Drug name
Generic name: metoprolol tartrate tablets
English name: metoprolol tartrate tablets
Chinese Pinyin: Metoprolol 92 Acid "Two Tablets"
The main component of this product is metoprolol tartrate, and its chemical name is (RS) 1- isopropylamino -3-[ p -(2- methoxyethyl) phenoxy ]-2- propanol L(+)- tartrate.
Molecular formula: (c 15h25no3) 2 c4h6o6.
Molecular weight: 684.82
Characteristics This product is a white tablet.
Pharmacology and Toxicology The drug belongs to Class 2A, that is, β 1- receptor blocker (cardiac selective β-receptor blocker), and has no partial excitability. It has selective blocking effect on β 1- receptor, no PAA (partial excitability) and no membrane stabilization effect. Its blocking effect on β -receptor is similar to that of propranolol (PP), and its selectivity for β 1- receptor is slightly lower than that of atenolol. The effects of metoprolol on the heart, such as slowing heart rate, inhibiting myocardial contractility, reducing self-discipline and delaying atrioventricular conduction time, are similar to those of propranolol and atenolol (AT), and the effects of metoprolol on lowering elevated blood pressure and heart rate in exercise test are similar to those of PP and AT. Its contractile effect on vascular and bronchial smooth muscle is weaker than PP, so its influence on respiratory tract is smaller, but it is still stronger than at. Metoprolol can also reduce plasma renin activity. This product has no mutagenic effect; No effect on the fetus; Rats took this product for 2 years, and no benign or malignant new organisms were found at 800mg/ day.
Pharmacokinetics The fat solubility of metoprolol is between propranolol (PP) and atenolol (at). Oral absorption is rapid and complete, and the absorption rate is over 90%, but the liver metabolism rate is 95% and the first-pass effect is 25-60%, so the bioavailability is only 40-75%, which is similar to AT. The peak time of plasma concentration is generally 1.5 hours, and the maximum action time is 1-2 hours. The decrease of blood pressure is not parallel to the blood drug concentration, but the decrease of heart rate is linear with the blood drug concentration. The body distribution volume is 5.6L/kg, and the plasma protein binding rate is about 12\%, which can penetrate the blood-brain barrier and placenta, and can also be secreted by milk. Metoprolol t 1/2 lasted for 3-5 hours, and renal insufficiency did not change significantly. After renal excretion, the urine is mainly metabolites, and only 3- 10 \% is excreted through the kidney in its original form. Can't be excreted by dialysis.
Indications: hypertension, angina pectoris, myocardial infarction, hypertrophic cardiomyopathy, aortic dissection, arrhythmia, hyperthyroidism, cardiac neurosis and so on. It is still used in the treatment of heart failure in recent years and should be used under the guidance of experienced doctors.
Usage and Dosage Hypertension: once 1 00-200mg, twice a day, the curative effect is equivalent to atenolol100-200mg/time, once a day. It should be used immediately after the hemodynamics is stable. Stable angina pectoris: early use is also advocated, and the usage and dosage can refer to acute myocardial infarction. Metoprolol can be used intravenously when atrial fibrillation occurs in acute myocardial infarction, and the method is the same as above. If there are no contraindications, it should be used for a long time after myocardial infarction, because it has been proved that it can reduce heart mortality, including sudden death. Generally 50- 100mg/ time, twice a day.
Treatment of hypertension, angina pectoris, arrhythmia, hypertrophic cardiomyopathy, hyperthyroidism and other symptoms, generally 25-50m g/ time, 2-3 times a day, or 100mg/ time, twice a day. Heart failure: This drug should be used on the basis of anti-heart failure treatment such as digitalis and/or diuretics. At first, it was 6.25mg/ time, 2-3 times a day, and then it was increased by 6.25- 12.5mg/ time every few days to one week, 2-3 times a day, and the maximum dose was 50- 100mg/ time, twice a day. The maximum dose should not exceed 300-400 mg/day.
counteraction
1. Cardiovascular system: bradycardia, conduction block, decreased blood pressure, aggravation of heart failure, pulse impassability caused by limb coldness or peripheral vasospasm, Raynaud's syndrome.
2. Because of its fat solubility and easy penetration into the central nervous system, there are many adverse reactions in this system. Fatigue and dizziness accounted for 10%, depression accounted for 5%, and others were headache, dreaminess and insomnia. Occasionally I have hallucinations.
3. Digestive system: nausea, stomachache and constipation
4. Others: shortness of breath, joint pain, itching, retroperitoneal cavity fibrosis, deafness, eye pain, etc.
Hypotension and obvious bradycardia (heart rate 0.24 seconds or systolic blood pressure < 100 mmHg. It is forbidden for people who are allergic to any ingredients in this product.
Matters needing attention
1. Propranolol can delay the recovery of blood glucose level after insulin administration, but selective β 1- receptor blockers have fewer adverse reactions. It should be noted that the β receptor blocking effect of insulin-induced diabetic patients, when adding β receptor blockers, often masks the symptoms of hypoglycemia, such as palpitation, thus delaying the timely detection of hypoglycemia. However, selective β 1 receptor blockers are less likely to interfere with glucose metabolism or cover up hypoglycemia during treatment than non-selective β-receptor blockers.
2. If you want to stop using this product for a long time, you must gradually reduce the dose, usually within 7- 10 days, at least 3 days later. In particular, patients with coronary heart disease suddenly stop taking drugs, which will worsen their condition and lead to angina pectoris, myocardial infarction or ventricular tachycardia.
3. There is no consensus on whether to stop using β -blockers before major surgery. After β -blockers block, the heart's response to reflex excitation decreases, which increases the risk of general anesthesia and surgery, but it can be reversed by dobutamine or isoprenaline. Nevertheless, for patients who want to undergo general anesthesia, it is best to stop using this drug, if possible, 48 hours before anesthesia.
4.α receptor blockers should be used first in pheochromocytoma.
5. Use with caution when there is low blood pressure, abnormal heart or liver function.
6. Patients with chronic obstructive pulmonary disease and bronchial asthma should also be cautious if they need to use metoprolol, and it is advisable to use a small dose, which should generally be less than atenolol with the same curative effect. Patients with bronchial asthma should be given β2 receptor agonist at the same time, and the dose can be adjusted according to the dose of metoprolol.
7. Patients with cardiac decompensation should use metoprolol on the basis of digitalis and/or diuretics. For specific usage, see [Usage and Dosage].
8. It should not be used with verapamil to avoid bradycardia, hypotension and cardiac arrest.
9. Care should be taken when treating patients with insulin-dependent diabetes (IDDM).
The use of β -blockers by pregnant women and lactating women during pregnancy can lead to various fetal problems, including fetal growth retardation. Beta blockers can have adverse effects on fetuses and newborns, especially bradycardia, so they should not be used during pregnancy or delivery.
Children have limited experience in using this product.
The pharmacokinetics of elderly patients has no obvious change compared with young people, so the dose of elderly patients does not need to be adjusted.
Drug Interaction If patients take sympathetic ganglion blockers, other beta blockers (such as eye drops), or monoamine oxidase (MAO) inhibitors at the same time, the patient's condition must be closely monitored. Combined with reserpine, it can enhance the effect of this product and pay attention to hypotension and tachycardia. If you plan to terminate the combination with clonidine, you must pay attention to the fact that beta blockers should be stopped a few days earlier than clonidine. Metoprolol combined with verapamil and dihydropyridine calcium antagonists may increase negative muscle strength and chronotropic effect. Patients taking beta blockers should not be given verapamil calcium antagonists intravenously. Beta blockers can increase the negative inotropic effect and negative inotropic effect of antiarrhythmic drugs (quinidine and amiodarone). Inhalation anesthesia increases cardiac depression in patients treated with beta blockers. Enzyme-induced and enzyme-inhibited substances will affect the plasma level of metoprolol. Rifampicin can decrease the plasma concentration of metoprolol, while cimetidine, ethanol, hydralazine and selective serotonin reuptake inhibitors (SSRIs), such as paroxetine, fluoxetine and sertraline, can increase the plasma concentration of metoprolol. Using quinidine in advance can also increase the plasma concentration of metoprolol. Combined use of indomethacin or other prostaglandin synthase inhibitors will reduce the antihypertensive effect of β -blockers in some cases, patients who use β -blockers use epinephrine, and the influence of cardiac selective β -blockers on blood pressure control is far less than that of non-selective β -blockers For patients receiving beta blockers, the dosage of oral hypoglycemic agents must be adjusted.
Symptoms of drug overdose: Excessive metoprolol can lead to severe hypotension, sinus bradycardia, atrioventricular block, heart failure, cardiogenic shock, cardiac arrest, bronchospasm, unconsciousness/coma, nausea, vomiting and cyanosis. Taking alcohol, antihypertensive drugs, quinidine or barbiturates at the same time will aggravate the condition. The initial clinical manifestations of drug overdose will appear 20 minutes to 2 hours after taking the drug. Overtreatment: give activated carbon and gastric lavage if necessary. In the case of severe hypotension, bradycardia or impending heart failure, intravenous injection of β 1 receptor agonist (such as pretrol) or intravenous drip every 2-5 minutes until the expected effect is achieved. If there is no selective β 1 receptor agonist, dopamine or atropine sulfate (iv) can also be used to block the vagus nerve. If the curative effect is not satisfactory, other sympathomimetic amines such as dobutamine or norepinephrine can be used. Glucagon 1- 10 mg can also be given. You may need a pacemaker. Intravenous injection of β2 receptor agonist can relieve bronchospasm. The dose of antidote used to treat excessive β -blockers is much higher than the recommended dose in conventional treatment, because β -blockers are occupied by β -blockers Another case of acute poisoning was successfully treated with m-hydroxylamine after taking 200 tablets of 50mg/ tablet. The heart sound was weak and blood pressure could not be measured.
Specification 25 mg
Storage and shading, sealed preservation.
parcel
Shijiazhuang Yiling 10 tablets per board, 2 boards per box.
AstraZeneca dosage form packaging: specifications: 25mgx20 tablets; 50mgx20 tablets; 100mgx 10 tablets