Carvedilol blood pressure

DW, a 78-year-old Caucasian man, presents to the emergency room with complaints of a headache persisting over the last 3 days. Repeated blood pressure measurements average 200/11 0 mm Hg. He reports no other symptoms and physical examination and laboratory tests are unremarkable as is his past medical history with the exception of hypertension diagnosed in his early 60s. DW reports that he is struggling on a fixed retirement income with no prescription coverage and takes "what I can afford." Blood pressure medications are carvedilol 25 mg twice daily, amlodipine 10 mg once daily, torsemide (Demadex )... 

Apart from possible clinical differences between the P-block-ers approved for HF, selection of a p-blocker may also be affected by pharmacologic differences. Carvedilol exhibits a more pronounced blood pressure lowering effect and thus causes more frequent dizziness and hypotension as a consequence of its ar receptor blocking activity. Therefore, in patients predisposed to symptomatic hypotension, such as those with advanced LV dysfunction (LVEF less than 20%) who normally exhibit low systolic blood pressures, metoprolol succinate may be the most desirable first-line P-blocker. In patients with uncontrolled hypertension, carvedilol may provide additional antihypertensive efficacy. 

Blood pressure reduction may be particularly pronounced after initiation and dose titration of 3-blockers that also possess a-blocking effects (e.g., labetalol and carvedilol). 

Carvedilol also (1) attenuates the pressor effects of phenylephrine, (2) causes vasodilation, and (3) reduces peripheral vascular resistance. These effects contribute to the reduction of blood pressure and usually are seen within 30 minutes of drug administration. 

Hypersensitivity reactions While taking -blockers, patients with a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge, either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction. Renal/Hepatic function impairment Rarely, use of carvedilol in patients with CHF has resulted in deterioration of renal function. Patients at risk appear to be those with low blood pressure (systolic BP less than 100 mm Hg), ischemic heart disease. 

Carvedilol significantly reduces systemic blood pressure, pulmonary artery pressure, right atrial pressure, systemic vascular resistance, and heart rate, while stroke volume index is increased. 

Carvedilol Competitively blocks receptors (see Chapter 10) Slows heart rate reduces blood pressure poorly understood effects reduces heart failure mortality Chronic heart failure To slow progression reduce mortality in moderate and severe heart failure many other indications in Chapter 10. Oral duration 10-12 h Toxicity Bronchospasm, bradycardia, atrioventricular block, acute cardiac decompensation t see Chapter 10 for other toxicities and interactions... 

Renal insufficiency can occur in patients with heart failure treated with carvedilol, usually when pre-existing renal insufficiency, low blood pressure, or diffuse vascular disease are present (2). Patients at high risk of renal dysfunction should be carefully monitored, particularly at the beginning of treatment, and the drug should be withdrawn in case renal function worsens. 

In a comparison of carvedilol with valsartan in 160 patients with hypertension (mean age 46 years) each treatment was continued for 16 weeks, with crossover after 4 weeks of placebo (9). Blood pressure was significantly lowered by both drugs (48% normalization with valsartan and 45% with carvedilol). In the first month of treatment, sexual activity (assessed as the number of episodes of sexual intercourse per month) fell with both treatments compared with baseline, although the change was statistically significant only with carvedilol. After the first month of treatment, sexual activity further worsened with carvedilol, but it improved or recovered fully with valsartan. The results were confirmed by the crossover. This confirms that beta-blockers can cause chronic worsening of sexual function. 

Effects on blood pressure and heart rate The hypertensive effects of adrenaline (epinephrine) can be markedly increased in patients taking non-selective beta blockers such as propranolol. A severe and potentially life-threatening hypertensive reaction and/or marked bradycardia can develop. Cardioselective beta blockers such as atenolol and metoprolol interact minimally. An isolated report describes a fatal hypertensive reaction in a patient given propranolol and phenylephrine, but concurrent use normally seems to be uneventful Paradoxically, marked hypotension occurred in one patient given low-dose carvedilol and dobutamine. Anaphylaxis Some evidence su ests that anaphylactic shock in... 

Dobutamine is a betaj, beta2 and alphaj adrenergic agonist and carvedilol is a non-selective beta blocker, but at low doses it is primarily a selective betaj adrenergic antagonist and it is also an alphaj antagonist. It was proposed that the drop in blood pressure was caused by vasodilation due to vascular beta2 receptor activation, which was not blocked by low doses of carvedilol. ... 

In 12 healthy subjects carvedilol 25 mg twice daily for 7 to 9 days did not alter the effeets of a single 2-mg intravenous dose of levosimendan on cardiac contractility. In addition, the heart rate and diastolic blood pressure responses were not altered, but the systolie blood pressure response was blunted. In a study to eompare levosimendan with dobutamine in patients with severe, low-output heart failure, 33 of the 102 patients receiving levosimendan were also given unnamed beta bloekers. The use of a beta blocker was shown not to reduee the haemodynamie effeets of levosimendan. The authors say this suggests that there may be a place for levosimendan in the management of exaeerbations of heart failure not eontrolled by beta bloekers. ... 

Cardiovascular Takotsubo cardiomyopathy [SEDA-33, 313] has been attributed to high-dose dopamine in a 78-year-old woman who had acute coronary syndrome. Her blood pressure was low and the intraventricular pressure was high during dopamine infusion she improved when the dopamine was gradually withdrawn and carvedilol was added [60" ]. 

A 76-year-old woman who was taking carvedilol for hypertension and paroxysmal supraventricular dysrhythmias had an attack of transient syncope after taking a single dose of propafenone 600 mg. Her blood pressure was 110/60 mmHg, heart rate 68/minute, and an electrocardiogram showed left bundle branch block and first degree atrioventricular... 

Drug overdose An 84-year-old man took total of 60 (6.25 mg) tablets and rapidly developed hypotension (systolic blood pressure 70 mmHg), bradycardia (45/ minute), and a junctional rhythm [6" ]. He was given intravenous glucagon and dopamine infusion and recovered after 14 hours. The carvedilol serum concentration was 472 pg/1, compared with a predicted steady-state concentration of 8.5 pg/1 during treatment with 6.25 mg bd. 

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