Carvedilol

Carvedilol Side Effects: Carvedilol, brand name Coreg, is a medication in the beta-blocker class of drugs. Carvedilol is most commonly used in the treatment of congestive heart failure where it is the beta-blocker with the most data for reduction of heart failure symptoms and hospitalizations. Carvedilol is available in 3.125 mg, 6.25 mg, 12.5 mg and 25 mg doses. The maximum Carvedilol dosage is 25 mg twice daily. Carvedilol is also available in a sustained release product Coreg CR in doses of 10mg, 20 mg and 40 mg, and 80 mg. Most of the carvedilol side effects are common to the class of beta-blocker medications and are predictable from the mechanism of action, competitive inhibition of the beta adrenergic receptor sites. Stimulation of the beta adrenergic sites causes increased heart rate, increased myocardial muscle contractility, bronchodilation, and peripheral vasodilation. Beta-blockers therefore can lead to bradycardia, decreased cardiac contractility, bronchospasm and peripheral vasoconstriction. Most of the carvedilol side effects can be explained on the basis of its beta-blocker mechanism of action. FDA approved indications for carvedilol include treatment of hypertension, congestive heart failure and for prevention of adverse events and death post myocardial infarction.

Common Carvedilol Side Effects: Unfortunately mild to moderate carvedilol side effects are fairly common. These include those related to excess beta blockade including hypotension, bradycardia, dyspnea, edema, abnormal respiratory sounds on auscultation called rales or crackles, dizziness, and pulmonary edema. Fatigue, weight gain, asthenia, abnormal vision, and angina are other common carvedilol side effects. Gastrointestinal common carvedilol side effects include nausea, vomiting and elevation of liver transaminases. Various other carvedilol side effects include hyperglycemia, headache, joint pains, anemia and elevation of serum cholesterol.

Serious Carvedilol Side Effects: Some of these are also not rare, and carvedilol use requires supervision by your health care provider to watch for any of these serious carvedilol side effects. They can include several that are predictable based on excessive beta-blockade including congestive heart failure, heart block, severe bradycardia, asthma and bronchospasm. Less predictable include several severe dermatologic carvedilol side effects like Stevens-Johnson Syndrome, toxic epidermal necrolysis, erythema multiforme, photosensitivity, and exfoliative dermatitis. Other allergic appearing carvedilol side effects include anaphylactoid reactions, hypersensitivity reactions, interstitial pneumonitis, and lupus erythematosis. Serious carvedilol side effects of the hematopoietic system include leukopenia, thrombocytopenia, anemia and aplastic anemia. A strange carvedilol side effect is what is called intraoperative floppy iris syndrome which can cause complications during cataract surgery.

Cautions and Drug Interactions: Carvedilol should be avoided or special caution used in many situations. You should never take any prescription medications without consultation with your health care provider, but this is especially true of the beta-blockers. Abrupt discontinuation of carvedilol can lead to rebound tachycardia and complications including heart attack and severe arrhythmias and death. A taper over 1-2 weeks from higher doses of carvedilol is strongly recommended. Carvedilol is use in treatment of congestive heart failure, but use should be delayed until good management of fluid overload is accomplished, and initiation of carvedilol therapy can lead to exacerbation of CHF symptoms in some patients that requires careful fluid status management. Carvedilol use is cautioned in a wide variety of health conditions including asthma and bronchospasm, Prinzmetal angina (coronary artery vasospasm), most causes of bradycardia especially atrioventricular block, in major surgery, in peripheral vascular disease, in diabetes mellitus, in conditions where unmasking of alpha adrenergic overload might be problematic like pheochromocytoma, in myasthenia gravis, and in many other conditions. See the manufacturer’s prescribing guidelines for complete details.

Drug interactions with carvedilol are also common. Again see the manufacturer’s prescribing guidelines for a complete list of potential drug interactions, but consult your pharmacist for specific concerns about medications you may be taking or considering taking. Some of the more commonly used drugs with potential interactions include cimetadine, insulins, NSAIDs, decongestants, several antiarrythmic drugs including amiodarone and the calcium channel blockers, carebamazepine, any drugs dependent on the CYP 450 2D6 pathway, digoxin, citalopram, several anticonvulsant medications, and some herbal products including willow bark.

Pregnancy and Lactation: Carvedilol is pregnancy category C, and its safety in breast feeding is unknown.

Unusual Carvedilol Side Effects: The propensity for weight gain is a bit unusual, but the floppy iris syndrome is possibly the most unusual carvedilol side effect.

General Considerations: Probably the most important issues to know when taking carvedilol are that a taper off the drug is important to avoid reflex tachycardia and potential serious consequences including heart attack, angina pectoris and lethal cardiac arrhythmias. In addition exacerbation of asthma and general fatigue, bradycardia and weight gain can be subtle but important to recognize carvedilol side effects.

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