When elderly people take amlodipine, the half-life may be 50 hours. Can they take it once every two days?

An elderly friend told Huazi that he had seen an article saying that the half-life of amlodipine is very long, normally more than 36 hours. For the elderly, due to decreased metabolic function, the half-life of amlodipine may exceed 50 hours. Since the half-life is so long, can the elderly take amlodipine once every two days?

Huazi said that amlodipine cannot be taken once every two days. Because in antihypertensive treatment, blood pressure should not only be lowered, but also kept stable. If amlodipine is taken once every two days, it will cause a large fluctuation in blood drug concentration, which may cause a large fluctuation in blood pressure and the risk of inducing cardiovascular and cerebrovascular diseases.

1. Long-acting dihydropyridine drugs Amlodipine is a dihydropyridine antihypertensive drug, also known as a dihydropyridine calcium channel antagonist (CCB), which can bind to calcium channel proteins on the membrane of vascular smooth muscle cells to inhibit calcium ions from entering cells. Calcium ions can excite smooth muscle cells, causing blood vessels to contract and blood pressure to rise. Dihydropyridine drugs close the "gate" for calcium ions to enter cells, which will cause blood vessels to dilate and blood pressure to drop.

Amlodipine is a long-acting dihydrochloride drug. Its oral administration is not affected by diet. It takes about 6 to 8 hours to reach the peak blood concentration after oral administration. It is metabolized by the liver with a half-life of more than 36 hours, making it a long-acting dihydrochloride drug. For people with poor liver function and the elderly, the half-life may exceed 50 hours.

2. The half-life of a drug is not the interval between taking the drug. The meaning of the half-life of a drug refers to the time required for the blood concentration of the drug to drop by half. Generally speaking, the longer the half-life, the longer the drug effect lasts. People with high blood pressure are suitable for long-acting antihypertensive drugs, because long-acting antihypertensive drugs can control blood pressure more steadily.

However, the half-life of a drug is not the interval between medications. During antihypertensive treatment, blood drug concentrations should be kept as stable as possible. In theory, the smaller the dose and the higher the frequency of medication, the more stable the antihypertensive effect will be. However, increasing the frequency of medication will affect the patient's medication compliance, so the common choice is to take long-acting antihypertensive drugs at a frequency of once a day.

3. Continue to take the medicine for more than 10 days to see the effect. The half-life of amlodipine is very long. Only by taking a small dose every day can the accumulation reach the "plateau value" required for the therapeutic dose. This process requires continuous medication for 7 to 10 days. In the initial stage of using amlodipine, it is normal to have blood pressure fluctuations. It takes 10 days to achieve the best blood pressure lowering effect.

Taking a small dose of the drug every day can reduce the peak height and peak-to-valley difference of the blood drug concentration, while steadily lowering blood pressure, making it easier for the body to tolerate and less likely to produce adverse reactions such as facial flushing and tachycardia. In other words, taking the drug once a day is safer than taking it once every two days.

4. Levoamlodipine has fewer adverse reactions. Amlodipine contains two isomers, one is levoamlodipine and the other is dexamlodipine. The antihypertensive effect of the former is more than 1,000 times that of the latter, and the effect lasts longer and has fewer adverse reactions. If the adverse reactions of using amlodipine are too severe, you can consider switching to levoamlodipine.

However, the protective effect of amlodipine on cardiovascular system is slightly stronger than that of levoamlodipine, so when choosing medication, amlodipine is usually chosen first. It should be noted that the dose of levoamlodipine is half of that of amlodipine. For example, 5mg of amlodipine is as effective as 2.5mg of levoamlodipine. Do not take an overdose.

To sum up, although the half-life of amlodipine is very long, even up to 50 hours for elderly patients, the half-life of the drug is not equivalent to the interval between medications. In order to maintain blood pressure stability, long-acting antihypertensive drugs also need to be taken daily and cannot be changed to once every two days. If you have any questions about medication, you can consult a doctor or pharmacist. I am pharmacist Huazi, welcome to follow me,