Introduction
Metoprolol tartrate is a white or almost white crystalline powder with the chemical name (±)-1-(isopropylamino)-3-[p-(2-methoxyethyl) phenoxy]-2-propanol (+)-tartrate (2:1). It is a selective β1 receptor blocker used in the treatment of hypertension, angina pectoris, myocardial infarction, hypertrophic cardiomyopathy, aortic dissection, cardiac arrhythmia, hyperthyroidism, and other diseases. Of these, it is most commonly used to treat hypertension. The structure of metoprolol tartrate is shown in fig. 1.
Fig. 1 Structure of metoprolol tartrate
Application in the treatment of hypertension
- Introduction of hypertension
Hypertension is characterized by persistently high blood pressure in the systemic arteries, which is associated with an increased risk of cardiovascular disease (CVD). It is the most important modifiable risk factor for all-cause morbidity and mortality worldwide. Hypertension is classified as primary hypertension and secondary hypertension. About 90-95% of patients are primary hypertension that caused by nonspecific lifestyles and genetic factors. Nonspecific lifestyles include obesity, smoking, drinking, lack of exercise and excess salt in the diet, which provide us with measures to prevent hypertension. In addition, the regulation of blood pressure is related to many neuroendocrine systems, which provide us with a breakthrough to treat hypertension. Fig. 2 shows the major neuroendocrine systems involved in the regulation of blood pressure.
- Mechanism of action
Activated β1 receptors cause the elevation of blood pressure. Metoprolol tartrate is a β1 receptor inhibitor that competitively blocks β1 receptors with minimal or no effects on β2 receptors. This inhibition decreases myocardial contractility and slows down heart rate, leading to the reduction of cardiac output, thereby lowering blood pressure. In this process, metoprolol tartrate does not exhibit membrane stabilizing or intrinsic sympathomimetic activity.
- Side effects
Common side effects of metoprolol tartrate mainly include:
Sweating
Shortness of breath
Unusual tiredness or weakness
Confusion
Chest pain or discomfort
Blurred vision
Slow or irregular heartbeat
Less common side effects of metoprolol tartrate mainly include:
Cough
Night blindness
Rapid weight gain
Decreased urine output
Loss of vision
Extreme fatigue
Disturbed color perception
Dilated neck vein
Mental confusion
Short-term memory loss
Rare side effects of metoprolol tartrate mainly include:
Clay-colored stool
Unpleasant breath odor
Continuing loss of appetite
Numbness of the fingers or toes
Continuing or severe nausea
Upper right abdominal or stomach pain