Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ketanserin, a selective S2-serotoninergic antagonist with an additional alpha 1-receptor-blocking effect and a central component of action, represents a new type of antihypertensive drug. It decreases blood pressure by reducing total peripheral resistance. Cardiac output and heart rate remain practically unaltered. The antihypertensive effect of 2 x 20 to 2 x 40 mg/day corresponds to that of therapeutic doses of metoprolol, nifedipine, hydrochlorothiazide or captopril. The main subjective side effects are somnolence, dizziness and dryness of the mouth. No serious metabolic side effects have been observed. Ketanserin can lead to a prolongation of the QTc interval and therefore should not be given to patients with preexisting QTc prolongation, atrioventricular or sinoauricular block of higher degree or with severe bradycardia (less than 50/min). If a diuretic is to be prescribed simultaneously, it must contain a potassium-sparing component. Since its antihypertensive effect is more pronounced in older age, ketanserin should preferentially be given to patients over 60 years of age.
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PMID:Clinical aspects during therapy with the serotonin antagonist ketanserin. 198 24

Ketanserin is a 5-HT2 receptor antagonist without partial agonist properties which also possesses weak alpha 1-adrenoceptor antagonistic activity, which may explain its antihypertensive mechanism of action in patients with essential hypertension. It also inhibits the effects of serotonin on platelets in cardiovascular disease, inhibits vasoconstriction caused by the amine, and when administered intravenously improves some haemorheological indices in patients with ischaemic diseases. The antihypertensive effect of oral ketanserin 40 mg twice daily is comparable with that of total daily doses of metoprolol 200 mg, propranolol 160 mg, captopril 100 mg, enalapril 20 mg, hydrochlorothiazide 50 mg, or alpha-methyldopa 1000 mg and is achieved without adverse effect on plasma lipoproteins or carbohydrate metabolism in patients with concomitant diabetes mellitus. Evidence from prospective studies suggests a greater antihypertensive efficacy in the elderly than in younger patients. In patients with intermittent claudication, results have been inconsistent in small studies, while a large study showed no improvement in pain-free walking distance but fewer amputations compared to placebo. In Raynaud's phenomenon symptomatic improvement relative to placebo was achieved in larger trials. Its role in preventing atherosclerotic complications requires further investigation. Ketanserin is reasonably well tolerated, the frequency of adverse effects being comparable with that of other antihypertensive drugs in controlled trials. Dizziness, tiredness, oedema, dry mouth and weight gain are the most commonly reported effects. Ketanserin prolongs QT interval in a dose-related manner, and when given in certain predisposing circumstances ventricular arrhythmias and syncope may occur. Administered intravenously, ketanserin 10mg followed by an infusion of 2 to 4 mg/h controls moderate to severe pre- and postoperative hypertension in most patients, acting as a balanced vasodilator, lowering cardiac pre- and afterload. Although the arrhythmogenic potential of ketanserin in patients receiving potassium-depleting diuretics requires suitable precautions, it appears that its antihypertensive activity is suited to the elderly provided plasma potassium concentrations are normal at the start of treatment and are maintained within the normal range.
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PMID:Ketanserin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in hypertension and peripheral vascular disease. 207 1

Ketanserin, the specific S2 serotonin antagonist, is undergoing evaluation for the therapy of hypertension of all degrees of severity. We studied 20 patients with severe hypertension [diastolic blood pressure (DBP) greater than 120 mm Hg after 40 min of supine rest]. In the first dose-ranging study on eight patients, multiple i.v. injections of 5 mg ketanserin were administered every 4 min (mean 38 mg). Only 4 patients responded adequately (DBP less than 100 mm Hg), 2 responded partially, and 2 did not respond to ketanserin. The major adverse effect of ketanserin, found in all patients, was severe dose-dependent sleepiness. A second double-blind crossover study with ketanserin and placebo (12 patients) assessed neural side effects. The supine DBP dropped from a mean of 134 +/- 4 mm Hg to 112 +/- 4 mm Hg 20 min after ketanserin when the sedation score rose from 0 to 1.2 +/- 0.3 (range 1-3) and the dizziness score from 0.1 +/- 0.1 to 1.4 +/- 0.3 (range 1-3; both p less than 0.01 vs. 1-2 min after ketanserin). Only 7 of 12 patients responded adequately to ketanserin. Twelve of the 20 patients were subsequently given nifedipine 10 mg sublingually; the DBP fell from a mean of 128 +/- 3 mm Hg to 101 +/- 4 mm Hg (p less than 0.001) after 40 min without side effects. Ketanserin does not appear to be a suitable agent for the acute therapy of severe hypertension because of: the imperfect and short-lived blood pressure control; the variability of the hypotensive effect; and sleepiness and dizziness as significant side effects.
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PMID:Effects of intravenous ketanserin on severely hypertensive patients with double-blind crossover assessment of central side-effects. 243 87

The role of serotonin in the pathogenesis of hypertension is interesting, and its investigation is much in vogue at present. This study compared the hypotensive effect of ketanserin, a specific 5-hydroxytryptamine receptor antagonist, with metoprolol in essential hypertension. On a double-blind basis, one treatment group (19 patients on ketanserin) was compared with another (21 patients on metoprolol). There was a significant reduction in diastolic blood pressure with both ketanserin and metoprolol (P less than 0,001). Side-effects were insignificant. One patient on metoprolol and 2 on ketanserin complained of dizziness. The dose of ketanserin was 40 mg twice a day and that of metoprolol 100 mg twice a day. Ketanserin does not appear to cause abnormal haematological values or biochemical adverse effects. It can be given to hypertensive patients with cardiac failure or bronchial asthma without adverse effects and may improve the peripheral vascular status of a hypertensive patient.
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PMID:A comparative study of ketanserin and metoprolol in essential hypertension. 293 40

Aggregating platelets release serotonin, which induces contraction of most vascular smooth muscle by activation of S2-serotoninergic receptors. Serotonin released in the circulation may contribute to the increase in peripheral resistance of hypertension as the responsiveness of blood vessels from hypertensive animals and humans to the vasoconstrictor action of the monoamine is augmented. The data obtained with the new antihypertensive agent ketanserin may favor that interpretation. Ketanserin is a selective S2-serotoninergic antagonist with additional alpha 1-adrenergic blocking properties. In humans, it has a terminal half-life of 12 to 25 hours and is eliminated predominantly by the liver. The hemodynamic profile of ketanserin is that of a vasodilator drug with actions on both resistance and capacitance vessels. On short-term intravenous administration, it lowers blood pressure in hypertensive patients with minimal reflex changes in cardiovascular function. When given orally long term to hypertensive patients, ketanserin causes a sustained reduction in arterial blood pressure, comparable to that obtained with either beta-adrenergic blockers or diuretics. Several studies have shown a greater efficacy in older (greater than 60 years of age) than in younger patients independent of starting pressure. Side effects mainly consist of dizziness, somnolence, and dry mouth, but they are usually not severe. The mechanism underlying the antihypertensive effect of ketanserin is unclear. It cannot be attributed to either S2-serotoninergic or alpha 1-adrenergic blockade alone, but an interaction between the two effects appears to be required.
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PMID:Serotoninergic mechanisms in hypertension. Focus on the effects of ketanserin. 327 10

Ketanserin was used in a randomized double-blind trial in 15 patients with Raynaud's phenomenon in progressive systemic sclerosis (PSS). Its effect on Raynaud's phenomenon was evaluated by IR-radiometry, Doppler ultrasound, nailfold capillaroscopy, frequency of finger ulcerations and patient complaints before and after a 3-month course of treatment with oral ketanserin in the dosage of 60 mg daily in the first month and 120 mg in the second and third months. Of the 8 patients treated with ketanserin, 5 showed improvement. In the other 2 patients with progression of skin sclerosis and multiorgan involvement, the peripheral vascular disorder was unchanged. Ketanserin treatment was discontinued in one patient owing to dizziness and anxiety. In one patient ketanserin was reduced to 60 mg daily because of fluid retention. There were no other adverse effects. In 7 control patients on placebo there was no significant improvement in Raynaud's phenomenon. Ketanserin, a selective, specific and pure antagonist of 5-hydroxytryptamine (serotonin) appears to be an effective agent in the treatment of Raynaud's phenomenon and digital ischaemic ulcers in PSS. Moreover, ketanserin could contribute to the understanding of the role of 5-hydroxytryptamine in PSS pathogenesis.
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PMID:Effect of ketanserin on Raynaud's phenomenon in progressive systemic sclerosis: a double-blind trial. 391 37