Cimetidine and Bioavailability of Propranolol

Donovan, MA; Heagerty, AM; Patel, L.; Castleden, M.; Pohl, J. E. F.

doi:10.1016/s0140-6736(81)90761-3

Cited by 40 publications

(6 citation statements)

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“…Au contraire, les médicaments qui réduisent l'activité microsomiale tels que la cimétidine diminuent l'extraction hépatique et augmentent les taux plasmatiques. 4 4. Contre-indications Elles découlent des propriétés des BB: insuffisance cardiaque aiguë, hypovolémie, blocs auriculo-ventriculaires des 2ème et 3ème degrés en l'absence d'entraînement électrosystolique.…”

Section: Effets Vasodilatateursunclassified

Intérêt des bêta-bloquants en médecine périopératoire. Première partie: notions fondamentales

Piriou

Aouifi

Lehot

2000

Can J Anesth/J Can Anesth

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Objectif : Rappeler les notions de pharmacologie et de physiopathologie nécessaires à l'utilisation des bêta-bloquants (BB) en médecine périopératoire.Sources : Recherche manuelle et informatisée de la littérature. (mots-clés : anesthesia and beta-blocker, surgery and beta-blocker).Constatations principales : Les BB cardiosélectifs bloquent préférentiellement les bêta-1 récepteurs, induisant une diminution de la fréquence cardiaque et de l'inotropisme, conduisant à la diminution de la consommation d'oxygène myocardique. Les BB non cardiosélectifs bloquent également les bêta-2 récepteurs, induisent une élé-vation des résistances vasculaires périphériques et bronchiques et augmentent les contractions utérines. Cependant, certains BB possèdent des effets vasodilatateurs (carvédilol, céliprolol, labétalol). Les contre-indications des BB résultent logiquement de leurs effets pharmacologiques. Le traitement BB tend à augmenter la densité des bêta-récepteurs membranaires, expliquant les manifestations d'hyperactivité du système nerveux sympathique observées lors de leur sevrage. Depuis la découverte du propranolol en 1964, les BB ont connu des fortunes diverses en anesthésie. Initialement, la sympatholyse partielle qu'ils induisent a été redoutée dans les situations de stress provoquées par les agents anesthésiques et surtout les manipulations chirurgicales. Cependant, les travaux publiés à partir de 1973 ont suggéré un effet hémodynamique protecteur. Conclusion :Les travaux récents ont démontré le caractère bénéfique de la poursuite des traitements BB jusqu'à l'anesthésie à l'exception des manifestations d'intolérance telles que l'hypotension ou la bradycardie sévère.Purpose: To review the pharmacologic and pathophysiologic information necessary to prescribe beta-blockers (BB) in perioperative medicine. Data source: Manual retrieval and electronic research of the literature using MEDLINE (key-words: anesthesia and beta-blocker; surgery and beta-blocker).Data synthesis: Cardioselective BB inhibit preferentially beta-1 receptors, inducing a decrease in heart rate and cardiac inotropism leading to reduction of oxygen myocardial consumption. Non-cardioselective BB inhibit also beta-2 receptors, increasing bronchial and peripheral vascular resistances and uterine contractions. However, some BB are also vasodilators (carvedilol, celiprolol, labetalol). Contraindications to BB result logically from their pharmacological effects. Treatment with BB increases membrane beta-receptor density; this explains sympathetic overactivity observed during weaning of treatment. Since the discovery of propranolol in 1964, the use of BB has been controversial in anesthesia. Formerly, the adverse effects of partial sympatholysis during anesthesia and surgery were feared. However, since 1973, experimental and clinical data have suggested a protective hemodynamic effect.Conclusion: Continued administration of BB up to the time of anesthesia has been encouraged except in patients with signs of intolerance such as hypotension or excessive bradyca...

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Section: Effets Vasodilatateursunclassified

Intérêt des bêta-bloquants en médecine périopératoire. Première partie: notions fondamentales

Piriou

Aouifi

Lehot

2000

Can J Anesth/J Can Anesth

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“…The effects of cimetidine on tolbutamide disposition in healthy volunteers appear to be vari- Donovan et at (1981); Kirch et at (1981); Mutschler et al (1984); Reimann et at (1982); Warburton et at (1979) Metoprolol tc;tAUC;ttv. No effect No ADRAC (1982); Chellingsworth et al (1988); Ellis et at (1984); Kirch et al (1981); Mutschler et at (1984) able and possibly dependent on the dosage of cimetidine studied.…”

Section: Other Agentsmentioning

confidence: 99%

Clinical Relevance of Cimetidine Drug Interactions

Shinn

1992

Drug Safety

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The excellent efficacy and tolerability profiles of H2-antagonists have established these agents as the leading class of antiulcer drugs. Attention has been focused on drug interactions with H2-antagonists as a means of product differentiation and because many patients are receiving multiple drug therapy. The main mechanism of most drug interactions involving cimetidine appears to be inhibition of the hepatic microsomal enzyme cytochrome P450, an effect which may be related to the different structures of H2-antagonists. Ranitidine appears to have less affinity than cimetidine for this system. There have been many published case reports and studies of drug interactions with cimetidine, but many of these have provided pharmacokinetic data only, with little information concerning the clinical significance of these findings. Nevertheless, the coadministration of cimetidine with drugs that have a narrow therapeutic margin (such as theophylline) may potentially result in clinically significant adverse effects. The monitoring of serum concentrations of drugs coadministered with cimetidine may reduce the risk of adverse events but does not abolish the problem. However, for most patients, concomitant administration of cimetidine with drugs possessing a wide therapeutic margin is unlikely to pose a significant problem.

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“…The elimination of many drugs is affected by cimetidine, including warfarin (Silver & Bell 1979), diazepam (Klotz & Reimann 1980), phenytoin (Hetzel et al 1981) and propranolol (Donovan et al 1981). The elimination of many drugs is affected by cimetidine, including warfarin (Silver & Bell 1979), diazepam (Klotz & Reimann 1980), phenytoin (Hetzel et al 1981) and propranolol (Donovan et al 1981).…”

Section: Cimetidine and Related Drugsmentioning

confidence: 99%

P450 Enzymes

Murray

1992

Clinical Pharmacokinetics

153

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Multiple hepatic P450 enzymes play an important role in the oxidative biotransformation of a vast number of structurally diverse drugs. As such, these enzymes are a major determinant of the pharmacokinetic behaviour of most therapeutic agents. There are several factors that influence P450 activity, either directly or at the level of enzyme regulation. Drug elimination is decreased and the incidence of drug interactions is increased when there is competition between 2 or more drugs for oxidation by the same P450 enzyme. The available knowledge concerning the relationship between the presence of certain functional groups within the drug structure and inhibition of P450 activity is increasing. In many instances, it is possible to associate inhibition with certain drug classes, e.g. antimycotic imidazoles and macrolide antibiotics. Disease states, especially those with hepatic involvement, and the genetic makeup of the individual are conditions in which some P450s may be downregulated (that is, the enzyme concentrations in liver are decreased), with associated slower rates of drug elimination. In these individuals, dosages of drugs that are substrates for downregulated P450s should be decreased. Exposure to environmental pollutants as well as a large number of lipophilic drugs can result in induction (upregulation) of P450 enzyme activity. This raises the issue of previous approaches to the study of P450 induction in vivo. The use of human hepatocyte preparations in culture is a promising new direction that could assist the determination of modifications to drug therapy necessitated by exposure to inducing agents. Until such information is obtained, however, the use of drugs known to increase the microsomal expression of particular P450s, and increase associated drug oxidation capacity in humans, should be used with caution.

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Cimetidine and Bioavailability of Propranolol

Cited by 40 publications

References 0 publications

Intérêt des bêta-bloquants en médecine périopératoire. Première partie: notions fondamentales

Intérêt des bêta-bloquants en médecine périopératoire. Première partie: notions fondamentales

Clinical Relevance of Cimetidine Drug Interactions

P450 Enzymes

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