Low blood pressure
The patients with low blood pressure conditions are at an increased risk when using this medicine. If low blood pressure (less than 90 mmHg) occurs, Metoprolol should be gradually decreased or discontinued and access the status of blood flow and damage to heart muscle. The measurement of arterial pressure (using central venous, pulmonary capillary wedge) may be required. A temporary mechanical blood circulation support, positive inotropic agents, or fluids are given to the patients. If low blood pressure occurs due to sinus low heart rate or AV block, it should be treated accordingly.
Metoprolol slows the atrioventricular conduction which results in fluid accumulation in the lungs, atrioventricular block (AV block), and shock
. It may also cause first, second, or third-degree heart block. If a heart block occurs, discontinue using this medicine and atropine (0.25-0.5 mg) should be injected in the vein. If atropine treatment doesn't work, Metoprolol should be discontinued, provide isoproterenol carefully or pacemaker installation in heart should be considered.
Decreased heartbeat (bradycardia)
The patients with abnormal heart rate are at increased risk while using this medicine for treatment of heart failure. The sinus heart rate is decreased in patients suffering from heart failure. In addition, Metoprolol also causes a decrease in sinus heart rate. This risk is high in the patients with increased initial heart rate and less in patients with low initial heart rates. If a decrease in sinus heart rate (<40 beats per min) and cardiac output is seen, atropine (0.25-0.5 mg) should be injected in the vein. If atropine treatment doesn't work, Metoprolol should be discontinued, provide isoproterenol carefully or pacemaker installation in heart should be considered.
Patients with reduced blood supply to limbs
The patients with reduced blood supply to limbs such as Raynaud's disease are at increased risk while using this medicine. Such patients are at increased risk of developing low blood pressure conditions. Metoprolol should be used with caution in these patients.
Elevated thyroid hormone level (thyrotoxicosis)
The patients using Metoprolol are at increased risk of developing an increase in the thyroid hormone
level. The use of beta-adrenergic blockers may mask the symptoms of an increased level of thyroid hormone, such as increased heartbeat. The patients should be carefully monitored to avoid immediate withdrawal of Metoprolol, which may cause an increase in the level of thyroid hormone.
Patients with diabetes
are at increased risk when using this medicine. Beta-blockers
including Metoprolol may affect the breakdown of glucose. In addition, Beta-blockers also hide the symptoms of low blood glucose level such as increased heart rate. Metoprolol should be used with caution in these patients. In patients with insulin-dependent and labile diabetes, the dose adjustment of blood sugar lowering medicines may be necessary.
Patients undergoing surgery
and having a risk factor of heart and blood vessels diseases are at increased risk when using this medicine. These patients may suffer from decreased heartbeat, stroke
, long-term low blood pressure and can be possibly fatal. The anesthetist should be informed about the use of Metoprolol before undergoing surgery. The treatment with high dose Metoprolol in patients undergoing non-cardiac surgery should be avoided.
Contraction of the airways (bronchospastic diseases)
Patients with bronchospastic diseases are at increased risk when using this medicine. The Metoprolol should be used with caution in these patients. A lower dose of Metoprolol or a beta-2 stimulant (for example, terbutaline) should be used in combination with Metoprolol. Discontinue this medicine if bronchospasm related to congestive heart failure occurs.
Patients without a history of heart diseases
Patients with ischemic heart disease are at increased risk when discontinuing the use of Metoprolol abruptly. These patients may suffer from worsening of angina
, abnormal heartbeat, increased blood pressure, and, in some cases, a heart attack may occur. When the long-term used Metoprolol is discontinued, especially in the patients with ischemic heart disease, the dose of Metoprolol should be gradually decreased for 1-2 weeks until the patient is taking 25 mg of Metoprolol per dose. The lowest dose should be taken for at least 4 days before discontinuing the medicine. The careful monitoring of the patient is advised. If angina worsens or coronary insufficiency occurs, Metoprolol should be given quickly, at least temporarily, and other measures suitable for controlling unstable angina should be used. Patients should be warned for not to discontinue the therapy without the doctor’s advice. Metoprolol should not be stopped abruptly even if it is used only for high blood pressure.
Patients with a history of congestive heart failure controlled by diuretics
and digitalis are at increased risk when using this medicine. These patients may suffer from depressed contractility of heart muscles causing or worsening heart failure. As Metoprolol and digoxin both decreases the atrioventricular conduction and thus there is a risk of atrioventricular dissociation in such patients. Also, symptoms such as dizziness
, decreased heartbeat, and fainting
may appear. The blood flow should be carefully monitored in such patients. Metoprolol should be discontinued if heart failure occurs or persists even after appropriate treatment. In the patients with congestive heart failure controlled by diuretics and digitalis, the Metoprolol should be used with caution.
Patients using adrenaline
The patients using adrenaline while treatment with Metoprolol are at an increased risk. These patients may develop an increase in blood pressure and a decrease in the heartbeat.
Patients with a history of psoriasis
Such patients with the history of psoriasis
are at increased risk while using this medicine. Metoprolol should be used with caution in such patients.
Patients with increased contractions in coronary arteries (variant angina pectoris).
Such patients are at increased risk when using this medicine. In these patients, beta blockers may raise the duration and number of angina
attacks. Proper care is required while using Metoprolol in these patients.
Patients with severe liver diseases
The patients with severe liver disease are at increased risk while using this medicine. The amount of Metoprolol in the blood is increased in such patients.
Patients with intravenous use of calcium
channel blockers while undergoing therapy with Metoprolol are at an increased risk. The combined use of calcium channel blockers and Metoprolol should be avoided.