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

Angiotensin II receptor blockers (ARBs) represent a new class of effective and well tolerated orally active antihypertensive agents. Recent clinical trials have shown the added benefits of ARBs in hypertensive patients (reduction in left ventricular hypertrophy, improvement in diastolic function, decrease in ventricular arrhythmias, reduction in microalbuminuria, and improvement in renal function), and cardioprotective effect in patients with heart failure. Several large long-term studies are in progress to assess the beneficial effects of ARBs on cardiac hypertrophy, renal function, and cardiovascular and cerebrovascular morbidity and mortality in hypertensive patients with or without diabetes mellitus, and the value of these drugs in patients with heart disease and diabetic nephropathy. The ARBs specifically block the interaction of angiotensin II at the AT1 receptor, thereby relaxing smooth muscle, increasing salt and water excretion, reducing plasma volume, and decreasing cellular hypertrophy. These agents exert their blood pressure-lowering effect mainly by reducing peripheral vascular resistance usually without a rise in heart rate. Most of the commercially available ARBs control blood pressure for 24 h after once daily dosing. Sustained efficacy of blood pressure control, without any evidence of tachyphylaxis, has been demonstrated after long-term administration (3 years) of some of the ARBs. The efficacy of ARBs is similar to that of thiazide diuretics, beta-blockers, angiotensin-converting enzyme inhibitors or calcium channel blockers in patients with similar degree of hypertension. Higher daily doses, dietary salt restriction, and concomitant diuretic or ACE inhibitor administration amplify the antihypertensive effect of ARBs. The ARBs have a low incidence of adverse effects (headache, upper respiratory infection, back pain, muscle cramps, fatigue and dizziness), even in the elderly patients. After the approval of losartan, five other ARBs (candesartan cilexetil, eprosartan, irbesartan, telmisartan, and valsartan) and three combinations with hydrochlorothiazide (irbesartan, losartan and valsartan) have been approved as antihypertensive agents, and some 28 compounds are in various stages of development. The ARBs are non-peptide compounds with varied structures; some (candesartan, losartan, irbesartan, and valsartan) have a common tetrazolo-biphenyl structure. Except for irbesartan, all active ARBs have a carboxylic acid group. Candesartan cilexetil is a prodrug, while losartan has a metabolite (EXP3174) which is more active than the parent drug. No other metabolites of ARBs contribute significantly to the antihypertensive effect. The variation in the molecular structure of the ARBs results in differences in the binding affinity to the receptor and pharmacokinetic profiles. The differences observed in lipid solubility, absorption/distribution, plasma protein binding, bioavailability, biotransformation, plasma half-life, and systemic elimination influence the time of onset, duration of action, and efficacy of the ARBs. On the basis of the daily mg dose, the antihypertensive potency of the ARBs follows the sequence: candesartan cilexetil > telmisartan approximately = losartan > irbesartan approximately = valsartan > eprosartan. After oral administration, the ARBs are rapidly absorbed (time for peak plasma levels = 0.5-4 h) but they have a wide range of bioavailability (from a low of 13% for eprosartan to a high of 60-80% for irbesartan); food does not influence the bioavailability, except for valsartan (a reduction of 40-50%) and eprosartan (increase). A limited dose-peak plasma levels/areas under the plasma level-time curve proportionality is observed for some of the ARBs. Most of these drugs have high plasma protein binding (95-100%); irbesartan has the lowest binding among the group (90%). The steady-state volumes of distribution vary from a low of 9 L (candesartan) to a high of 500 L (telmisartan). (ABSTRACT TRUNCATE
 ...
PMID:Clinical pharmacokinetics of angiotensin II (AT1) receptor blockers in hypertension. 1085 85

Angiotensin II receptor blockers have shown widespread efficacy as antihypertensive medications. These agents bind selectively to angiotensin II type 1 (AT(1)) receptors, specifically blocking the renin-angiotensin system at the last step in its cascade. CS-866 is the most recently introduced drug in this class. This article presents integrated safety and efficacy data from 7 randomized, double-blind, placebo-controlled, parallel group studies in which once-daily CS-866 monotherapy was used in the treatment of patients with essential hypertension (sitting diastolic blood pressure > or =100 mm Hg and < or =115 mm Hg). Data from a total of 2,145 CS-866-treated patients were included in the efficacy analysis. Safety data were available from 2,540 CS-866-treated patients, with a cumulative exposure of 5,888 patient-months. The antihypertensive efficacy of the drug was assessed using both cuff blood pressure measurements and 24-hour ambulatory blood pressure monitoring. The data show that CS-866 is effective and safe for the treatment of hypertension. Dose-dependent reductions in both diastolic and systolic blood pressures occurred within 1 week of initiating treatment, and the response was almost maximal within 2 weeks. There was no difference in efficacy between younger (<65 years) and older (> or =65 years) groups of patients. Trough-to-peak ratios showed that CS-866 retains the majority of its peak effect 24 hours after treatment, and is therefore suitable for once-daily dosing. Dizziness was the only treatment-emergent adverse event with which CS-866 was associated.
 ...
PMID:Clinical studies of CS-866, the newest angiotensin II receptor antagonist. 1133 67

The ideal antihypertensive drug should be effective in reducing blood pressure, but have a low incidence of adverse effects. Angiotensin II receptor blockers, such as eprosartan, are as effective as ACE inhibitors in reducing blood pressure, but lack the main adverse effect of ACE inhibitors, namely cough. Eprosartan has been shown to be well tolerated with a placebo-like adverse-effect profile. When given as monotherapy it is effective in reducing blood pressure; however, some patients require additional blood pressure control, which may be provided by combination therapy. Indeed, the combination of eprosartan and the thiazide diuretic hydrochlorothiazide has been shown to be effective in further reducing blood pressure in patients not optimally responding to eprosartan monotherapy. This article reviews the safety and tolerability of eprosartan in combination with hydrochlorothiazide from 17 studies of 1899 patients with hypertension and normotensive volunteers. Of these studies, four were controlled with patients receiving a fixed-dose combination, six were long-term, open-label, and another four were controlled studies with hydrochlorothiazide being given to eprosartan non-responders. The other three studies included healthy subjects receiving the combination of eprosartan and hydrochlorothiazide. There was a high completion rate in all studies evaluated. Most of the patients receiving eprosartan 600mg in combination with hydrochlorothiazide 12.5mg daily completed the studies, which supports acceptance of this combination therapy by patients. The most frequently reported adverse events in these combination studies were headache, dizziness, myalgia, and upper respiratory tract infection in patients with hypertension. The majority of adverse events were mild to moderate in intensity, and were not considered to be related to study treatment. The adverse event that was more common in patients receiving combination therapy compared with those receiving monotherapy was dizziness. This adverse event may be due to hydrochlorothiazide as it has previously been observed in patients taking thiazide diuretics. In healthy volunteers, the most frequently reported adverse events were headache, dizziness, and upper respiratory tract infection. However, none of these adverse events were considered related to study medication. In summary, the combination of eprosartan/hydrochlorothiazide is well tolerated, both as short- and long-term therapy, with most adverse events occurring early. The most frequent adverse events were headache, dizziness, and upper respiratory infection, which would be expected based on the safety profile of each of the components. Therefore, the combination of eprosartan with hydrochlorothiazide can be effectively and safely used in patients not adequately responding to eprosartan monotherapy.
 ...
PMID:Safety and tolerability of eprosartan in combination with hydrochlorothiazide. 1211 44