Nadolol is one of the typical non-cardioselective beta-adrenoceptor antagonists (first generation beta-blocker) which acts on both beta-1 and beta-2 adrenoceptors equally but has weak activity on beta-3 subtype.
It is also an inverse agonist that reduces resting heart rate as well. It increases sinus cycle length, slows heart rate, decreases AV nodal conduction and increases AV nodal refractoriness.
It also prolongs AV monophasic action potentials. It is the longest-acting beta-blocker and its duration of action is up to 24 hours.
Additionally, it is less lipid-soluble than other blockers and probably enters the central nervous system (CNS) to a lesser extent.
Nadolol is almost like propranolol and it is widely prescribed to treat a variety of medical disorders such as:
- Cardiac dysarrhythmia (e.g. supraventricular and ventricular arrhythmias, acute arrhythmias)
- Angina pain
- Myocardial infarction
- Migraine prophylaxis
- Fallot’s tetralogy
- Anxiety states
- Hypertrophic obstructive cardiomyopathies etc.
Use of nadolol is contraindicated in bronchial asthma, bronchospasm, history of obstructive airway disease, bradycardia (heart rate less than 55/min), cardiogenic shock, 2nd and 3rd degree AV block, metabolic acidosis etc.
Patients with left ventricular failure or severe uncompensated CCF should not use this medicine. Diabetic patients who are receiving hypoglycemic agent mainly insulin are not given this drug.
Nadolol therapy to the patients with peripheral vascular disease (e.g. Buerger’s disease) aggravates the condition.
Hypotensive patients with systolic blood pressure less than 90 mm Hg are strongly prohibited to take such medications.
Before you start any drug therapy you should know all about the risks and benefits of such medications.
Always try to give the appropriate information regarding your past and present illness to your doctor. You should arrange adequate visits to your doctor in order to have proper monitoring.
Never forget to tell about the diseases like asthma, diabetes, myocardial infarction, heart failure, renal impairment etc. if you have had.
Nadolol is the drug which is contraindicated in asthmatics. It may mask the symptoms of hyperthyroidism and/or hypoglycemia. It may unmask myasthenia gravis.
Worsening of psoriasis has been reported associated with beta-blockers. So, try to follow each and every direction given by your doctor for your betterment.
In case supraventricular and ventricular arrhythmias, you should take 80 mg daily in 1-2 divided doses. You may need to increase the dose of nadolol.
It should not be done gradually rather than abruptly. The usual therapeutic dose of nadolol is regarded as 160-320 mg/day.
Although nadolol is well tolerated by most of the patients, but it may bring unwanted effects like nausea, sleep disorders, lassitude, diarrhea, palpitations, bradycardia, weakness, dyspnea, decreased sexual activity, impotence, extremity pain, back pain, asthma, visual disturbances, cardiac arrhythmias etc.
If the drug is withdrawn abruptly, rebound angina and myocardial infarction may occur. Potentially fatal medical emergencies like polymorphic ventricular tachycardia, rebound hypertension etc. also happen but rarely.
Sometimes you may need to consult with the doctor if you feel any of these discomforts. Firstly, you have to stop using this drug and then consult with your physician immediately.
In the case of children, be careful not to exceed the maximum safe dose. You should not take certain medicines during this drug therapy.
It is safe to consult with your doctor if you are in need of some drugs for another health problem.
Additive depression of sinus node and A-V conduction take place when nadolol is concurrently taken with digitalis and verapamil.
Digitalis increases the risk of bradycardia and even cardiac arrest may also occur in some cases. There is also enhanced the risk of arrhythmias with diuretics.
Rebound hypertension may happen with clonidine. When used with indomethacin or other NSAIDs there is decreased beta blockers effect. Cimetidine inhibits nadolol metabolism.
However, the dose range of nadolol is wide, and this may not be clinically significant.
On the other hand, nadolol retards lidocaine metabolism by reducing hepatic blood flow resulting in more toxicity.
It also increases the bioavailability of chlorpromazine by decreasing its first pass metabolism.
Prolonged refractoriness with disopyramide, quinidine, procainamide, amiodarone, and bepridil has been reported. Moreover, nadolol prolongs QT interval with TCAs, phenothiazines, terfenadine and astemizole.
There is increased the risk of medical emergency when used with potassium-depleting diuretics, intravenous erythromycin, halofantrine, pentamidine, and quinolones.
When it used in diabetic persons who are receiving insulin or with sulphonylureas there is more hypoglycemia. It may prolong neuromuscular blockade of tubocurarine.
AV block becomes worse when beta blocker i.e. nadolol is used with calcium channel antagonists. Potentially fatal conditions arise with verapamil and diltiazem.
Because of such a wide variety of drug interactions, you should be more conscious about using other drugs during or before you start the nadolol therapy and even after completion of therapy.
There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Gradual withdrawal is recommended in pregnancy, renal insufficiency, and compensated heart failure.