Should antibiotics be taken before or after meals?

In case of inflammation in the body, antibiotics are required to be taken. Different antibiotics target different bacteria. Commonly known antibiotics include penicillin, cephalosporin, and erythromycin. Both the timing and dosage of antibiotics are crucial. Whether antibiotics should be taken before or after meals depends on the specific drug. For instance, regular erythromycin can be taken within two hours after meals. Many people experience gastrointestinal symptoms such as nausea, vomiting, and upper abdominal discomfort as common adverse reactions to erythromycin. The higher the dose of erythromycin, the greater the likelihood of gastrointestinal reactions. On the other hand, erythromycin has the issue of widespread distribution and low blood concentration. To achieve the goal of inhibiting bacterial growth, it is necessary to increase the blood concentration of erythromycin as much as possible. Generally, food can reduce the absorption of drugs. Therefore, to obtain a higher blood concentration and enhance the efficacy of erythromycin, except for esters (such as erythromycin estolate and erythromycin ethylsuccinate), erythromycin should be taken on an empty stomach with water. Whether to take it on an empty stomach also depends on the dosage form. Regular erythromycin tablets can be taken 2 hours after meals, when there is a small amount of food left in the stomach. This allows erythromycin to be partially diluted, reducing irritation to the gastric mucosa while enabling faster absorption in the small intestine. Additionally, this avoids the decreased effectiveness due to excessive breakdown in the stomach after a meal. Erythromycin enteric-coated tablets are recommended to be taken on an empty stomach. Under normal conditions (normal gastric motility and emptying), the enteric-coated tablets will not dissolve in the acidic environment of gastric juice but will only start to dissolve and absorb in the alkaline intestinal juice. Therefore, there is no issue of dissolution in the stomach and gastric motility abnormalities with erythromycin enteric-coated tablets. It is important to note that taking antibiotics three times a day does not mean taking them after each meal, which is a common misconception. Taking drugs along with meals can affect their absorption and result in uneven blood concentration changes, with high concentrations after meals and reduced concentrations after the third dose, especially at night, affecting the therapeutic effect.