Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043352 (xerostomia)
 4,250 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Among the newer antihypertensive agents are the beta-blocking drugs, such as propranolol. These agents are useful as second-step drugs to be used if diuretic therapy alone is not effective. In mild to moderately severe hypertension, propranolol, in does of up to 480 mg/day in combination with a thiazide diuretic, has been found to be effective in over 80% of patients on long-term therapy. This degree of response is essentially similar to that noted with a combination of reserpine and a diuretic agent. Although some observers believe that propranolol produces many fewer side effects than the other step 2 drugs (reserpine and alpha-methyldopa), there are some patients who do experience restlessness, insomnia, and depression. Clonidine may be substituted for another step 2 drug, is of moderate potency, but may not be tolerated by a large number of patients because of the severe dry mouth and drowsiness that it produces. Prazosin appears to be a suitable substitute for hydralazine as an effective vasodialator if thiazides plus propranolol or thiazides plus reserpine or alpha-methyldopa are not effective. In some instances, it many be an acceptable second-step drug because of its alpha-adrenoreceptor-blocking properties. The angiotensin II competitive inhibitors or converting enzyme inhibitors may in the future have some place in the management of hypertension.
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PMID:Propranolol and newer antihypertensive drugs in the management of hypertension. 42 60

11 coronary patients, 8 with mild hypertension, were treated with clonidine, at a dose of 75 micrograms b.i.d. per os for a week. The effect of the drug on coronary heart disease was assessed by means of a symptom-limited multistage exercise test on the cycloergometer. Clonidine was effective in reducing the exercise-induced increases in blood pressure (by 15.5 +/- 6.1%), the double product (by 34.8 +/- 20.8%) and the electrocardiographic ischemic changes. In 2/4 patients, effort related ventricular extrasystoles were reduced by greater than 50% after clonidine. The drug worsened the anginal pain in 3 and relieved the pain in 3 patients. However, it reduced the exercise-induced ST-T segment downsloping in 7 patients. The tolerance was good, since only 3/11 patients reported slight dry mouth, sedation and pyrosis. In view of the electrocardiographic effect, further studies with clonidine on myocardial ischemia should be performed.
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PMID:The therapeutic value of clonidine in patients with coronary heart disease. 49 82

In a small number of studies and isolated case reports, intrathecally administered clonidine has been reported to relieve intractable cancer pain and to prolong spinal anesthesia induced by various local anesthetics. A double-blind placebo-controlled clinical trial was carried out in order to evaluate the effect of intrathecal clonidine on pain following cesarean section. Twenty patients who underwent elective cesarean section received, 45 min after general anesthesia, either 150 micrograms (n = 10) clonidine or saline (control group, n = 10) intrathecally. Pain scores were lower in clonidine- than saline-treated patients from 20 to 120 min after intrathecal injection, as measured by a visual pain linear analog scale (P less than 0.05). Pain relief, in terms of the first supplemental analgesic request by patients, lasted 414 +/- 128 min after intrathecal clonidine and 181 +/- 169 min (mean +/- SD) (P less than 0.01) after saline. Clonidine decreased systolic, diastolic, and mean arterial pressures compared to baseline values (P less than 0.05), but heart rate and central venous pressure were unaffected (difference not significant). Maximal reduction of systolic arterial pressure was 15 +/- 9%, of diastolic arterial pressure 22 +/- 12%, and of mean arterial pressure 18 +/- 12%. Clonidine did not affect arterial hemoglobin oxygen saturation or PaCO2. Patients in the clonidine group were significantly more sedated (P less than 0.05) and more frequently reported a dry mouth (P less than 0.01) compared to the normal saline group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intrathecal clonidine as a sole analgesic for pain relief after cesarean section. 164 46

The activity of MK-467, a new peripherally acting alpha 2-antagonist, was assessed in volunteers by a randomized, double-blind, crossover design. One hour after administration of either 15 mg or 30 mg MK-467 or placebo, 200 micrograms clonidine was given intravenously and observations were made for a further 8 hours. Clonidine reduced plasma norepinephrine levels to 79% +/- 7% of that of control 1 hour after infusion, an effect that was antagonized by low-dose MK-467 (p less than 0.05). Mean systolic blood pressure increased by 4 mm Hg in the first hour after the 30 mg dose of MK-467 (p less than 0.01), although there was no significant difference between the 3 study days in the maximal clonidine-induced decrease in systolic pressure, diastolic pressure, or heart rate. Clonidine induced a peak increase in mean blood glucose of 13%, which was antagonized by both doses of MK-467 (p less than 0.05). Plasma insulin was suppressed by clonidine from 72 +/- 14 to 47 +/- 7 IU.L-1, an effect antagonised by both doses of MK-467 (p less than 0.05 in each case). MK-467 had no effect on clonidine-induced increased drowsiness, xerostomia, or increase in growth hormone secretion, which is consistent with it being a peripherally acting specific alpha 2-antagonist. The small effect of MK-467 on clonidine-induced changes in plasma glucose and insulin suggests that peripheral alpha 2-adrenergic receptors play only a minor role in normal glucose homeostasis.
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PMID:Assessment of MK-467, a peripheral alpha 2-adrenergic receptor antagonist, with intravenous clonidine. 167 20

Five hundred and fifty-nine hypertensive outpatients with diastolic blood pressure between 95 and 110 mmHg participated in this double-blind, placebo-controlled, multicenter study. Eligible subjects were randomly allocated to receive either clonidine (75 micrograms twice daily) or a placebo. After 4 weeks, 'responders' to treatment (diastolic blood pressure reduced to less than or equal to 90 mmHg or by greater than or equal to 10 mmHg) were kept on monotherapy and checked at 4-weekly intervals for another 3 months. Non-responders were given 15 mg chlorthalidone and were also checked for a further 3 months. At the end of the first month, 54.2% of the subjects were responders to clonidine and 41.5% were responders to the placebo (P less than 0.05 for both groups). Of the remaining patients, 69.0% became responders to clonidine plus chlorthalidone, whereas only 34.7% were responders to placebo plus chlorthalidone (P less than 0.01 for both groups). Withdrawals from the study because of excessive diastolic blood pressure levels were about eight times less frequent among the subjects treated with clonidine, either alone or with chlorthalidone. Dry mouth was twice as frequent in the clonidine-treated patients, but there was no significant difference in the incidence of all side effects or the number of withdrawals from the study because of side effects between the two groups. We conclude that low-dose clonidine is effective in the treatment of mild or moderate hypertension. Clonidine-related side effects are still evident, but the overall tolerance profile for this reduced dosage of the drug appears to be favorable.
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PMID:Low-dose clonidine administration in the treatment of mild or moderate essential hypertension: results from a double-blind placebo-controlled study (Clobass). The Clobass Study Group. 216 88

Central and peripheral alpha-adrenoceptors play an important role in cardiovascular regulation, and selective alpha 1-adrenoceptor antagonists and alpha 2-adrenoceptor agonists have an established place in the therapy of hypertension. Prazosin is a selective alpha 1-antagonist that is both effective in lowering blood pressure and well tolerated. However, the more recently developed alpha 1-antagonists doxazosin and terazosin offer the advantage of having longer half-lives, allowing once daily administration. Clonidine is a centrally acting alpha 2-agonist whose clinical use has often been limited by the dose dependent side effects of dry mouth and sedation, and the belief that it should be given three times per day. However, recent studies have shown that it has substantial antihypertensive efficacy with minimal side effects at low doses, and that half-life is long enough to allow twice daily administration. An improved understanding of the pharmacodynamics and pharmacokinetics of drugs acting on alpha-adrenoceptors allows a more rational approach to their clinical application.
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PMID:Comparison of pharmacokinetics and pharmacodynamics of adrenoceptor agonists and antagonists as antihypertensive agents. 245 58

MK-912, a new alpha 2-adrenoceptor antagonist, was assessed in six volunteers by use of antagonism of the effects of intravenous clonidine as the main index of response. Subjects received single doses of either 0.2 or 2 mg of orally administered MK-912 or placebo in a randomized, double-blind, balanced, crossover design. Clonidine was infused intravenously over 10 minutes, 1 hour after dosing, and observations were made for 8 hours. The 2 mg dose of MK-912 significantly inhibited the clonidine-induced hypotension, bradycardia, xerostomia, and increase in plasma glucose concentrations that were observed during the placebo treatment period (p less than 0.05). The peak elevation in plasma growth hormone that was produced by clonidine on the day the placebo was given was inhibited an average of 87% by the 2 mg dose of MK-912 (p less than 0.01). Although there was a trend toward antagonism of clonidine by the 0.2 mg dose of MK-912, statistically significant differences from placebo were not consistently demonstrated for most parameters. However, a mean 59% inhibition of the clonidine-induced peak elevation of plasma growth hormone was observed (p less than 0.05). Oral MK-912 almost completely inhibits the effect of 200 micrograms of intravenous clonidine in human subjects, which is consistent with its role as a potent alpha 2-antagonist over the dose range of 0.2 to 2.0 mg.
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PMID:Assessment of MK-912, an alpha 2-adrenoceptor antagonist, with use of intravenous clonidine. 256 10

Sixteen of 22 elderly male patients (aged 60-74 years) who had previously taken only hydrochlorothiazide 50 mg completed a study evaluating the safety, efficacy, and tolerability of 12-20 weeks of transdermal clonidine (Catapres TTS) as monotherapy for mild hypertension. Thirteen of the sixteen patients (81%) responded to transdermal clonidine which was begun after 28 days of placebo. Five patients discontinued transdermal clonidine therapy because of intolerable skin irritation, and one because of daytime fatigue. Clonidine caused none of the metabolic effects we observed with hydrochlorothiazide: no change in serum potassium, uric acid, cholesterol, or triglyceride. Eleven of the 22 patients (50%) who began the study experienced a skin reaction under the transdermal clonidine patch. The incidence of dry mouth and fatigue in patients using transdermal clonidine was dose-related and similar to reports of dry mouth and fatigue in patients taking oral clonidine tablets. Rebound hypertension occurred in one patient upon withdrawal of transdermal clonidine. There was no effect of transdermal clonidine or hydrochlorothiazide on cognitive function or emotional state tested with three questionnaires. Overall, transdermal clonidine, in various doses, was as effective as hydrochlorothiazide in elderly male hypertensive patients. The effectiveness of both was inversely proportional to the level of untreated blood pressure. The high incidence of skin reactions limited prolonged use of transdermal clonidine in our patients.
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PMID:Transdermal clonidine compared with hydrochlorothiazide as monotherapy in elderly hypertensive males. 271 69

The clinical records of 25 ambulatory patients who received clonidine (Catapres-TTS) for periods of one to 19 months were reviewed to determine the effectiveness and long-term patient tolerance of this transdermal antihypertensive medication. In 11 patients with mild to moderate hypertension in whom Catapres-TTS was initiated as monotherapy or added to an oral diuretic, significant blood pressure reduction was observed during the initial four weeks of therapy. In 14 patients who had more severe hypertension and who were receiving multiple antihypertensive agents, Catapres-TTS did not result in significantly reduced blood pressure. Daily home blood pressure measurements in five patients showed no day-to-day variations in blood pressure during the seven days each patch was worn. Catapres-TTS was discontinued in 11 patients because of localized contact dermatitis (six patients), patient dissatisfaction (three patients), and physician's decision (two patients). In three patients, localized contact dermatitis developed only after continuous use for periods of four to 13 months. Other adverse effects such as drowsiness and dry mouth were less apparent than with comparable doses of oral clonidine, and did not necessitate discontinuation of therapy in any patient. Black patients appear to tolerate Catapres-TTS better than whites. Catapres-TTS appears to be effective in patients with mild to moderate hypertension and may be a useful alternative to oral clonidine in patients experiencing drowsiness or dry mouth with the oral preparation.
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PMID:Patient acceptance of transdermal clonidine. A retrospective review of 25 patients. 273 24

Clonidine is a centrally active antihypertensive agent effective in the treatment of mild, moderate and severe hypertension, alone or in combination with other drugs. Use of oral clonidine has often been limited by side effects which include dry mouth and drowsiness. Transdermal clonidine was therefore developed as an alternative to oral therapy. Ideally, a drug administered at a constant rate into the systemic circulation should attain steady-state concentrations with less peak-to-trough fluctuation than that associated with intermittent oral dosing. In theory, transdermal administration should thus minimise the adverse effects associated with peak plasma drug concentration, while avoiding the potential for decreased efficacy associated with trough levels. Clonidine has been incorporated into a small, pliable adhesive cutaneous delivery device designed to provide therapeutically effective doses of drug at a constant rate for at least 7 days. The transdermal therapeutic system is a laminate consisting of an external film impermeable to moisture and to the drug, a thin layer of active drug dispersed within a highly drug-permeable matrix, a membrane with a controlled intrinsic permeability regulating the rate of delivery of drug to the skin, and an adhesive coating that attaches the system to the skin surface. The permeation of drug through the skin occurs primarily by diffusion. Application of the clonidine transdermal system to both normotensive and hypertensive subjects has consistently reduced systolic and diastolic blood pressures. Maximum reduction in blood pressure occurs 2 to 3 days after initial application, and is maintained for at least 7 days or until the system is removed. The rate at which clonidine is presented to the skin surface is controlled by the microporous membrane: this rate is the same for all strengths of transdermal clonidine, the amount of clonidine released being proportional to its surface area. Thus, the daily dose is regulated by the area of skin covered. Typically, steady-state plasma concentrations are reached on the fourth day after initial transdermal system application. The lack of dose dependency in half-life and renal clearance estimates emphasise that the transdermal absorption of clonidine is linear. The plasma clonidine concentration produced by a particular transdermal dose varies considerably between individuals as a result of interindividual variation in renal clearance. For this reason, it is recommended that dosages be titrated up from the smallest system (3.5 cm2) until the desired pharmacological effect has been obtained.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Clinical pharmacokinetics of clonidine. 329 68


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