Some physiological functions or pathological phenomena of human body show obvious circadian rhythm. Modern medical research has confirmed that the effects and toxicity of many drugs, adverse reactions and human biological rhythms have an extremely close relationship. The same drug in the same dose can have different effects and efficacy depending on the time of administration. According to the pharmacology of time, choose the most suitable time to take drugs, you can achieve twice the result with half the effort. The following is a summary of the time of administration of various drugs. Hypertension In humans, there are obvious diurnal fluctuations in blood pressure. It rises sharply in the morning from 9:00-11:00 a.m. and is at a higher level during the day, then rises again from 4:00-6:00 p.m., and then falls slowly, reaching a minimum at 3:00 a.m., and starts to rise again in the morning before waking up. Therefore, the incidence of cardiovascular and cerebrovascular diseases is higher in the morning. Generally, a decrease of ≥ 10%-20% in blood pressure at night compared to daytime blood pressure indicates a normal circadian rhythm, with a bimodal peak and a valley type, called “aryepiglottic blood pressure”. If the tendency of blood pressure to fall at night becomes smaller and the blood pressure curve tends to level off throughout the day, a decrease of <10% at night indicates an abnormal circadian rhythm, which is called "non-adventurous blood pressure". 1, arytenoid blood pressure 7:00 a.m. and 14:00 p.m. twice is appropriate, so that the peak time of drug action coincides with the two peaks of natural blood fluctuations, the best effect of lowering blood pressure at this time. It should not be taken at bedtime or at night to avoid ischemic stroke caused by low blood pressure during sleep at night, especially in the elderly. 2. Non-arrythmic blood pressure, however, should be taken at night before bedtime. Calcium channel blockers and ARBs taken in the morning or in the evening have the same effect on 24-h mean blood pressure, but those taken in the evening are more effective in lowering the nighttime mean blood pressure, which in turn helps to convert the non-aspirate blood pressure to the arytenoid blood pressure. Diabetes mellitus The pancreatic islet β-cells secrete about 50 IU of insulin daily, and its secretion has a rhythm, starting to rise in the early morning, peaking in the afternoon and dropping to a low in the early morning. Therefore, a low dose of insulin given early in the morning can achieve satisfactory results. At 8:00 a.m., strong and long-lasting hypoglycemic drugs can be taken orally, so that the effect of the drug can be adapted to the law of blood glucose concentration changes in the body. For example, the 0.5h blood glucose drop after methanesulfonylurea at 8:00 am is significantly greater than that of those given at 18:00 am. Sulfonylurea hypoglycemic drug (glibenclamide): it produces hypoglycemic effect by stimulating pancreatic islet cells, and it takes some time to work after oral administration, so it is appropriate to take it 30 minutes before meal. Biguanide hypoglycemic agents (metformin): These drugs have a hypoglycemic effect by promoting the use of glucose in peripheral tissues such as muscles, so they should be taken after meals. Glucosidase inhibitors (Acarbose ): etc. competitively inhibit glucoside hydrolase in the small intestine, so that the increase in blood glucose after meals is reduced, and therefore, the therapeutic effect can only be produced if taken at the same time as eating. Ischemic heart disease Myocardial ischemia, ventricular arrhythmias, acute angina pectoris and sudden cardiac death all have peak episodes between 6:00 a.m. and 12:00 p.m. Therefore, the anti-platelet aspirin is more bioavailable in the morning, has a longer half-life, and is more useful in preventing cardiovascular events. Rheumatoid arthritis Patients with rheumatoid arthritis have symptoms such as joint swelling, stiffness and decreased grip strength, which are most severe in the morning; and the secretion rhythm of glucocorticoids shows circadian rhythmic changes, with peak blood concentration generally at 7-8 am and trough at 0 midnight. Therefore, it is best to take hormone drugs in the morning. Short-acting glucocorticoids, such as cortisone and hydrocortisone, are administered once a day. Long-acting glucocorticosteroids, such as prednisone, should be given once every other day. Anti-cancer treatment Tumor cells grow and multiply fastest at 10:00 a.m., while normal cells grow fastest in the early morning, so the best time for tumor patients to take the drug is 10:00 a.m.. Chemotherapy at this time is the most economical, the most effective and the least adverse effects. For cancer patients with severe pain in the late stage, there is also a rule for using painkillers; human pain sensation is most sluggish in the morning and most sensitive from midnight to early morning, so painkillers are more effective when taken at night before going to bed. Asthma Because of the physiological diurnal fluctuations of adrenocorticotropic hormone, catecholamine secretion level and ciliary movement of respiratory mucous membrane epithelial cells, asthma attacks mostly in the late night or early morning. Therefore, most asthma medications are best taken at bedtime, when asthmatics are most sensitive to acetylcholine and histamine. β-agonists such as terbutaline can be administered in a low morning and high night dosing method: 5 mg orally at 8:00 a.m. and 10 mg orally at 20:00 p.m. This can keep the blood concentration of the drug relatively stable around the clock and maintain a higher blood concentration in the early morning when the airway resistance increases. Unlike aminophylline, whose therapeutic and toxic doses are close to each other, it is most effective and least toxic when taken around 7:00 am. Iron deficiency anemia Iron deficiency anemia requires iron supplements such as iron gluconate and ferrous iron, which can be irritating to the gastrointestinal tract and must be absorbed under the action of gastric acid. Therefore, it is advisable to use them at the time when stomach acid secretion is the most active, and stomach acid secretion is the highest in the evening, so it is best to take them at 20:00 p.m. The absorption rate is higher than 8:00 a.m., and the efficacy is 3-4 times longer. The secretion of gastric acid has a diurnal pattern, with the lowest secretion from 5:00 am to 11:00 noon and from 2:00 pm to 1:00 am the next day, so the abdominal pain symptoms of gastric ulcer mostly occur at night. Cimetidine (H2 receptor blocker): fast absorption on an empty stomach; inhibition of gastric acid secretion occurs early and overlaps with the neutralization of gastric acid by food; change to an all-day dose to be taken at bedtime. Compound aluminum hydroxide tablets: gastric mucosa protector should be taken 30 min before meals to facilitate antacid, absorption and protection of ulcer surface. Omeprazole (proton pump inhibitor): The phenomenon of "nocturnal acid breakthrough" can be overcome by taking it at bedtime.