Neuropsychiatric manifestations of cardiovascular drug therapy

Commonly used cardiovascular medications have neuropsychiatric effects, which can be either harmful or of therapeutic benefit to patients. For example, sedation and mental depression have been described with centrally acting antihypertensive drugs and beta-adrenergic drugs, and are related to their antiadrenergic actions. At the same time, because of these antiadrenergic actions, agents like clonidine have been used for treatment of opiate, alcohol, and nicotine withdrawal, and beta blockers have been used to treat performance anxiety and psychocardiac disorders. Antiarrhythmic drugs have been associated with delirium, and digitalis toxicity can be associated with hallucinations, mania, euphoria, and depression. Antiarrhythmic agents such as verapamil are used as adjunctive treatment for managing patients with bipolar disorders. Because neuropsychiatric disorders can be seen in patients with cardiovascular disease, it is important for the clinician to be aware of the possible relationships between these disorders and concurrent cardiovascular drug therapy. The neuropsychiatric actions of antihypertensive, antiarrhythmic, and hypolipidemic agents are discussed in this article.

Raloxifene, a new selective estrogen receptor modulator

There is evidence from observational studies that estrogen replacement therapy in postmenopausal women can reduce the rates of morbidity and mortality of atherosclerotic heart disease. The mechanism of this cardiovascular protective effect is not yet established, but favorable actions of hormone therapy on plasma lipids and vascular endothelial function have been proposed. Estrogens can also increase the risk of breast and uterine carcinoma. The new selective estrogen receptor modulator (SERM) raloxifene appears to have benefits similar to estrogen on plasma lipids and osteoporosis, but it does not affect the rate of uterine carcinoma as does tamoxifen and estrogen. Animal studies suggest an anti-atherosclerotic action of raloxifene, but this needs to be confirmed in long-term human studies.

Antiplatelet therapy: glycoprotein IIb/IIIa receptor antagonists

The glycoprotein IIb/IIIa antagonists are potent drugs that inhibit platelet aggregation. They are formulated as monoclonal antibodies and synthetic peptides for intravenous use in patients undergoing high-risk angioplasty procedures and in patients with unstable coronary syndromes. Orally active agents are now being evaluated in clinical trials.

Testosterone and other anabolic steroids as cardiovascular drugs

There has been much interest in the effect of sex hormones on cardiovascular risk factors and as a therapeutic modality in both men and women. In this article, testosterone is considered as a possible therapy for cardiovascular disease. It has been shown that the level of serum testosterone decreases in men as they age. Healthy men with low testosterone levels have increased cardiovascular risk factors, including high fasting and 2-hour plasma glucose, serum triglycerides, total cholesterol and low-density lipoprotein (LDL) cholesterol, and apo A-I lipoprotein. Injections of testosterone to raise the levels to midnormal range have been shown to decrease total cholesterol and LDL cholesterol, while increasing high-density lipoprotein (HDL) cholesterol. Testosterone affects the clotting system by increasing thromboxane A (2) receptor activity and platelet aggregability. Testosterone has also been shown to augment the fibrinolytic system and antithrombin III activity. In men, testosterone has been shown to have antianginal effects, and endogenous levels have an inverse relationship to systolic blood pressure. Testosterone can be given in oral, injectable, pellet, and transdermal patch forms. There may be a role in administering testosterone to return men to normal physiologic range who have low serum levels. This treatment increases the risk of prostatic cancer, benign prostatism, erythrocytosis, and edema. No long-term studies of the effects of long-term testosterone replacement have been undertaken, so it is difficult to recommend this treatment as yet, but it is being considered as a therapy for augmenting skeletal muscle strength in patients with congestive heart failure.

Comparison of telmisartan with lisinopril in patients with mild-to-moderate hypertension

In this study, telmisartan, a new angiotensin AT ( 1 ) receptor antagonist given as monotherapy and in combination with hydrochlorothiazide (HCTZ), was compared with lisinopril as monotherapy and in combination with HCTZ. This 52-week, randomized, multicenter, double-blind, double-dummy, parallel-group, dose-titration study of 578 patients with mild-to-moderate essential hypertension (mean diastolic blood pressure [DBP], >/=95 mm Hg), compared the efficacy and safety of telmisartan (n = 385) with lisinopril (n = 193). Dosage could be increased for both telmisartan (40 --> 80 --> 160 mg) and lisinopril (10 --> 20 --> 40 mg) at each of the first 2 monthly visits if DBP control (<90 mm Hg) had not been established. Once DBP control was established, patients entered the 48-week maintenance period. During this period, the dose of the study drug was fixed, although open-label HCTZ at 12.5 mg or 25 mg was added, when needed, to regain DBP control. At the end of the titration period, DBP control was achieved on monotherapy by 67% and 63% of the telmisartan and lisinopril patients, respectively. At the end of the maintenance period, supine DBP was controlled in 83% and 87% of the telmisartan and lisinopril patients, respectively, with systolic blood pressure over DBP reductions of 23.8/16.6 mm Hg for telmisartan and 19.9/15.6 mm Hg for lisinopril. Treatment-related side effects occurred in fewer telmisartan-treated patients (28%) than in lisinopril-treated patients (40%; P =.001). Significantly fewer patients (P =.018) receiving telmisartan experienced treatment-related cough (3% v 7%), and cough led to discontinuation significantly less often (P =.007) with telmisartan treatment than with lisinopril treatment (0.3% v 3.1%). In addition, two cases of angioedema were observed, both in the lisinopril group. The selective AT (1) receptor antagonist, telmisartan, is extremely effective in the treatment of mild-to-moderate hypertension both as monotherapy and in combination with HCTZ and is at least comparable in efficacy to lisinopril, with a tolerability profile that may offer advantages in terms of a reduced incidence of adverse events.

Serum creatinine and blood urea nitrogen over a six-year period in the very old. Creatinine and BUN in the very old

In a population of 141 very elderly subjects, there was a small but significant decline in BUN and creatinine at 3 years, which persisted at 6 years although partially attenuated. A similar pattern of falling BUN and creatinine was seen in the 31 subjects who began the study with mild azotemia. There was no significant change in the subjects' mean Body Mass Index during the 6-year period of observation. The azotemic subjects had a rate of death or dropout from the study similar to that of the entire cohort. Mean systolic blood pressure fell by 5.4 mm Hg (p < 0.05) and diastolic blood pressure by 2.1 mm Hg (p = NS) by 6 years. Users of diuretics or NSAID had a mean BUN and creatinine comparable to those not taking these medications. We conclude that BUN and serum creatinine do not necessarily increase with time in the old old, even in those with mild azotemia, hence, several determinations of these parameters may be needed to ensure accuracy. While renal function in the elderly probably does not improve with time, it may stabilize due to improvement in blood pressure. Use of diuretics and NSAID by functioning elderly individuals is not necessarily associated with worsening azotemia.

Secondary prevention of myocardial infarction: role of beta-adrenergic blockers and angiotensin-converting enzyme inhibitors

beta-Blockers reduce cardiovascular death and reinfarction in patients with a history of myocardial infarction (MI), and angiotensin-converting enzyme (ACE) inhibitors provide an overall survival benefit in patients with signs or symptoms of left ventricular (LV) dysfunction and a history of acute MI. Despite this, these agents remain underused in clinical practice. Appropriate patient selection in standard clinical practice should be encouraged in order to achieve a mortality rate reduction comparable to that seen in clinical trials. It appears from the findings of recent studies that the greatest benefit from beta-blocker therapy is achieved in patients who are more than 60 years of age and in patients at moderate or high risk for reinfarction and death (eg, patients with LV dysfunction or arrhythmias or both). Patients with class I-IV heart failure treated with ACE inhibitors have fewer recurrent infarctions, a lower incidence of severe congestive heart failure, and a reduced incidence of total cardiovascular death and sudden cardiac death. In addition to the studies completed in patients with MI, there are ongoing studies evaluating whether or not ACE inhibitors can reduce myocardial ischemic events in patients without a prior infarction who have coronary artery disease or hypertension and preserved LV function. There is also growing evidence that concomitant therapy with a beta-blocker and an ACE inhibitor may reduce mortality rates beyond that observed with ACE inhibitors alone in survivors of MI who have LV dysfunction.

Use of prostacyclin and its analogues in the treatment of cardiovascular disease

Prostacyclin is found in all body tissues and body fluids, and is the major metabolite of arachidonic acid in the vasculature. It is a potent vasodilator that affects both the systemic and pulmonary circulations. Prostacyclin also prevents vascular smooth muscle proliferation and inhibits platelet adhesion and aggregation. These features have made it a very attractive substance for treatment of many different cardiovascular diseases. Epoprostenol, a synthetic prostacyclin, is currently available in parenteral form for the treatment of primary pulmonary hypertension, and has been shown to be a valuable palliative therapy. The drug appears to have limited effectiveness for treating patients with congestive heart failure and coronary artery disease, but has shown some utility in patients with peripheral vascular disease, including Raynaud's phenomenon. Analogues of prostacyclin are now in clinical trials and include iloprost, a stable analogue that has been used intravenously to treat patients with peripheral vascular disease. Other parenteral formulations under investigation include taprostene, ciprostene, and UT-15. Beraprost and cicaprost, are two prostacyclin analogues that can be used in oral form, are being studied in clinical trials.

Comparison of controlled-onset, extended-release verapamil with amlodipine and amlodipine plus atenolol on exercise performance and ambulatory ischemia in patients with chronic stable angina pectoris

This multicenter, randomized, double-blind, parallel group, placebo lead-in, placebo-controlled study compared the antianginal and anti-ischemic effects of once-daily bedtime dosing of controlled-onset extended-release (COER-24) verapamil to a once-daily morning dosing of amlodipine +/- atenolol in patients with chronic stable angina. A total of 551 patients with exercise-induced myocardial ischemia and evidence of coronary artery disease were randomized to a 4-week, forced-dose titration treatment period with (1) COER-24 verapamil 240 mg titrated to 480 mg at bedtime (n = 173), (2) amlodipine 5 mg titrated to 10 mg/day (n = 149), (3) amlodipine 5 mg (titrated to 10 mg) plus atenolol 50 mg/day in the A.M. (n = 154), or (4) placebo (n = 75). Treadmill exercise tolerance testing (standard Bruce protocol), and 48-hour ambulatory electrocardiographic (Holter) monitoring were performed at the end of placebo lead-in and double-blind treatment. Each active treatment significantly improved symptom-limited exercise duration and time to moderate angina (p < or = 0.01 vs placebo). For patients with baseline ischemia, amlodipine resulted in a statistically significant increase in total duration of ischemic episodes compared with placebo, whereas COER-24 verapamil and amlodipine plus atenolol resulted in statistically significant decreases compared with placebo and amlodipine. Heart rate at onset of ischemic episodes and ST product were also significantly increased with amlodipine (p < 0.05) compared with either COER-24 or amlodipine plus atenolol. COER-24 and amlodipine alone or in combination with atenolol improved exercise capacity in patients with angina pectoris. COER-24 verapamil monotherapy or amlodipine plus atenolol combination therapy were more effective than amlodipine monotherapy in decreasing ambulatory myocardial ischemia, especially during the hours of 6 A.M. to 12 noon.

Alpha-adrenergic blocking drugs in clinical medicine

The alpha-adrenergic blockers have played an important role in the treatment of vascular diseases. Nonselective alpha blockers have been used as treatments for patients with severe hypertension, including pheochromocytoma. Selective alpha 1 blockers have been used in the treatment of hypertension and prostatic obstruction, and these drugs have also been considered in the treatment of other vascular and nonvascular conditions. They have unique metabolic actions, specifically on plasma lipids and lipoproteins, which could be of clinical benefit.

Matrix metalloproteinases and abdominal aortic aneurysms: a potential therapeutic target

Abdominal aortic aneurysm (AAA) is a leading cause of death in the United States, and there is no effective treatment in the early course of disease. Therapy to retard or reverse aneurysmal growth requires an understanding of the underlying vascular pathology. Recent research has indicated that enzymatic degradation of structural matrix proteins plays a large role in the formation of AAAs. Specifically, many studies have implicated a family of matrix degrading enzymes, known as matrix metalloproteinases (MMPs), as vital factors in the disease. Although AAA was once thought to be purely secondary to atherosclerosis, investigators have demonstrated various differences between the diseases in both levels and distribution of MMPs, suggesting independent mechanisms. Experimental models have shown that inhibition of these proteinases may slow aortic wall matrix breakdown. The purpose of this article is to review the current literature regarding the role of individual MMPs in AAA, including their complex regulatory mechanisms and possible cellular sources, the importance of MMPs as a potential therapeutic target in the prevention and treatment of AAA, and their inhibition using novel pharmacologic interventions in animal models.

Herbal medicine for the treatment of cardiovascular disease: clinical considerations

Herbs have been used as medical treatments since the beginning of civilization and some derivatives (eg, aspirin, reserpine, and digitalis) have become mainstays of human pharmacotherapy. For cardiovascular diseases, herbal treatments have been used in patients with congestive heart failure, systolic hypertension, angina pectoris, atherosclerosis, cerebral insufficiency, venous insufficiency, and arrhythmia. However, many herbal remedies used today have not undergone careful scientific assessment, and some have the potential to cause serious toxic effects and major drug-to-drug interactions. With the high prevalence of herbal use in the United States today, clinicians must inquire about such health practices for cardiac disease and be informed about the potential for benefit and harm. Continuing research is necessary to elucidate the pharmacological activities of the many herbal remedies now being used to treat cardiovascular diseases.

Sodium ion/hydrogen ion exchange inhibition: a new pharmacologic approach to myocardial ischemia and reperfusion injury

Over the past few years, it has been shown that the cardiac myocyte plasma membrane sodium ion/hydrogen ion exchanger (NHE) plays an important role in the maintenance of intracellular pH, sodium, and calcium ion homeostasis. From the results of various experimental studies, it is clear that this ion exchanger is an important mediator of ischemic-reperfusion injury of the heart. During myocardial ischemia, intracellular acidosis develops quickly, activating the exchanger to extrude H+ into the extracellular environment and bring Na+ into the cell. With further progression of ischemia, the cell is unable to handle the overload of Na+, causing it to use its Na+/Ca2 exchanger to unload intracellular Na+ into the extracellular space. At the same time, however, calcium is being transported into the cell. This can lead to detrimental cardiac injury, such as contracture and necrosis. During myocardial reperfusion, these events are magnified because the return of blood flow lowers the extracellular H+ concentration, stimulating the NHE to extrude more intracellular H+ ion. This leads to intracellular Na+ excess and eventually, intracellular Ca2+ overload and cardiac injury. In an effort to alter these pathophysiologic events, a number of investigators have studied the ability of various NHE inhibitors, such as amiloride, analogues of amiloride, and other drugs (HOE 694, HOE 642), to prevent cardiac ischemic-reperfusion damage. Preliminary results from studies in animal models have revealed that most of these agents are able to attenuate the development of myocardial contracture, infarction, and arrhythmias during both ischemia and reperfusion. Their efficacy and cardioprotective effects in human beings have yet to be determined. These agents appear to be promising not only in the prevention and treatment of ischemic heart disease, but also in avoiding cardiac damage in situations where low-flow states are followed by immediate recovery of flow, as in coronary artery bypass graft surgery, percutaneous transluminal coronary angioplasty, thrombolytic therapy, and coronary arterial vasospasm. This article reviews the physiology of the NHE and analyzes the potential role of NHE inhibitors in the prevention of ischemic-reperfusion injury and other cardiac disease states.

Innovative pharmacologic approaches to cardiopulmonary resuscitation

The survival rate of patients undergoing cardiopulmonary resuscitation (CPR) is 5% to 15%. New treatment approaches under investigation for CPR include the use of vasopressin as a vasopressor, amiodarone for the treatment of ventricular tachyarrhythmia, and adenosine antagonists (i.e., theophylline) for bradyasystolic rhythms. More innovative approaches include the use of thyroid hormone and endothelin.

Biologic markers as predictors of cardiovascular disease

Epidemiologic data obtained over the past 30 years suggest that a number of new biologic markers are associated with increased risk for cardiovascular disease. These include indices related to (1) altered glucose metabolism, particularly insulin resistance; (2) hyperlipidemia; (3) elevated levels of lipoprotein(a) and homocysteine; (4) increased levels of molecules reflecting decreased fibrinolysis and increased activation of the coagulation cascade; (5) elevations in cell adhesion molecules and other markers of endothelial function; and (6) elevations in molecules associated with infection, inflammation, and vascular remodeling. Changes in molecules associated with increased risk usually occur in clusters. This clustering suggests that effective treatment of one marker may have positive effects on multiple markers. Indeed, several studies have demonstrated that therapies designed to reduce hyperlipidemia may also lower the plasma levels of factors associated with increased coagulation and reduced fibrinolysis. Thus, careful assessment of patient risk factors, and the development of therapies directed toward chains of markers associated with increased risk, may significantly alter the course of cardiovascular disease.

Use of angiotensin-converting enzyme inhibitors as monotherapy and in combination with diuretics and calcium channel blockers

Angiotensin-converting enzyme (ACE) inhibitors have earned an important place in medical therapy since their discovery about two decades ago. This family of drug has grown tremendously since the introduction of captopril in 1981. There are currently more than 14 ACE inhibitors in the world and 9 are available in the United States. Although these agents share many similarities, they differ in their pharmacokinetic properties, approved indications, and cost. This paper provides guidance for selection of ACE inhibitors by examining the pharmacokinetics, pharmacodynamics, drug interactions, adverse effects, and cost of these agents. Combination products of ACE inhibitors with either diuretics or calcium channel blockers also are reviewed.

The sodium-calcium ion membrane exchanger: physiologic significance and pharmacologic implications

The Na(+)-Ca2+ exchanger is a non-ATP-dependent protein that, under steady-state conditions, extrudes Ca2+ from the interior of the cell into the extracellular space via facilitated transport. The activity of the exchanger seems to be reduced in myocardial ischemia, leading to increased intracellular Ca2+ in the ischemic heart, which can result in arrhythmia, myocardial stunning, and necrosis. In contrast, congestive heart failure and myocardial hypertrophy are associated with increased exchanger activity and a decreased inotropic state. Pharmacologic agents are being developed to modulate sodium ion levels in the cell, which could enhance or reduce sodium-calcium exchange as needed in various pathophysiologic states. At this time there are no available drugs that act specifically on the Na(+)-Ca2+ exchanger itself. The exchanger has been cloned, and inhibitory peptides of the exchanger may soon be available for possible use in treatment of congestive heart failure.

Innovative drug treatments for viral and autoimmune myocarditis

Myocarditis has been shown to be a common cause of cardiomyopathy and is believed to account for 25% of all cases in human beings. Unfortunately, the disease is difficult to detect before a myopathic process ensues. Treatment of myocarditis-induced heart failure includes the standard regimen of diuretics, digoxin, angiotensin-converting enzyme inhibitors, and currently, beta-adrenergic blockers. Treatment of myocarditis itself is dependent on the etiology of the illness. Treatments under investigation include immunosuppressants, nonsteroidal antiinflammatory agents, immunoglobulins, immunomodulation, antiadrenergics, calcium-channel blockers, angiotensin-converting enzyme inhibitors, nitric oxide inhibition (e.g., aminoguanidine), and antiviral agents. Despite advances in treatment, more work needs to be done in the early detection of myocarditis. Additionally, better means need to be established for distinguishing between viral and autoimmune forms of the disease, so that appropriate treatment can be instituted.