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)

Classical centrally acting antihypertensive agents lower blood pressure by reducing excessive sympathetic tone; however, their clinical use is limited by an adverse effect profile resulting from alpha2-adrenoceptor agonism. Moxonidine is a new centrally acting agent showing selective agonism of imidazoline I1 receptors, but very little alpha2-adrenoceptor agonism. The safety and tolerability of moxonidine was reviewed over an 8-year period (1989 to 1997), including 74 clinical trials and an estimated 370000 patient-years of exposure. Dry mouth and somnolence were the most frequently reported adverse events, followed by headache and dizziness. In phase II to IV controlled studies in patients with hypertension (n = 1460), the incidence of dry mouth was 8 to 9%, somnolence 5 to 8% and headache 6%, as recorded by spontaneous reporting; the percentage of patients discontinuing treatment because of adverse events did not exceed 4%. Subgroup analyses revealed no differences in adverse events related to age or gender. Moxonidine did not exacerbate concomitant conditions such as diabetes mellitus or chronic obstructive pulmonary disease, or interact pharmacokinetically with concurrent medications such as hydrochlorothiazide, digoxin and glibenclamide (glyburide). Coadministration of moxonidine with lorazepam resulted in small additional impairments in tasks requiring attention. A similar distribution of adverse events was observed in uncontrolled studies (n = 1058). The incidence and severity of dry mouth and somnolence were found to decrease with increasing exposure to moxonidine over a period of up to 2 years. Serious adverse events were rare in all trials and could not be attributed to administration of moxonidine. Post-marketing surveillance of the adverse effect profile of moxonidine detected 2 additional adverse effects: nausea and allergic skin reactions. The safety profile of moxonidine, combined with proven antihypertensive efficacy, suggests that it may have an important role to play in the management of mild-to-moderate hypertension.
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PMID:Safety and tolerability of moxonidine in the treatment of hypertension. 974 66

Centrally acting antihypertensive drugs, or sympatholytics, (reserpine, methyldopa and clonidine) have a long history of efficacy but are now little used in most countries. One of the most important reasons for this is relatively poor tolerability compared to many newer agents. In the case of clonidine there is also the potential danger of rebound hypertension. The most prominent adverse effects have been dry mouth, sedation, dizziness and oedema. These reactions, especially the first two, are thought to be associated with activation of central nervous system and salivary gland alpha2-adrenergic receptors. In the last 15 years it has become possible to produce drugs with selective agonist effect on another class of brainstem receptors, the imidazoline I1-receptors, which appear to have modulate sympathetic activity and blood pressure without affecting alertness or salivary flow: however, they still have some action on alpha2-receptors. Moxonidine and rilmenidine are moderately selective imidazoline agonists which have been in clinical use for several years in many European countries. Trial evidence and postmarketing surveillance indicate that moxonidine may cause dry mouth or sedation in a minority (<10%) of patients, significantly less than with the older drugs. There is no significant incidence of oedema and unexpected or idiosyncratic adverse effects are extremely rare. Moxonidine may improve aspects of glucose and lipid metabolism. In conclusion, moxonidine is a safe as well as an effective antihypertensive, with considerably improved patient tolerability compared to the older sympatholytics.
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PMID:Moxonidine: a review of safety and tolerability after seven years of clinical experience. 1048 97