Hypotension with diuretics

When either drug is administered with diuretics and other hypotensives, an increased hypotensive effect may occur. When labetalol is administered with cimetidine, the effects of labetalol are increased. Halothane increases the effects of labetalol. When carvedilol is administered with the antidiabetic drugs, there is an increased effectiveness of the antidiabetic drugs. There is an increased effectiveness of clonidine when carvedilol is administered with clonidine There is an increased serum level of digoxin when digoxin is administered with carvedilol. 

The hypotensive effects of most antihypertensive dru are increased when administered with diuretics and other antihypertensives. Many dnigp can interact with the antihypertensive drugs and decrease their effectiveness (eg, antidepressants, monoamine oxidase inhibitors, antihistamines, and sympathomimetic bronchodilators). When the ACE inhibitors are administered with the NSAIDs, their antihypertensive effect may be decreased. Absorption of the ACE inhibitors may be decreased when administered with the antacids. Administration of potassium-sparing diuretics or potassium supplements concurrently with the ACE inhibitors may cause hyperkalemia. When the angiotensin II receptor agonists are administered with... 

Also, as with diuretics, cardiac output is gradually restored, yet the hypotensive effect remains. Labetalol, a unique 8-adrenoblocker best suited to lower blood pressure, combines nonselective 8-adrenergic blocking action on both p - and jSj-receptors with simultaneous blockage of tti-receptors. 

Hypotension/Votume- or salt-depleted patients In patients who are intravascularly volume-depleted (eg, those treated with diuretics), symptomatic hypotension may occur. Correct these conditions prior to administration. 

Hypotension, in particular in combination with diuretics, is a well-known adverse reaction to ACE-inhibitors when used in patients with heart failure. Dry cough, possibly mediated by the accumulation of bradykinin, is also a well-known side-effect in 5-15% of the patients treated with an ACE-inhibitor. Impaired renal function may be worsened by ACE-inhibitors. Allergic reactions, sometimes rather intense, may be observed occasionally. In rare cases angioneurotic edema has been described. ACE inhibitors should be avoided in women who are likely... 

Although less of a problem than with phenoxybenza-mine or phentolamine, symptoms of postural hypotension, such as dizziness and light-headedness, are the most commonly reported side effects associated with prazosin therapy. These effects occur most frequently during initial treatment and when the dosage is sharply increased. Postural hypotension seems to be more pronounced during Na+ dehciency, as may occur in patients on a low-salt diet or being treated with diuretics, (3-blockers, or both. 

Yarrow possesses diaphoretic, antipyretic, hypotensive, astringent, diuretic, and urinary antiseptic properties. Traditionally, it has been used for fevers, common colds, essential hypertension, amenorrhea, dysentery, diarrhea, and specifically for thrombotic conditions with hypertension, including cerebral and coronary thromboses. 

Interactions. Hyperkalaemia can result from use with potassium-sparing diuretics. Renal clearance of lithium is reduced and toxic concentrations of plasma lithium may follow. Severe hypotension can occur with diuretics (above), and with chlorpro-mazine, and possibly other phenothiazines. 

Orthostatic hypotension, although often loosely referred to in older literature (SED-10, 370) (159), is in fact only likely to become a problem in very old subjects, aged 90 years or more, even if a potent loop diuretic is used this was the clear conclusion of a good prospective study published in 1978 (159). In 843 independent hving men and women aged 60-87 years, postural fall in systolic blood pressure was not related to treatment with diuretics, after correction for initial blood pressure (160). At currently recommended doses, older subjects do not generally experience particular problems from hjrpokalemia and do not appear to be at special risk of cardiac dysrhythmias in the face of diuretic-induced hjrpokalemia (SEDA-15, 218). 

A prescription is received by the pharmacy for captopril (an ACE inhibitor) 12.5 mg bd and bendroflumethiazide (a diuretic) 2.5 mg om. The pharmacist notices that Appendix 1 of the British National Formulary states that there is an enhanced hypotensive effect when ACE inhibitors are administered with diuretics. What should the pharmacist do ... 

Older patients with isolated systolic hypertension are often at risk for orthostatic hypotension when drug therapy is started. This is particularly prevalent with diuretics, ACE inhibitors, and ARBs. Although overall treatment should be the same, initial doses should be very low and dose titrations gradual to minimize risk of orthostatic hypotension. 

Cautions Autoimmune disease (methyldopa) Orthostatic hypotension Allergy, bradyarrhythmias, coronary spasm, PVD Diabetes mellitus, digitalis toxicity, gout, hyperlipidemias Renal insufficiency, autoimmune diseases, drug interactions with diuretics, digoxin, Li Guanethidine asthma, GI ulcers, renal dysfunction Potent vasodilators > major compensatory fluid retention and cardiac stimulation... 

Phenothiazine derivatives cause postural or orthostatic hypotension. This may be more pronounced in patients with reduced vascular volume resulting from acute hemorrhage or dehydration, and when used with diuretic agents. Hypotension is more frequent with phenothiazine derivatives having either an aliphatic substitution on NIO (e.g., chlorpromazine) or a piperidine substitution on NIO (e.g., mesoridazine or thioridazine). It occurs less frequently with compounds containing a piperazine substitution (e.g., trifluoperazine). The hypotension is due to direct vasodilation and an alpha-adrenergic-receptor-blocking effect. The pressor effects of epinephrine can be reduced, blocked, or reversed by appropriate doses of chlorpromazine. 

The case history suggests that the syncope (fainting) is associated with diuretic use. Complications of diuretics that can result in syncope include both postural hypotension (which this patient exhibits) due to excessive reduction of blood volume and arrhythmias due to excessive potassium loss. Potassium wasting is more common with thiazides (because of their long duration of action), but these drugs rarely cause reduction of blood volume sufficient to result in orthostatic hypotension. The answer is (C). 

V 1 1 IV. 6 hr half-life, partially metabolized in liver, low plasma protein binding. Hypersensitivity to amrinone. Amrinone increases diuresis in patients on diuretics. Digitalis inotropy and risk of toxicity increased (amrinone causes hypokalemia). Excessive hypotension with disopyramide. If cellular supplies of cAMP are depleted, amrinone will not be effective. Capable of increasing myocardial contraction even in the presence of p-adrenergic antagonists. 

D X V 1 1 PO. Absorbed moderately well, 95% protein bound, extensively metabolized, 2.5 hr half-life. None identified. Increased risk of hypotension with beta blockers. Available in fixed dose combination with a thiazide diuretic. 

Increased antihypertensive and hypotensive effects with diuretics, sympathetic blockers. Inaeased serum potassium with potassium-sparing diuretics. Decreased antihypertensive effects with indomethacin. 

When minoxidil is administered with diuretics or other hypotensive drugs, the hypotensive effect of minoxidil increases, and concurrent use may cause profound orthostatic hypotensive effects. 

A. The hypotensive effect is potentiated by concomitant therapy with diuretics or beta-adrenergic blockers. 

A few patients taking some antihypertensives feel dizzy or begin to blank out or faint if they stand up quiekly or after exereise. This orthostatie and exertional hypotension may be exaggerated in some patients shortly after drinking alcohol, possibly beeause it ean lower the eardiae output (noted in patients with various types of heart disease ). For other reports of postural hypotension with alcohol, see alpha bloekers , (p.42), and ealeium channel blockers , (p.57). Some manufacturers of antihypertensives e.g. ACE inhibitors and thiazide diuretics" warn that acute alcohol intake may enhance the hypotensive effects, particularly at the start of treatment, and this could apply to any antihypertensive. Patients just beginning antihypertensive treatment should be warned. 

The manufacturer of indoramin states that concurrent use with diuretics may enhance their hypotensive action, and that titration of the dose of the diuretic may be needed. ... 

Sulindac does not appear to reduce either the hypotensive or diuretic effects of hydrochlorothiazide, and may even slightly enhance the antihypertensive effects. Another study found that sulindac did not alter the antihypertensive eflicacy of hydrochlorothiazide/amiloride given with beta blockers. Similarly, sulindac 200 mg twice daily for one month did not alter the antihypertensive effect of the combinations of hydrochlorothiazide 25 mg daily with fosinopril 10 to 40 mg daily, or lisinopril 10 to 40 mg daily. ... 

Zani, E, G. Massimo, S. Benvenuti, et al. 1991. Studies on the geno-toxic properties of essential oils with Bacillus subtilis rec-assay and Salmonella / microsome reversion assay. Planta Med. 57(3) 237-241. Zeggwagh, N.A., J.B. Michel, M. Eddouks, and A. Pereira. 2007. Acute hypotensive and diuretic activities of Chamaemelum nohile aqueous extract in normal rats. Am. J. Pharmacol. Toxicol. 2(3) 140-145. 

Glonidine. Clonidine decreases blood pressure, heart rate, cardiac output, stroke volume, and total peripheral resistance. It activates central a2 adrenoceptors ia the brainstem vasomotor center and produces a prolonged hypotensive response. Clonidine, most efficaciously used concomitantly with a diuretic in long-term treatment, decreases renin and aldosterone secretion. 

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