The relationship between drugs and cardiovascular disease can be difficult to quantify. This is in part due to the high rate of cardiovascular disease and the high number of cardiovascular risk factors. In some cases in which a drug can be conclusively linked to an adverse cardiovascular reaction, the reaction is an exaggerated but otherwise normal response to the drug, such as when postural hypotension (low blood pressure) is caused by an antihypertensive agent. In other cases, however, the reaction is an aberrant effect unrelated to the drug’s therapeutic action.
Among the more frequent cardiovascular disorders induced by drugs are cardiac arrhythmias, changes in blood pressure, vascular spasm, and heart failure. An outline of these and other commonly drug-induced cardiac disorders follows:
- Arrhythmias – including ventricular tachycardia (rapid heartbeat that starts in the ventricles), atrial fibrillation (rapid heart rate in which the upper heart chambers contract abnormally), and bradycardia (slow heart rate). Ironically, drug-induced arrhythmias are most commonly caused by drugs used to treat cardiac rhythm disturbances
- Depression of cardiac function
- Disorders of heart muscle – including cardiomyopathy (weakening or change in the structure of the heart muscle), which is known to be caused by the antineoplastic agents daunorubicin (Cerubidine) and doxorubicin (Adriamycin), myofibrillar degeneration (a common lesion of the heart muscle), myocardial necrosis and focal degeneration
- Myocardial ischemia (oxygen deprivation to the heart muscle accompanied by inadequate removal of metabolites due to reduced blood flow) – including coronary artery and cerebrovascular disease
- Hypertension – most drugs that induce a chronic rise in blood pressure do so by causing retention of water and salt. But acute rises in blood pressure can also be induced by interactions between tricyclic antidepressants and adrenergic neurone-blocking drugs such as bethanidine, guanethidine, and debrisoquine. Among other drugs that can precipitate dangerous systemic rises in blood pressure include vassopressor agents such as angiotensin and noradrenaline
- Hypotension – in addition to hypotensive agents, other drugs such as the phenothiazines can lower blood pressure unintendedly, especially when given with antihypertensive agents. Numerous central depressant drugs can also cause an unpredictable fall in blood pressure, especially among the elderly
- Peripheral arterial spasm – can develop in those who take preparations containing ergot to excess for migraines. Intravenous barbiturates and diazepam can also cause the condition when mistakenly injected intra-arterially
- Thrombophlebitis and venous thrombosis – the drugs most often implicated include vancomycin, amphotericin B, high-concentration sugar solutions, diazepam, and contraceptive steroids
See also:
Valvular heart disease
Pulmonary hypertension
Pulmonary vascular disease