Side Effects of Corgard (nadolol)

Corgard (nadolol) is a beta-blocker used to treat high blood pressure (hypertension) and heart pain (angina).

Norepinephrine and epinephrine (adrenaline) are chemicals released within the body that attach to receptors on several types of cells, including nerves and some muscles, and change the way the cells function, either stimulating the cells or suppressing them. Corgard prevents norepinephrine and epinephrine from binding to beta receptors on nerves.

By blocking the effect of norepinephrine and epinephrine, beta-blockers reduce heart rate, reduce the force of the heart's contractions, and reduce blood pressure by relaxing the muscles surrounding the blood vessels.

Heart pain (angina) occurs when the workload of the heart requires more oxygen than the blood can supply. By slowing the heart rate and decreasing the force of contractions of the heart, Corgard reduces the demand of the heart's muscle for oxygen and thereby prevents angina.

Beta-blockers may cause difficulty breathing since they cause the muscles surrounding the air passages of the lung to contract, thus narrowing the air passages and making it more difficult for air to pass through. 

Common side effects of Corgard include

• abdominal cramps,
• diarrhea,
• constipation,
• fatigue,
• insomnia,
• nausea,
• depression,
• impotence,
• lightheadedness,
• slow heart rate,
• low blood pressure,
• cold extremities,
• sore throat, and
• shortness of breath or wheezing.

Serious side effects of Corgard include

• increased breathing difficulties in patients with asthma, chronic bronchitis, or emphysema;
• dangerously slow heart rates, and even shock in patients with existing slow heart rates and heart blocks; and
• increased symptoms of heart failure.

Drug interactions of Corgard include diltiazem, amiodarone, or digoxin, because combining these with Corgard can cause complete block of the heart's electrical system, a life-threatening condition.

• Nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the blood pressure lowering effects of beta-blockers.
• Corgard can mask the early warning symptoms of low blood sugar (hypoglycemia) and should be used with caution in patients receiving treatment for diabetes.

Safe use of Corgard during pregnancy has not been established.

Corgard is excreted into breast milk. Corgard should not be used while breastfeeding because of the potential risk of adverse effects in the nursing infant.

Nadolol is generally well tolerated. Side effects include

• abdominal cramps,
• diarrhea,
• constipation,
• fatigue,
• insomnia,
• nausea,
• depression,
• impotence,
• lightheadedness,
• slow heart rate,
• low blood pressure,
• cold extremities,
• sore throat, and
• shortness of breath or wheezing.

Nadolol can increase breathing difficulties in patients with

• asthma,
• chronic bronchitis, or
• emphysema.

In patients with existing slow heart rates (bradycardias) and heart blocks (defects in the electrical conduction of the heart), nadolol can cause dangerously slow heart rates, and even shock. Nadolol reduces the force of heart muscle contraction and can increase symptoms of heart failure.

In patients with coronary artery disease, abruptly stopping nadolol can suddenly worsen angina and occasionally precipitate heart attacks. If it is necessary to discontinue nadolol, its dose should be reduced gradually over several weeks.

Most adverse effects have been mild and transient and have rarely required withdrawal of therapy.

Cardiovascular

Bradycardia with heart rates of less than 60 beats per minute occurs commonly, and heart rates below 40 beats per minute and/or symptomatic bradycardia were seen in about 2 of 100 patients.

Symptoms of peripheral vascular insufficiency, usually of the Raynaud type, have occurred in approximately 2 of 100 patients. Cardiac failure, hypotension, and rhythm/conduction disturbances have each occurred in about 1 of 100 patients. Single instances of first degree and third degree heart block have been reported; intensification of AV block is a known effect of beta-blockers.

Central Nervous System

Dizziness or fatigue has been reported in approximately 2 of 100 patients; paresthesias, sedation, and change in behavior have each been reported in approximately 6 of 1000 patients.

Respiratory

Bronchospasm has been reported in approximately 1 of 1000 patients.

Gastrointestinal

Nausea, diarrhea, abdominal discomfort, constipation, vomiting, indigestion, anorexia, bloating, and flatulence have been reported in 1 to 5 of 1000 patients.

Miscellaneous

Each of the following has been reported in 1 to 5 of 1000 patients: rash; pruritus; headache; dry mouth, eyes, or skin; impotence or decreased libido; facial swelling; weight gain; slurred speech; cough; nasal stuffiness; sweating; tinnitus; blurred vision. Reversible alopecia has been reported infrequently.

The following adverse reactions have been reported in patients taking nadolol and/or other betaadrenergic blocking agents, but no causal relationship to nadolol has been established.

Central Nervous System

Reversible mental depression progressing to catatonia; visual disturbances; hallucinations; an acute reversible syndrome characterized by disorientation for time and place, short-term memory loss, emotional lability with slightly clouded sensorium, and decreased performance on neuropsychometrics.

Gastrointestinal

Mesenteric arterial thrombosis; ischemic colitis; elevated liver enzymes.

Hematologic

Agranulocytosis; thrombocytopenic or nonthrombocytopenic purpura.

Allergic

Fever combined with aching and sore throat; laryngospasm; respiratory distress.

Miscellaneous

Pemphigoid rash; hypertensive reaction in patients with pheochromocytoma; sleep disturbances; Peyronie's disease.

The oculomucocutaneous syndrome associated with the beta-blocker practolol has not been reported with nadolol.

When administered concurrently, the following drugs may interact with beta-adrenergic receptor blocking agents:

Anesthetics, general

exaggeration of the hypotension induced by general anesthetics.

Antidiabetic drugs (oral agents and insulin)

hypoglycemia or hyperglycemia; adjust dosage of antidiabetic drug accordingly.

Catecholamine-depleting drugs (e.g., reserpine)

additive effect; monitor closely for evidence of hypotension and/or excessive bradycardia (e.g., vertigo, syncope, postural hypotension).

Digitalis glycosides

Both digitalis glycosides and beta-blockers slow atrioventricular conduction and decrease heart rate. Concomitant use can increase the risk of bradycardia.

Response to Treatment for Anaphylactic Reaction

While taking beta-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.