irrespective of CYP2D6 phenotype; yeast expressing CYP2D6 did not metabolise 4OHP. 3. We conclude that, although treatment with propranolol 80 mg twice daily significantly decreases the catalytic function of CYP2D6, the inhibition is insufficient to result in phenocopying. The reactive intermediate produced by further metabolism of 4OHP is probably scavenged effectively in vivo by glutathione and other nucleophiles.

Adult↗

Effects of (+/-)-sotalol, (+/-)-propranolol, and (-)-propranolol on norepinephrine release upon hepatic nerve stimulation in the dog liver in vivo.

The study was carried out to determine whether the diminished release of norepinephrine (NE) upon sympathetic activation in the presence of sotalol can be attributed to the blockade of beta-adrenoceptors in the liver. NE release from the liver was measured in hepatic venous blood collected during direct hepatic nerve stimulation in anesthetized dogs. The mean basal NE concentration in hepatic venous and aortic blood was 0.046 +/- 0.003 and 0.244 +/- 0.041 ng/mL, respectively. NE release increased significantly as stimulation frequency increased, while aortic NE concentration remained unchanged. The increasing response of NE release upon stimulation in the vehicle control group remained stable during the whole experimental period. In dogs treated with sotalol (5 mg/kg, i.v.), NE release was reduced approximately by 30-43%, and the difference was statistically significant (P less than 0.01) at 8 Hz. (+/-)-Propranolol (2.5 mg/kg, i.v.) tended to diminish it, but the difference was not significant. (-)-Propranolol (0.1 mg/kg, i.v.) did not alter NE release at any frequency tested. The beta-blocking action of these drugs in the liver, as determined by the antagonism against the hepatic arterial vasodilating response to isoproterenol, was most effective with (+/-)-propranolol (100%), followed by (-)-propranolol (90%) and sotalol (70%). The results suggest that the inhibitory effect of sotalol on NE release may be related to a mechanism other than its beta-blocking action in the dog liver.

Animals↗

Protection of ischemic myocardium: comparison of effects of propranolol, bevantolol and N-dimethyl propranolol on infarct size following coronary artery occlusion in anesthetized dogs.

The relative extent of myocardial infarction produced by occlusion of the left anterior descendens coronary artery in anesthetized dogs was determined under control conditions or following treatment (4 h after ligation) with propranolol (1 mg/kg), bevantolol (3 mg/kg) or N-dimethyl propranolol (10 mg/kg). Doses of drugs were selected to provide similar reductions in heart rate, aortic blood pressure and contractility. Infarct size was estimated indirectly from levels of plasma creatine phosphokinase and measured histochemically by nitroblue tetrazolium stain. A significant ( p < 0.001) correlation between methods was found. Propranolol and bevantolol (beta adrenergic antagonists) produced a significant (p < 0.05) reduction (approximately 50% decrease) in infarct size, measured at 8 h following induction of ischemia, while N-dimemthyl propranolol (no beta antagonist activity) produced no effect. While all three agents produced similar hemodynamic actions and thereby reduced primary determinants of myocardial oxygen demand, only the beta blockers were able to afford protection of ischemic myocardium.

Adrenergic beta-Antagonists↗

[Comparison of the effects of diazepam, nifedipine, propranolol and a combination of nifedipine and propranolol, by sublingual administration, in patients with hypertensive crisis].

PURPOSE: To evaluate the effects of sublingual administration of diazepam, nifedipine, propranolol and the association of nifedipine with propranolol patients with hypertensive crisis. METHODS: Eighty patients with hypertensive crisis, DAP greater than 120 mmHg, and mean age of 54 +/- 7.4 years, 33 women and 47 men, were evaluated. The AP was measured with an aneroid sphygmomanometer, in mmHg, in orthostatic position, before and after 10, 20, 30 and 60 minutes of treatment. The heart rate in one minute was also measured at the same intervals. The patients were divided randomly into four groups and treated, respectively, with 10 mg of diazepam, 10 mg of nifedipine, 40 mg of propranolol and 10 mg of nifedipine associated with 40 mg of propranolol. RESULTS: A significant and gradual reduction of SAP and DAP were observed in all groups of patients. The percentage of reduction, after 60 minutes, for SAP was, respectively, 10.1%, 12.9%, 15.4% and 16%, and for DAP 7.7%, 11.3%, 13.6% and 13% in groups I to IV. The heart rate did not change in groups I and II, but significative reduction was observed in groups III (p = 0.002) and IV (p = 0.009). CONCLUSION: The drugs used were effective for the treatment of hypertensive crisis, and the sublingual administration is an important and easy way for their administration.

Administration, Sublingual↗

Pharmacokinetic data of propranolol enantiomers in a comparative human study with (S)- and (R,S)-propranolol.

The pharmacokinetics of (S)-propranolol were compared after the oral administration of a 40 mg dose of the pure enantiomer and an 80 mg dose of a racemic mixture of (R,S)-propranolol. The results of this study indicate that the bioavailability of (S)-propranolol, as expressed by the mean area under the concentration-time curve (AUC) and maximum serum concentration, is lower after 40 mg of the optically pure drug than after the racemic drug.

Adult↗

Quantitative determination of propranolol, propranolol glycol and N-desisopropylpropranolol in brain tissue by electron capture gas chromatography.

A method for the quantitative determination of propranolol and two of its active metabolites, 3-(alpha-naphthoxy)-1,2-propanediol (propranolol glycol) and N-des-isopropylpropranolol, in brain tissue of mice is described. Tissues are homogenized in perchloric acid-acetonitrile. Propranolol and its metabolites are isolated from the supernatant by solvent extraction and separated and detected as their trifluoroacetyl derivatives by electron capture gas chromatography. Chemical structures of the derivatives were confirmed by gas chromatography-mass spectrometry. The electron capture detector response of all three compounds is high, 0.7-2.0 X 10(-16) moles/sec. Brain levels of 10-250 ng/g can be detected of all three compounds with high specificity and good precision.

Animals↗

Comparison of propranolol and propranolol LA in hypertension using 24-hr noninvasive blood pressure monitoring.

The technique of non-invasive blood pressure monitoring was used to compare the 24-hr control of blood pressure in 10 patients with essential hypertension taking either twice daily propranolol or a once daily long-acting formulation of propranolol (propranolol LA). Both drug regimes produced smooth control of blood pressure and heart rate through the 24 hours and significantly reduced blood pressure and heart rate on bicycle ergometry tests. There was no significant difference between the two treatments. The non-invasive oscillometric method of measuring 24-hr control of blood pressure provides an alternative to ambulatory intra-arterial monitoring.

Adult↗

Propranolol in schizophrenia. II. Clinical and biochemical aspects of combining propranolol with chlorpromazine.

Ten hospitalized chronic schizophrenic patients were given chlorpromazine alone and chlorpromazine plus high dose propranolol in two 7-week treatment periods according to a randomized crossover design. In the six patients who completed the whole study, plasma levels of chlorpromazine and chlorpromazine sulphoxide, total serum levels of neuroleptic and serum levels of prolactin were consistently and significantly elevated during treatment with chlorpromazine plus propranolol relative to levels during treatment with chlorpromazine alone. These effects are sufficient to explain previously reported clinical improvement in schizophrenic patients given propranolol in addition to neuroleptics.

Adult↗

Propranolol in schizophrenia: a double blind, placebo controlled trial of propranolol as an adjunct to neuroleptic medication.

A double blind, placebo controlled trial was carried out to examine the contribution of propranolol as an adjunct to neuroleptic medication in the treatment of chronic schizophrenic patients whose florid symptoms had not remitted with neuroleptic medication alone. Propranolol was shown to have a more beneficial effect than placebo, but the results were much less dramatic than those which have been described in previous studies. Recent work has shown that there may be a pharmacokinetic interaction between propranolol and neuroleptics, and this should be considered as one possible explanation of our findings.

Adult↗

Side-chain metabolism of propranolol: involvement of monoamine oxidase and aldehyde reductase in the metabolism of N-desisopropylpropranolol to propranolol glycol in rat liver.

The further metabolism of N-desisopropylpropranolol (NDP), a side-chain metabolite of propranolol (PL), was investigated in isolated rat hepatocytes. Propranolol glycol (PGL) was generated from NDP as a major metabolite. Naphtetrazole (NTE), a potent inhibitor of monoamine oxidase (MAO), significantly retarded the disappearance of NDP from the incubation medium, suggesting the involvement of MAO in the deamination of NDP to an aldehyde intermediate. In a reaction mixture of rat liver mitochondria and cytosol with NADPH, phenobarbital, a specific inhibitor of aldehyde reductase, and 4-nitrobenzaldehyde (4-NBA), a substrate inhibitor of aldehyde reductase, decreased the formation of PGL from NDP. 4-NBA was a competitive inhibitor of the enzyme responsible for the PGL formation. The optimal pH for the formation of PGL from NDP in the reaction mixture was approximately 8.0. Based on these results, we propose the possibility that, in the rat liver, MAO catalyzes the oxidative deamination of NDP to an aldehyde intermediate and the formed aldehyde intermediate is subsequently reduced to PGL by aldehyde reductase. Furthermore, the enantioselective metabolism of NDP to PGL was examined. In isolated rat hepatocytes, the amount of PGL formed from S-NDP [S(-)-form of NDP] was larger than that of PGL formed from R-NDP [R(+)-form of NDP].

Aldehyde Reductase↗

Propranolol and propranolol-LA in essential tremor: a double blind comparative study.

In a double blind, comparative study with 15 patients, a long-acting formulation of propranolol taken once daily (at doses of 160, 240 and 320 mg), was shown to be as effective as conventional propranolol (80 mg three times daily) in reducing the amplitude of essential tremor. The specific protocol employed demonstrated problems inherent in chronic pharmacological trials in essential tremor which have implications for future studies.

Adolescent↗

Comparison of a once daily long-acting formulation of propranolol with conventional propranolol given twice daily in patients with mild to moderate hypertension.

The effect of conventional propranolol tablets given twice daily has been compared with an equivalent dosage of a long-acting formulation of propranolol ('Inderal' LA)p given once daily in twenty-nine patients with mild to moderate hypertension. The study lasted 10 weeks. There was no significant difference in clinical response to the two treatments which were equally effective and well tolerated. A once daily dosage schedule should greatly aid patient compliance.

Adult↗