Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1323099 (sympathomimetic)
 2,957 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The acute pulmonary and cardiovascular effects of pirbuterol dihydrochloride 10 mg and 15 mg, a new orally active beta 2-selective sympathomimetic agent, were compared with those of placebo and metaproterenol 20 mg over a period of seven hours in 24 stable asthmatics. Pirbuterol 15 mg and metaproterenol 20 mg had a comparable onset of action (30 min) and magnitude of peak bronchodilator effect (29 +/- 5 mean % increase in FEV1) but the bronchodilatation following pirbuterol was longer lasting (seven hours) than that following metaproterenol (three hours). Pirbuterol 15 mg also caused a greater magnitude and duration of bronchodilatation than pirbuterol 10 mg. No effect on heart rate or PEP/LVET ratio was noted with either drug. Side effects reported following each of the active agents were comparable in frequency and were almost always mild. These findings indicate that pirbuterol is an effective bronchodilator with a relatively long duration of action, definite beta 2-adrenergic specificity and insignificant toxicity when administered in a single dose.
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PMID:Acute bronchial and cardiovascular effects of oral pirbuterol and metaproterenol. 55

Hemodynamic studies have demonstrated a significantly reduced beta 1-adrenoceptor stimulating effect of prenalterol compared to dobutamine suggesting a partial agonism on the receptor. In order to prove this hypothesis we administered 80 micrograms/kg of prenalterol within 5 minutes in 8 healthy volunteers during a continuous infusion of dobutamine (15 micrograms/kg/min). In addition to heart rate, blood pressure and the double product, the systolic time intervals QS2I, PEP and LVET and the echocardiographically determined parameters FS and Vcf were measured for evaluation of ventrical function. The injection of prenalterol caused a distinct attenuation of the cardiostimulating effects of dobutamine: there was a prompt fall in heart rate and systolic blood pressure and a typical negative inotropic effect on the parameters of left ventricular function. In the experimental conditions selected, the effects of prenalterol were those of a beta-sympatholoytic agent. Prenalterol should therefore be classified as a partial beta 1-adrenoceptor agonist or as a beta-blocking agent with pronounced intrinsic sympathomimetic activity. The beta 1-stimulating potency of prenalterol amounts to about 60% of a full agonist.
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PMID:Prenalterol: a partial beta 1-adrenoceptor agonist or a beta-blocker with intrinsic activity? 285 52

Circulatory effects of bopindolol, a new nonselective beta blocking agent with intrinsic sympathomimetic activity and atenolol were compared. After baseline and first dose measurements atenolol 25 mg twice daily and bopindolol 1 mg daily were given to 10 healthy young subjects. Haemodynamic measurements were made noninvasively using echocardiography and systolic time intervals. Clinical and circulatory indices were measured at baseline, after initial dose and after one week of regular treatment at rest and at isometric handgrip exercise (IE) (HG). Atenol reduced the heart rate from 62 bpm to 49 and blunted totally the HR increase during IE (p less than 0.01). Bopindolol caused a 10% fall in heart rate (NS) at rest and a 15% fall (p less than 0.05) during IE. BP fell by 6% after atenol administration and 4% after bopindolol (NS) at rest and similarly during IE. In contrast to bopindolol, atenolol caused small increases initially in left ventricular end-diastolic dimension (LVEDD) and left ventricular end-systolic dimension (LVESD). A 10% increase in FS was seen at rest after bopindolol administration (NS). With the fall in heart rate the estimated cardiac output (CO) also fell from 3.66 to 3.151/min (P less than 0.05) after atenolol but rose from 3.87 to 3.93 after bopindolol (NS) during chronic treatment. Consecutively the total peripheral resistance (TPR) was increased to some extent by atenolol, whereas bopindolol reduced it at rest and during IE. A similar response was also found in systolic time intervals PEP/LVET which were reduced during bopindolol administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Haemodynamic effects of atenolol and bopindolol at rest and during isometric exercise. A non-invasive study in healthy volunteers. 290 79

Two studies of systolic time intervals (STIs) in patients with mild to moderate hypertension (HBP) revealed that no mean change in systolic intervals occurred with pindolol therapy, although some patients had significant alterations in their STIs. Pindolol responders with normal pretreatment preejection period to left ventricular ejection time (PEP/LVET) ratios had a significant increase in this ratio following pindolol therapy, whereas those with abnormal pretreatment PEP/LVET ratios had improvement in this ratio on administration of the drug. Patients on propranolol showed no change in PEP/LVET ratio. Propranolol administration slowed heart rate and lengthened Q-S2, S1-S2, and LVET, however, without altering the Q-S2 and LVET index, indicating that the changes were caused by the effect of propranolol on the heart rate alone. Chlorthalidone in high doses significantly reduced the Q-S2 index and the S1-S2 index, indicating that these changes were not caused by alteration of the heart rate. The second study suggests that STIs may provide a predictive clue for clinical response to pindolol. Patients with normal cardiac function (group I) are more likely to respond to pindolol than are those with abnormal cardiac function (group II). Directionally opposite changes in STIs in the two subgroups suggest different mechanisms for changing cardiac function. Pindolol's dual role as a beta-blocking agent with intrinsic sympathomimetic activity is proposed as a possible explanation, beta-blocking effects predominating in group I and sympathomimetic activity balancing the beta effect in group II.
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PMID:Pindolol and systolic time intervals in patients with hypertension. 710 32

After single i.v. (5 and 10 mg) and p.o. (10, 20 and 40 mg) administrations, 4-amino-6-methyoxy-1-phenyl-pyridazinium methyl sulfate (ameziniummetilsulfate, LU 1631, Regulton), in the following briefly called amezinium, a new antihypotensive agent, was studied by non-invasive methods for its cardiovascular action in comparison with norfenefrine (10 mg i.m. and 40 mg p.o.) and dihydroergotamine (1 mg i.m. and 4 mg p.o.) in a group of 33 volunteers. The action pattern of 10 mg amezinium i.v. consisted of a significant rise in arterial blood pressure (systolic 23%, diastolic 14%) with an increase in pulse pressure (38%) and a reflex fall in heart rate (9%). The total peripheral resistance was increased by 29%, with a moderate reduction of cardiac output (5%; n.s.) and an increase of the stroke volume (6%; n.s.). A clear positive inotropic effect was discernible by the significant reduction of heart rate, corrected preejection period (delta PEP; 13 ms), left ventricular ejection time (delta LVET; 8 ms; n.s.) and a decrease of the ratio PEP/LVET (-0.028). This pattern of action points to stimulation of vascular alpha- as well as cardiac beta 1-adrenoceptors and is in accordance with the findings from animal experiments as amezinium acts via endogenous noradrenaline. The reference substance norfenefrine exhibited purely alpha-sympathomimetic action, whereas dihydroergotamine presumably exerted venoconstrictive and central sympatholytic effects. The effects of amezinium after p.o. administration on the circulation were similar to those after i.v. administration, whereas the reference substances did not reveal any definite pharmacodynamic action when given p.o. Single administrations of the various p.o. doses of amezinium gave rise to a dose-dependent increase of the systolic blood pressure, persisting over the 180 min of the investigation period. From the dose-response relationships after parenteral and oral administration a relative enteral efficacy of 50-80% was established, which corresponds well with bioavailability data. The results show amezinium to have potent, long-lasting blood pressure increasing and positive inotropic actions in man after oral as well as parenteral administration.
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PMID:Haemodynamic effects of amezinium in man. 719 78