Cerebrospinal fluid rhinorrhea during treatment with bromocriptine for prolactinoma.
In 27 young normotensive subjects forearm blood flow (FBF) was measured with venous occlusion plethysmography during local intra-arterial infusions of methacholine (MCh), evaluating EDV, and sodium nitroprusside (SNP), evaluating endothelium-independent vasodilatation (EIDV). The measurements of EDV and EIDV were undertaken at baseline conditions and repeated after 1 h of concomitant intra-arterial infusion of atenolol (n = 8, 1.2 mg/h), propranolol (n = 7, 1.2 mg/h), labetalol (n = 7, 16 mg/h) or saline (n = 5).
Labetalol, an alpha and beta receptor blocking agent, was evaluated in 11 patients with documented coronary artery disease and stable angina. The mean dose of labetalol was 1.5 (range 1 to 2) mg/kg. Cardiovascular effects began within 1 minute after injection and were maximal within 10 minutes. Mean arterial pressure decreased from 105 +/- 13 to 81 +/- 10 mm Hg (p less than 0.0001), heart rate from 70 +/- 10 to 66 +/- 7 beats/min (p less than 0.05) and the pressure-rate product from 10,322 +/- 2,344 to 7,171 +/- 1,650 (p less than 0.001). Cardiac output and pulmonary wedge pressure did not change significantly. Mean pulmonary arterial pressure decreased from 20 +/- 3 to 16 +/- 2 mm Hg (p less than 0.005). Systemic and pulmonary resistances also decreased significantly (p less than 0.0001 and p less than 0.01, respectively). Coronary sinus flow increased from 107 +/- 26 to 118 +/- 25 ml/min (p less than 0.01) and coronary vascular resistance decreased from 1.0 +/- 0.2 to 0.77 +/- 0.1 mm Hg/ml per min (p less than 0.001). Labetalol may be a useful adjunct in the treatment of angina not only because it diminishes myocardial oxygen requirements but also because it improves coronary hemodynamics. Thus, labetalol appears to have some advantage compared with the usual beta blocking agents with their potentially detrimental effects on coronary hemodynamics.
This review summarizes current and emerging pharmacotherapies for the treatment of tobacco dependence, including first- and second-line recommended agents. Medications with alternative primary indications that have been investigated as potential treatments for tobacco dependence are also discussed. Articles reviewed were obtained through searches of PubMed, Ovid MEDLINE, ClinicalTrials.gov and the Pharmaprojects database.
A study was carried out in 73 patients with mild or moderate hypertension to assess the effectiveness of treatment with labetalol. After a 2 to 4-week period on placebo, patients received 200 mg labetalol daily for 4 weeks, after which time dosage was doubled if the blood pressure was not satisfactorily controlled. Treatment was continued for a further 4 weeks and was followed by another period on placebo. Pre-treatment levels of 157/99 mmHg were significantly reduced after 2 weeks, and after 4 weeks the mean reduction was 14/8 mmHg. Half the patients had their dosage increased to 400 mg daily. At the end of the 8-week active treatment period, 80% were adequately controlled, the mean reduction in blood pressure being 22/12 mmHg compared with placebo values. Heart rate was significantly reduced from 78 to 69 beats per min during labetalol therapy. The reduction in blood pressure was similar whether or not patients had been previously treated or untreated, but heart rate was reduced more in the previously treated group. Four weeks after the end of labetalol therapy blood pressure and heart rate had increased but were less than during the initial placebo period and did not give rise to any severe problems.
Preeclampsia and eclampsia continue to be major causes of maternal death. Currently, approximately 18% of U.S. maternal deaths are attributed to hypertensive disorders and eclampsia, and several hundred women die from eclampsia and its complications every year. In the United States, preeclamptic women have received magnesium sulfate as a seizure prophylaxis agent for 3 decades, and this practice is becoming more widely accepted internationally. In addition to a recognized failure rate, there are financial, logistic, and safety concerns associated with the universal administration of magnesium sulfate. Many institutions in the developing world lack the necessary equipment and expertise to administer the medication, and many preeclamptic patients thus do not receive magnesium sulfate before their first seizure. As effective as it has been in reducing mortality from eclampsia, magnesium sulfate is also associated with appreciable morbidity and mortality from administration errors and magnesium toxicity. The availability of an easily administered, cheap, safe, and orally administered alternative to magnesium sulfate would be welcomed in the developing world and would provide an extremely useful alternative therapy to the current standard of care. Recent advances in the understanding of the pathophysiology of preeclampsia and eclampsia, primarily related to cerebral perfusion and blood flow, could allow us to reduce the seizure rate in treated preeclamptic women even further than what is currently reported. This article deals with the rationale behind the use of labetalol as an alternative to magnesium sulfate for the prevention of eclampsia.