There was a female patient, 50 years old, with a history of kidney stones, who was given calcium carbonate tablets calcium supplementation and other treatments for "postmenopausal osteoporosis", but after half a year, the patient's kidney stones increased significantly compared with before.
In addition, there are also grassroots pharmacists who ask me for advice: I have a lot of doubts about calcium supplement medication, such as calcium carbonate tablets in what time is best to take? After reviewing the information, it was found that there were many opinions on the recommendations for taking it in the morning, at night, and before going to bed, and its drug instructions were not clearly stipulated; for example, whether calcium was taken before and after meals...
In this regard, I would like to elaborate from the following three aspects.
01
First, clarify the reasons for calcium supplementation
Calcium is an important mineral of the human body, of which 99% is present in bones and teeth, calcium ions and phosphorus constitute hydroxyphosphate lime crystals that settle on the matrix composed of collagen, maintaining the firmness of bone, and the remaining 1% is distributed in blood, nerves and various soft tissues.
When the body is deficient in calcium, on the one hand, bone metabolism is converted to bone lysis due to the lack of raw materials that make up bone; on the other hand, the decline of blood calcium to the threshold will lead to hypersecretion of parathyroid glands (parathyroid hormone can increase blood calcium), increase bone resorption, and make calcium free from bone tissue into the blood;
Both of these factors can lead to a decrease in bone mass per unit volume, so calcium deficiency is one of the important causes of osteoporosis. Therefore, whether it is primary osteoporosis (including postmenopausal and senile calcium deficiency) or osteoporosis secondary to other diseases or drugs, appropriate calcium supplementation is necessary to maintain health.
02
Second, how to choose calcium agents
There are many varieties of calcium agents, according to their components can be divided into: inorganic calcium, organic calcium, active calcium, new calcium preparations, etc., the role characteristics and selection of various types of calcium agents, can refer to the attached table.
1. The general population often uses inorganic calcium with high calcium content, such as calcium carbonate. However, people who lack stomach acid basically do not absorb inorganic calcium, while the elderly often have reduced gastric acid secretion, so it is recommended that people older than 65 years old and with gastric acid deficiency take calcium citrate and other organic acids.
2. Patients with hypoparathyroidism and chronic renal failure often have hyperphosphatemia, so phosphorus-containing calcium agents (dibasic calcium phosphate) cannot be selected, calcium carbonate, calcium citrate, calcium acetate should be selected, which can be used as calcium supplementation and phosphorus binder for hyperphosphatemia to reduce blood phosphorus concentration. It should be noted that calcium citrate can increase intestinal aluminum absorption, which is contraindicated in those who take aluminum agents; calcium gluconate is not suitable for diabetic patients.
3. What about stone patients as mentioned earlier in this article? Long-term use of general calcium agents such as calcium carbonate, will cause increased blood calcium and urine calcium concentrations, and then increase the risk of urinary tract oxalate crystallization, stone formation, especially in patients with a history of urinary system stones.
In this regard, the clinic recommends that patients with such stones use calcium citrate when supplementing calcium. Because calcium citrate has a strong complexation of calcium, when increasing the concentration of citric acid, it can be combined with the replacement of calcium oxalate, free calcium ions and calcium phosphate salts, etc., thereby forming a complex that is easily soluble in water, inhibiting the precipitation of calcium ions in supersaturated state and forming stones.
03
Second, the dosage and method of taking
1. Dosage
The Nutrition Society of China has formulated a recommended daily calcium intake of 800mg for adults, which is the appropriate dose to obtain the ideal bone peak and maintain bone health; while for postmenopausal women and the elderly, the recommended daily calcium intake is 1000mg. The current dietary nutrition survey shows that the average daily calcium obtained by the elderly in China is about 400mg, so the average daily amount of elemental calcium that postmenopausal women and the elderly should supplement is 500 to 600mg (such as each tablet of calcium carbonate contains 600mg of elemental calcium).
And during calcium supplementation, blood calcium and urine calcium concentrations should be detected every 3 months, and the drug should be discontinued if hypercalcemia occurs; if urinary calcium is increased, the calcium dose should be reduced.
2. How to take it
(1) Take in divided doses
The absorption rate of taking in divided doses is better than that of a large dose, and it is generally recommended to take 1 time in the morning and 1 time in the morning, or 3 to 4 times a day.
(2) Take with food
Since the acidic environment is more conducive to the absorption of commonly used calcium carbonate, and food stimulation can increase the secretion of gastric acid and improve the absorption efficiency of calcium, it is recommended that calcium carbonate be taken with food.
However, care should be taken to avoid taking vegetables with spinach, amaranth and other vegetables containing more oxalic acid, because oxalic acid can reduce calcium absorption and increase insoluble calcium salt production. Organic calcium acid and biocalcium do not need to be activated by stomach acid and do not have to be taken with food.
(3) Take it in combination with vitamin D
Vitamin D can promote the absorption of calcium, China's relevant guidelines recommend that ordinary vitamin D for the treatment of osteoporosis, the dose can be 800 ~ 1200 IU / day.
Since ordinary vitamin D can only work if it is converted into active vitamin D, it can also be replaced by active vitamin D, such as α-calcitriol 0.25 to 1.0 μg per day, or calcitriol 0.25 to 0.5 μg per day. Note that patients with osteoporosis secondary to renal failure can only supplement with calcitriol, because α-calcitriol requires renal 1-α hydroxylase activation, while renal 1-α hydroxylase levels in patients with renal failure have been reduced.
Signed author Wang Shuping
Chief pharmacist of the Department of Pharmacy of Huanggang Central Hospital in Hubei Province
Member of the Expert Committee on Health Science Popularization in China
Member of the Expert Steering Committee of Pharmaceutical Knowledge Management (MKM) of China Health Promotion Foundation
He has been engaged in hospital pharmacy for more than 40 years, specializing in hospital pharmacy management, hospital preparation, clinical drug consultation, etc.; he has edited 8 pharmaceutical monographs and won many national, provincial and municipal science and technology progress awards. In recent years, he has published more than 400 articles on pharmacy and popular science in newspapers and magazines.