Antihypertensive agents adverse effects

The most common adverse effect seen with ESA is increased blood pressure, which can occur in up to 23% of patients.31 Antihypertensive agents may be required to control blood pressure in patients receiving ESAs. Caution should be used when initiating an ESA in patients with very high blood pressures (greater than 180/100 mm Hg). If blood pressures are refractory to antihypertensive agents, ESAs may need to be withheld. 

Dopamine antagonist activity is the hallmark of classical neuroleptics. The antihypertensive agents, reserpine (obsolete) and a-methyldopa, deplete neuronal stores of the amine. A common adverse effect of dopamine antagonists or depletors is parkinsonism. 

Minoxidil may produce serious adverse effects. It can cause pericardial effusion, occasionally progressing to tamponade it can exacerbate angina pectoris. Reserve for hypertensive patients who do not respond adequately to maximum therapeutic doses of a diuretic and 2 other antihypertensive agents. 

Altered homeostasis in older persons can lead to important and common adverse drug effects the less robust homeostatic milieu may be stressed by drugs, causing adverse effects. Examples include orthostatic hypotension due to antihypertensives and other agents that cause a-adrenergic blockade (e.g. terazosin, doxazosin, tricyclic antidepressants and phenothiazines) in those with barorecep-tor dysfunction. Diuretics can cause hyponatraemia or hypokalaemia in older patients, whereas ACE inhibitors and NSAIDs can cause hyperkalaemia. 

Other medications, which will not be discussed in the following chapters, have psychotropic actions that are considered to be side effects or adverse effects. Thus, some antihistamines (Le. products used to counteract allergic reactions) induce fatigue and drowsiness, and the same applies to some myorelaxants. Older antihypertensives (Le. agents reducing blood pressure) such as alpha-methyldopa (Aldomet ) or clonidine (Catapres 1) can cause fatigue and depression. 

In alleviating symptoms, drugs may also induce adverse effects, which may or may not be acceptable to patients. For example, numerous agents with anticholinergic properties cause dry mouth, which is easily correctable and hence is acceptable to patients. Conversely, some antihypertensive medications cause impotence in male patients, which they may find unacceptable, and this side effect may thus lead to lack of compliance with the prescribed medication. 

Bumetanide, piretanide and ethacrynic acid are similar to frusemide. Torasemide is also similar, but has also been demonstrated to be an effective antihypertensive agent at lower (non-natriuretic) doses (2.5-5 mg/d) than those used for oedema (5-40 mg). Ethacrynic acid is less widely used as it is more prone to cause adverse effects, especially nausea and deafness. 

Salt and fluid retention is an adverse effect of indometacin, although it is less important than with the pyrazolone derivatives. Indometacin can antagonize antihypertensive agents, including beta-adrenoceptor antagonists (19,20). The effect on blood pressure in normotensive patients has not been adequately studied. 

The documentation of adverse effects is still fragmentary. Tizanidine seems to be a relatively well tolerated and useful antispastic agent. The most frequently reported adverse effects include drowsiness, dry mouth, and muscle weakness (3). Occasionally, hypotension can occur it is usually mild (4,5) but can be more severe in patients taking antihypertensive drugs (6-8), in whom tizanidine should be used with great caution. A small fall in heart rate has also been reported (9). 

Effective antihypertensive therapy should include agents that do not adversely affect carbohydrate metabolic abnormalities. Commonly used antihypertensive agents, such as thiazide, thiazide-like diuretics and /3-blockers, are associated with glucose intolerance and increased insulin resistance (Sowers, 1991). In contrast, calcium antagonists and peripheral a-blockers (such as prazosin and terazosin) do not adversely affect glucose tolerance or insulin sensitivity. 

Patients should be monitored routinely for adverse drug effects. The most common side effects that attend each class of antihypertensive agents are discussed in the treatment section of this chapter, and laboratory parameters for primary agents are listed in Table 13-11. These side effects typically should occur 2 to 4 weeks after starting a new agent or increasing the dose, and laboratory tests should be... 

Lakshman MR, Reda DJ, Materson BJ, et al. Diuretics and beta-blockers do not have adverse effects at 1 year on plasma lipid and hpoprotein profiles in men with hypertension. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents. Arch Intern Med 1999 159 551-558. 

Methyldopa (Aldomet) is a centrally acting antihypertensive agent. It is a prodrug that exerts its antihypertensive action via an active metabolite. Although used frequently as an antihypertensive agent in the past, methyldopa s significant adverse effects limit its current use in the United States to treatment of hypertension in pregnancy, where it has a record for safety. 

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