Carvedilol has been evaluated for safety in hypertension in more than 2,193 subjects in U.S. clinical trials and in 2,976 subjects in international clinical trials. Approximately 36% of the total treated population received Carvedilol. Most adverse events reported during therapy with carvedilol tablets were of mild to moderate severity. In U.S. controlled clinical trials directly comparing carvedilol tablets in doses up to 50 mg (n = 1,142) with placebo (n = 462), 4.9% of subjects receiving carvedilol tablets discontinued for adverse events versus 5.2% of placebo subjects. Although there was no overall difference in discontinuation rates, discontinuations were more common in the carvedilol group for postural hypotension (1% versus 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 2shows adverse events in U.S. placebo‑controlled clinical trials for hypertension that occurred with an incidence of greater than or equal to 1% regardless of causality and that were more frequent in drug‑treated subjects than placebo‑treated subjects.
Table 2. Adverse Events (%) Occurring in U.S. Placebo-Controlled Hypertension Trials (Incidence ≥1%, Regardless of Causality)
aBody System/ | 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 | — |
a Shown are events with rate >1% rounded to nearest integer.
Dyspnea and fatigue were also reported in these trials, but the rates were equal or greater in subjects 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 subjects with hypertension or heart failure.
Incidence greater than 0.1% to less than or equal to 1%
Cardiovascular:Peripheral ischemia, tachycardia.
Central and Peripheral Nervous System:Hypokinesia.
Gastrointestinal:Bilirubinemia, increased hepatic enzymes (0.2% of hypertension patients and 0.4% of heart failure 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 less than or equal to 0.1% of subjects 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 1 hour of drug administration.
α
1-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 α
1-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.