Aim. To evaluate the impact of intake of cardiac drugs on adaptation to abnormal heat in patients with cardiovascular diseases (CVD). Subjects and methods. The study covered 188 patients with CVD, who had visited the Research Dispensary Department in January 2011. General clinical examination, biochemical blood analysis, and electrocardiography were made; the hospital anxiety and depression scale, the visual analog scale, and the questionnaire specially developed for this investigation were used. The authors considered acute myocardial infarction, acute stroke, hospital admission, a medical emergency team call, temporary disability (days), hypertensive crises, and unplanned visits to a doctor as estimated outcomes (endpoints) and the number of undesirable reactions a week during the abnormal heat and from September to December 2010 as a combined endpoint. Results. There were a larger number of weekly adverse reactions than usual and a reduction in quality of life (QL) during the abnormal heat. Both an increase and a reduction in the dose of cardiac drugs during the abnormal heat were associated with its worse tolerability. The use of angiotensin-converting enzyme (ACE) inhibitors and calcium channel blockers (CCB) was an independent factor associated with the smaller number of complications during the abnormal heat. That of diuretics was an independent factor that was associated with a more decrease in QL in elderly patients during the heat. The intake of angiotensin receptor blockers (ARB) or nitrates was an independent factor associated with the larger number of complications during the abnormal heat. Conclusion. The use of ACE inhibitors and CCB is associated with fewer complications during the abnormal heat of 2010. The intake of diuretics in patients over 65 years of age and that of ARB or nitrates was associated with worse heat tolerance.