Niacin and its Derivatives:
These types of drugs may be associated with inhibiting the breakdown of adipose tissue and reducing the synthesis and secretion of very low-density lipoprotein in the liver, resulting in decreased levels of cholesterol, triglycerides, and low-density lipoprotein. Niacin can also increase the levels of high-density lipoprotein, although the mechanism is unclear. Acipimox, which has a similar structure and action to niacin, has no toxic side effects associated with niacin and is 20 times more effective in lowering lipid levels.
(1)Niacin
- [Action] The therapeutic efficacy and dosage of niacin in regulating blood lipids depend on the pre-treatment lipid levels. Oral doses of 3-6 grams per day of niacin result in a decrease in triglycerides after 3-4 days, a decrease in LDL-C after 5-7 days, and a decrease in total cholesterol of 10%-35%, LDL-C of 15%-33%, and triglycerides of 20%-40% after 5-7 days. HDL-C levels may increase by approximately 33% to a mild to moderate extent. The maximum therapeutic effect occurs in the 3rd to 5th week. Co-administration of niacin with bile acid sequestrants can enhance the cholesterol-lowering effect, and long-term treatment can lead to regression of xanthomas.
- [Dosage] Oral administration, 3 times daily, 1-2 grams per dose. To reduce adverse reactions after starting treatment, the initial dosage can be divided into 4 doses per day, with each dose ranging from 0.1 to 0.5 grams. The dosage can be gradually increased to 3 times per day, 1-2 grams per dose.
- [Adverse reactions]
- a. Niacin can cause intense flushing and itching of the skin, which many patients may find intolerable. However, if treatment is continued for several weeks, this reaction tends to diminish or disappear in most patients (taking niacin after meals, avoiding drinking vegetable soup during meals, drinking less water before taking niacin, or taking 300 milligrams of aspirin before niacin to alleviate flushing symptoms).
- b. Niacin enhances the vasodilatory effect of antihypertensive drugs and can even cause orthostatic hypotension.
- c. Niacin reduces glucose tolerance and worsens diabetes.
- d. In severe cases, it can exacerbate peptic ulcers.
- e. Rare cases of liver dysfunction, increased serum transaminase and alkaline phosphatase activity, and even cholestatic jaundice have been reported. In such cases, the medication should be discontinued promptly, and recovery is usually observed after discontinuation.
- [Precautions]
- a. Regular monitoring of liver function, blood glucose, and uric acid levels should be performed during medication. If significant abnormalities occur, the dosage should be promptly reduced or discontinued.
- b. Caution should be exercised in patients with peptic ulcers, impaired liver function, hypertension, and diabetes. Niacin should not be taken by pregnant or lactating women.
(2)Acipimox
- [Action] Acipimox is a derivative of niacin that significantly lowers triglyceride and cholesterol levels. It also increases HDL-C levels. Acipimox can promote glucose metabolism in non-insulin-dependent diabetic patients and enhance glucose absorption.
- [Dosage] Oral administration, 3 times daily, 0.25 grams per dose, taken after meals.
- [Adverse reactions] After the initial dose, flushing, warmth, and itching of the skin may occur, which usually disappear after a few days. Occasionally, gastrointestinal reactions, headache, and fatigue may occur.
- [Precautions] Caution should be exercised in pregnant or lactating women, and acipimox should be avoided in patients with peptic ulcers. Patients with renal insufficiency should take a reduced dosage.