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)

Rilmenidine is an oxazoline derivative with antihypertensive activity which was developed to enhance the dissociation between the hypotensive and adverse effect profile of centrally acting agents. Experimental studies have indicated that rilmenidine is selective for both alpha 2-adrenoceptors (v alpha 1) and newly discovered nonadrenergic imidazoline receptors in the brain and in the periphery. In experimental studies, rilmenidine differs from clonidine in that it is more selective for imidazoline receptors than for alpha 2-adrenoceptors; at equihypotensive doses, rilmenidine causes less bradycardia and reduction in cardiac output, less sedation, and little or no antinociceptive action compared to clonidine. The hypotensive effects of rilmenidine are antagonised by idazoxan and yohimbine, but idazoxan (imidazoline structure) is six times more potent than yohimbine (a selective alpha 2-antagonist). In isolated renal proximal tubule cells, where imidazoline binding has also been shown, rilmenidine inhibits reabsorption of sodium. Clinical studies comparing 1 mg rilmenidine with placebo demonstrated significant reductions in blood pressure (BP) (61% rilmenidine v 23% placebo normalized to 160/90 mm Hg). The reduction in BP was not associated with classical alpha 2 side effects such as dry mouth or daytime drowsiness. Compared with clonidine (0.15 to 0.3 mg), equihypotensive doses of rilmenidine (1 to 2 mg) induced two to three times less dry mouth, daytime drowsiness, and constipation; no orthostatic hypotension was reported. Methyldopa (0.5 to 1 mg) v rilmenidine (1 to 2 mg) indicated a comparable reduction of BP with significantly less weakness, drowsiness, orthostatic dizziness, and dry mouth on rilmenidine; there was no evidence of the "clonidine withdrawal syndrome" on drug withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Distinctive features of rilmenidine possibly related to its selectivity for imidazoline receptors. 135 Jul 32

The prevalence of hypertension in adult Nigerians is about 20% and hypertension remains a significant risk factor in cardiovascular morbidity and mortality. In Africans, hypertension carries a dismal prognosis, has a late clinical presentation and certain antihypertensives may be less effective. We therefore conducted a therapeutic audit in order to assess the initial cardiovascular risk profile of Nigerian patients as well as the safety and efficacy of different antihypertensive agents. A cross-sectional survey of 367 patients (M:F:2:1) modal age 25-44 years, mostly WHO II, enrolled in our clinic was undertaken. 56% had been on treatment for up to one year and 2% for longer than ten years. 12.5% had concomitant diabetes mellitus. Statistical analyses of drug efficacy were done by Spearman correlation and Analysis of Variance (ANOVA). The rank order of hypertensive efficacy was as follows: Thiazides (T) (r = 0.57, P less than 0.05), T + Methyldopa (M) (r = 0.91, P less than 0.001) T + M + Hydralazine (r = 0.92, P less than 0.001). Neither propranolol, nor frusemide showed significant overall efficacy. However, propranolol appeared efficacious in hypertensives with renal impairment. Postural dizziness was occasionally reported. Total mortality was 6% occurring mostly in the modal age group. Diabetic hypertensives had a 5 fold enhanced risk of a fatal outcome (X2 P less than 0.001). Our findings support a rational stepped care approach to pharmacotherapy of hypertension in black Africans, a cost-effectiveness analysis of common antihypertensives; it elucidates the associated adverse effects to patients, and draws attention to the lethality of concomitant hypertension and diabetes. Prospective large scale studies of the treatment of hypertension in Africans are required.
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PMID:A therapeutic audit in the management of hypertension in Nigerians. 260 27

A 33 year old man with a history of recurrent episodes of orthostatic dizziness since adolescence was noted to have a supine blood pressure of 200/120 mm Hg and a standing blood pressure of 90/60 mm Hg. Results of extensive laboratory studies for secondary hypertension were negative. Studies of the autonomic nervous system function revealed normal plasma catecholamines, cold pressor test and response to 4 minute 30% of maximal static handgrip contraction and an appropriate increase in heart rate on intravenous injection of atropine. In contrast, the heart rate response to phenylephrine and sodium nitroprusside infusion, carotid massage and graded neck suction with an airtight chamber was very abnormal, indicating marked dysfunction of the afferent limb of the arterial baroreceptor reflex system. Methyldopa decreased the supine hypertension and increased the standing blood pressure.
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PMID:Primary dysfunction of the afferent limb of the arterial baroreceptor reflex system in a patient with severe supine hypertension and orthostatic hypotension. 648 Oct 19

The current prescription patterns for essential hypertension and the efficacy, safety, tolerability and cost-effectiveness of the newer antihypertensive drugs were evaluated in Nigerian patients. The findings were compared with that of a previous study conducted in the same tertiary hospital 10 years earlier. A cross-sectional evaluation of blood pressure (BP) control in a hypertension clinic was undertaken among 150 Nigerian patients aged 61 +/- 12 years (55% females), with a duration of treatment on a particular drug class or combination of 9 +/- 3 months. The initial blood pressure was 176 +/- 20/108 +/- 11 mmHg and 22% of the patient had concurrent diabetes mellitus. Thiazide diuretics (D) alone or in combination remained the most commonly prescribed drugs in 56% of all patients. There were significant increases in the prescriptions of calcium channel blockers (CCBs) (51%), P < 0.0001, and ACE-inhibitors (ACEIs) (24%), P < 0.0001, but a slight reduction in the use of methyldopa, and fixed drug combinations (P < 0.01) compared to the previous study. The fall in systolic blood pressure on D (r = 0.65, P < 0.001) or CCB (r = 0.48, P < 0.02) was significantly correlated with the initial systolic blood pressure, but not age. More patients achieved normotension BP < 140/90 mmHg on CCB monotherapy (71%), than D monotherapy (56%). Combination therapy with ACEIs + D or methyldopa+thiazides normalized BP in 63 and 68%, respectively. Pulse pressure, a surrogate marker for cardiovascular complications and mortality in essential hypertension, was significantly reduced (P < 0.01) equally by all treatments, with 95% confidence intervals ranging from -28 to -1 mmHg. However, hypertensive-diabetic (HT-DM) patients (n = 33) exhibited no significant change in pulse pressure in response to treatment. Adverse drug reactions that occurred in 11% were impotence or postural dizziness with D, headache and pitting oedema with CCB, and dry cough with ACEI. Pharmaco-economic comparison of the drug classes revealed that for every US dollar (dollar) spent per month, the percentage of treated patients attaining normotension was 18.6 for D, 4.73 for CCB, 3.5 for ACEI + D and 13.6 for methyldopa + thiazides. A combination of ACEI + CCB or D was the preferred treatment for hypertensive-diabetic Nigerians, but only 24% attained a BP < 130/85 mmHg. These results demonstrate a shift in trend to a more rational and efficacious treatment of hypertension over a 10 year period. This may be associated, at least in part, with the intensive and continuous education of the prescribers in rational drug use and the introduction of a hospital formulary. Methyldopa is still a highly efficacious and cost-effective drug in this population. Black HT-DM Africans still constitute a subgroup who not only require more and costlier antihypertensive drugs, but whose BP control is suboptimal, and exhibit a poor therapeutic response to other risk factors (pulse pressure) that constitute a continuing risk for cardiovascular mortality.
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PMID:Shifting trends in the pharmacologic treatment of hypertension in a Nigerian tertiary hospital: a real-world evaluation of the efficacy, safety, rationality and pharmaco-economics of old and newer antihypertensive drugs. 1271 73