As a commonly known emergency drug, nitroglycerin has contributed a lot, so what diseases is it used to treat and prevent? What are the precautions for using nitroglycerin, who can not use it, why its price suddenly skyrocketed, the correct use method is very important, otherwise there is no therapeutic significance! In this issue of popular science, we focus on it, please be sure to see the end, maybe bring you or your family and friends greater safety medication protection!
Nitroglycerin is available in 3 dosage forms: tablets and injections and sprays, tablets are mainly used to prevent and quickly relieve angina attacks caused by coronary artery disease, and nitroglycerin injection can also be used to lower blood pressure. Sprays aside!
Friends asked, what is the mechanism of nitroglycerin to lower blood pressure? Because nitroglycerin can dilate veins and selectively dilate coronary arteries, with large arteries, it lowers arterial pressure, although not as good as another old drug called nitroprusside, which is initially given intravenously at a rate of five to ten micrograms per minute.
Nitroglycerin injection has a rapid antihypertensive effect, and the effect disappears a few minutes after stopping the drug, and can be used to 100 to 200 micrograms per minute.
Nitroglycerin is a nitrate drug that can dilate coronary arteries, improve blood supply to the myocardium, and relieve angina symptoms. It can also dilate pulmonary veins, reduce cardiac preload, reduce myocardial oxygen consumption, improve myocardial perfusion, relieve angina, and treat congestive heart failure.
Nitroglycerin can be combined with B-blockers, such as lors, or with short-acting calcium antagonists, such as nifedipine, to relieve myocardial ischemia.
Nitroglycerin has a short half-life and is prone to drug resistance with repeated use, so it is not used as a long-term drug, but as a first-aid drug in the onset of angina pectoris in coronary heart disease and is used clinically. Specific use needs to be selected under the guidance of a doctor.
Notes
1. Patients with frequent attacks of angina pectoris can prevent attacks by taking it before stool.
2. Long-term use can produce tolerance.
3. During treatment, sildenafil should not be used. This point is why when nitroglycerin is combined with sildenafil citrate, a drug that inhibits PDE5 in vascular smooth muscle, the concentration of intracellular cGMP increases significantly, enhancing the relaxation of vascular smooth muscle, causing the risk of significant blood pressure drop, and eventually causing shock and even death in patients. This is an event with clinical data that shows that every year there are incidents where wrong medication leads to life safety issues! So everyone should keep this in mind!
4. The minimum dose that can effectively relieve acute angina should be used, overdose may lead to tolerance.
5. Severe hypotension may occur in small doses, especially in the upright position.
6. It should be used with caution in patients with hypovolemia or low systolic blood pressure. In the vernacular, people who have low blood pressure all year round and people who are anemic!
7. If blurred vision or dry mouth occurs, the drug should be discontinued.
8. When intravenous infusion of this product, because many plastic infusion sets can adsorb nitroglycerin, an infusion device that does not adsorb this product, such as a glass infusion set, should be used.
Correct use of nitroglycerin tablets: adults once with 0.25-0.5 mg (half a tablet - 1 tablet), sublingually. Repeat 1 tablet every 5 minutes until the pain is relieved. If the pain persists after a total of 3 tablets within 15 minutes, seek immediate medical attention.
Let's talk about the price of nitroglycerin, in fact, consumers in many parts of the country have reported that the most commonly used special drug for the treatment of angina has risen from a few yuan a bottle in the past to more than 50 yuan a bottle. Some insiders said that the raw material for the production of nitroglycerin tablets is nitroglycerin, and one of the raw materials for the preparation of nitroglycerin is nitric acid, nitric acid as a flammable and explosive product, suffered a large-scale reduction or suspension of production last year, resulting in the price of raw material nitroglycerin, so the price of nitroglycerin tablets has also risen with the water.
Experts said that cheap drugs, including nitroglycerin, have been maintained at a low level because of the previous maximum price limit, making it difficult for pharmaceutical companies to make profits, and some finished drug companies have gradually withdrawn from the market. Since June 2015, drug prices have been liberalized, so nitroglycerin is now subject to market-regulated prices. In July 2023, the price of nitroglycerin has fallen, although it is not the previous price, but the people can still accept the range price!
Who can't use nitroglycerin?
1. Those who are allergic to this drug or other nitrates are banned. The rashes produced by this drug, drug fever, exfoliative dermatitis, are all very common, not much to talk about!
2. Patients with early myocardial infarction (when there is severe hypotension and tachycardia) are banned. Nitroglycerin is banned in the early stage of myocardial infarction because patients with myocardial infarction will have clinical manifestations of hypotension in the early stage, and nitroglycerin can expand blood vessels and lead to a decrease in blood pressure, and the use of nitroglycerin can easily aggravate hypotension and even cause shock.
3. Patients with severe anemia are banned.
4. Patients with angle-closure glaucoma are banned. The reason why nitroglycerin cannot be used in angle-closure glaucoma is because the vasodilating effect of nitroglycerin can cause an acute large attack of angle-closure glaucoma, resulting in an increase in intraocular pressure. All vasodilator drugs have this effect, so glaucoma needs to be evaluated comprehensively before medication.
5. Patients with increased intracranial pressure are banned.
6. Patients using sildenafil and tadalafil are banned.
7. Patients with acute circulatory failure or shock are banned.
【Use with caution】
1. Patients with hypovolemia or low systolic blood pressure should be used with caution.
2. Patients with severe renal function impairment should be used with caution.
3. Patients with hypertrophic cardiomyopathy with left ventricular outflow tract obstruction should be used with caution.