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Biomedical subjects

C F George

Publications and source records attributed to C F George.

175 records · Page 10Linked to original sources
PubMed1970

Practolol in treatment of angina pectoris. A double-blind trial.

Twenty-four patients with angina pectoris entered a double-blind trial of the cardioselective beta-adrenergic blocking agent practolol. Seventeen experienced less angina and consumed fewer glyceryl trinitrate tablets when on the active preparation. There was also a decrease in the mean number of attacks suffered by patients while on practolol and a reduction in the number of glyceryl trinitrate tablets taken. These results are of statistical significance at, at least, the 5% level.

Acetanilides↗
PubMedDate not supplied

Propranolol.

Explore the source record for details and available documents.

Aminophylline↗
PubMedDate not supplied

Clinical consequences of abrupt drug withdrawal.

Syndromes due to the abrupt withdrawal of drug treatment occur mainly with adrenal corticosteroids and agents with an action on either the cardiovascular system or central nervous system. The abrupt withdrawal of antihypertensive therapy typically results in symptoms of overactivity in the sympathetic nervous system. Clonidine and beta-adrenoceptor antagonists are clinically the most important of these agents, but numerous other drugs have been implicated. Overall, the problem is small when viewed in the context of the huge scale of prescribing of antihypertensive medicines. A more serious problem is the occurrence of crescendo angina following the abrupt withdrawal of beta-adrenoceptor antagonists. Although other factors may be involved, adaptive up-regulation of beta-adrenoceptor density is the most likely cause of crescendo angina, and renders the patient more susceptible to sympathetic nervous stimulation following withdrawal of treatment. Besides leading to a recrudescence of the disease being treated, the withdrawal of corticosteroids can cause a variety of syndromes. In particular, problems can arise as a result of treatment-induced suppression of the hypothalamic-pituitary-adrenal (HPA) axis. Another steroid withdrawal syndrome of unknown aetiology, without significant abnormalities of the HPA axis occurring, has been described. Benign intracranial hypertension may rarely follow steroid withdrawal in children. The syndromes associated with withdrawal of drugs which have an action on the CNS are poorly understood. Withdrawal of neuroleptic drugs can be followed by symptoms that resemble those described following withdrawal of anticholinergic drugs, and those agents with the greatest muscarinic-receptor-blocking properties are those which are most frequently implicated. However, the less common withdrawal dyskinesias are thought to reflect up-regulation of dopaminergic receptors during long term treatment. Gastrointestinal symptoms predominate following the abrupt withdrawal of antidepressants but hypomania and an 'akathisia-like' syndrome have been reported. Barbiturates are no longer recommended as hypnotics because of severe effects of withdrawal and the existence of safer alternatives. Short acting barbiturates can be withdrawn by replacement with either phenobarbitone (phenobarbitol) or diazepam and subsequent gradual reduction in dose. The recognition of dependency on benzodiazepines has been slow because of the similarity of mild withdrawal symptoms to the original problem which led to treatment being offered.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal Cortex Hormones↗
PubMedDate not supplied

Diagnostic techniques in obstructive sleep apnea.

Only in the last 25 years has sleep apnea been recognized as a very common disorder and important cause of mortality. Overnight, attended polysomnography remains the reference diagnostic tool for sleep apnea, although the technology for diagnosis continues to evolve rapidly. In many instances, screening and ambulatory monitoring devices can provide similar, clinically relevant information, but larger validation studies including long-term clinical outcomes are necessary.

Diagnosis, Differential↗
PubMedDate not supplied

Drug metabolism by the gastrointestinal mucosa.

Circumstantial evidence for first-pass metabolism across the gastrointestinal mucosa includes reduced bioavailability after oral administration, despite complete or good absorption. There may also be route-dependent variation in the pattern of metabolism with the latter occurring to a greater extent after oral administration than after parenteral injection. However, direct proof that first-pass metabolism takes place across the gastrointestinal mucosa relies upon cannulation of either the portal or mesenteric venous tree. Such studies are not possible in most patients because of the potential hazards involved and the attendant ethical considerations. Additional information has come from the study of enzyme activity in biopsies of intestinal mucosa and experiments performed on isolated loops of intestine in various animal species. Although the former have identified the fact that enzyme activity may vary along the length of the intestine and the latter have provided quantitative information on what can occur in vivo, these data cannot be extrapolated to intact man. Both phase I (preconjugation) and phase II (conjugation) reactions have been described. However, except for oxidative deamination, e.g. tyramine and hydrolysis of esters such as pivampicillin and aspirin, phase I reactions appear to be quantitatively unimportant. In contrast, synthetic reactions are much more active. Sulphate conjugation, in particular, is important for the beta-adrenoceptor stimulants isoprenaline (isoproterenol), isoetharine and rimiterol, as well as for steroid hormones. Glucuronidation has also been demonstrated to occur in man for a small number of drugs. N-Acetylation is an important pathway and, as in the liver, there is evidence of polymorphism. Metabolism of hydralazine, isoniazid, p-aminosalicylic acid as well as certain sulphonamides by intestinal N-acetyl transferase has been demonstrated, but in all probability affects other drugs as well. Little is known concerning the physiological factors which alter the activity of the gastrointestinal drug-metabolising enzymes. However, significant drug-drug interactions have been demonstrated to occur at this site-particularly for drugs which undergo sulphate conjugation.

Analgesics, Opioid↗
PubMedDate not supplied

Effects of ischaemic heart disease, Crohn's disease and antimicrobial therapy on the pharmacokinetics of sulphinpyrazone.

The renewed interest in sulphinpyrazone in recent years has arisen from its potential to inhibit platelet aggregation. In vivo much of the activity is probably due to the thioether or sulphide metabolite which has a greater potency and a longer half-life than the parent compound. The sulphide metabolite is formed exclusively by the gut microflora in man. The pharmacokinetics of sulphinpyrazone (200 mg orally) have been studied, with particular attention to the formation of the sulphide metabolite, in groups of patients who might be expected to show abnormal formation of this active metabolite due to altered delivery of the drug to the lower gut or altered gut flora. Five patients studied 1 month after a myocardial infarction did not differ markedly from young, normal volunteers with respect to either sulphinpyrazone or its metabolite. Crohn's disease in the quiescent phase did not significantly alter the pharmacokinetics or metabolism of the drug, but 1 patient who had undergone a hemicolectomy formed negligible concentrations of the active metabolite. Antimicrobial therapy produced highly variable results with almost complete suppression of sulphide formation in some subjects but no apparent effect in others.

Adult↗
PubMedDate not supplied

Package inserts.

Research has shown that most people would like more information about their medicines. Almost all would welcome the idea of having a printed leaflet if it were written in simple terms. Such leaflets are now being incorporated with medicines which are prescribed in original packs.

Drug Industry↗