Carvedilol has been evaluated for safety in hypertension in more than 2,193 patients in U.S. clinical trials and in 2,976 patients in international clinical trials. Approximately 36% of the total treated population received carvedilol for at least 6 months. Most adverse events reported during therapy with carvedilol were of mild to moderate severity. In U.S. controlled clinical trials directly comparing carvedilol in doses up to 50 mg (n = 1,142) to placebo (n = 462), 4.9% of patients receiving carvedilol discontinued for adverse events vs. 5.2% of placebo patients. Although there was no overall difference in discontinuation rates, discontinuations were more common in the carvedilol group for postural hypotension (1% vs. 0). The overall incidence of adverse events in U.S. placebo-controlled trials increased with increasing dose of carvedilol. For individual adverse events this could only be distinguished for dizziness, which increased in frequency from 2% to 5% as total daily dose increased from 6.25 mg to 50 mg.
Table 1 shows adverse events in U.S. placebo-controlled clinical trials for hypertension that occurred with an incidence of > 1% regardless of causality, and that were more frequent in drug-treated patients than placebo-treated patients.
Table 1. Adverse Events (%) Occurring in U.S. Placebo-Controlled Hypertension Trials (Incidence ≥ 1%, Regardless of Causality)Shown are events with rate > 1% rounded to nearest integer.
| Carvedilol | Placebo |
(n = 1,142) | (n = 462) |
Cardiovascular | | |
Bradycardia | 2 | — |
Postural hypotension | 2 | — |
Peripheral edema | 1 | — |
Central Nervous System | | |
Dizziness | 6 | 5 |
Insomnia | 2 | 1 |
Gastrointestinal | | |
Diarrhea | 2 | 1 |
Hematologic | | |
Thrombocytopenia | 1 | — |
Metabolic | | |
Hypertriglyceridemia | 1 | — |
Dyspnea and fatigue were also reported in these studies, but the rates were equal or greater in patients who received placebo.
The following adverse events not described above were reported as possibly or probably related to carvedilol in worldwide open or controlled trials with carvedilol in patients with hypertension.
Incidence > 0.1% to ≤1%
Cardiovascular: Peripheral ischemia, tachycardia
Central and Peripheral Nervous System: Hypokinesia
Gastrointestinal: Bilirubinemia, increased hepatic enzymes (0.2% of hypertension patients were discontinued from therapy because of increases in hepatic enzymes) [see Adverse Reactions (6.2)]
Psychiatric: Nervousness, sleep disorder, aggravated depression, impaired concentration, abnormal thinking, paroniria, emotional lability
Respiratory System: Asthma [see Contraindications (4)]
Reproductive, male: Decreased libido
Skin and Appendages: Pruritus, rash erythematous, rash maculopapular, rash psoriaform, photosensitivity reaction
Special Senses: Tinnitus
Urinary System: Micturition frequency increased
Autonomic Nervous System: Dry mouth, sweating increased
Metabolic and Nutritional: Hypokalemia, hypertriglyceridemia
Hematologic: Anemia, leukopenia
The following events were reported in ≤ 0.1% of patients and are potentially important: Complete AV block, bundle branch block, myocardial ischemia, cerebrovascular disorder, convulsions, migraine, neuralgia, paresis, anaphylactoid reaction, alopecia, exfoliative dermatitis, amnesia, GI hemorrhage, bronchospasm, pulmonary edema, decreased hearing, respiratory alkalosis, increased BUN, decreased HDL, pancytopenia, and atypical lymphocytes.
The mechanism by which β-blockade produces an antihypertensive effect has not been established.
β-adrenoreceptor blocking activity has been demonstrated in animal and human studies showing that carvedilol (1) reduces cardiac output in normal subjects; (2) reduces exercise- and/or isoproterenol-induced tachycardia; and (3) reduces reflex orthostatic tachycardia. Significant β-adrenoreceptor blocking effect is usually seen within one hour of drug administration.
α1-adrenoreceptor blocking activity has been demonstrated in human and animal studies, showing that carvedilol (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.
Due to the α1-receptor blocking activity of carvedilol, blood pressure is lowered more in the standing than in the supine position, and symptoms of postural hypotension (1.8%), including rare instances of syncope, can occur. Following oral administration, when postural hypotension has occurred, it has been transient and is uncommon when carvedilol is administered with food at the recommended starting dose and titration increments are closely followed [see Dosage and Administration (2)].
In hypertensive patients with normal renal function, therapeutic doses of carvedilol decreased renal vascular resistance with no change in glomerular filtration rate or renal plasma flow. Changes in excretion of sodium, potassium, uric acid, and phosphorus in hypertensive patients with normal renal function were similar after carvedilol and placebo.
Carvedilol has little effect on plasma catecholamines, plasma aldosterone, or electrolyte levels, but it does significantly reduce plasma renin activity when given for at least 4 weeks. It also increases levels of atrial natriuretic peptide.