During spring and summer, a wide variety of fruits come to market. Some people particularly enjoy eating sour fruits like lemons. However, if you are taking certain medications, it is best to pay attention to the acidity of fruits, as it may affect the efficacy of the drugs.
Enhancing the acidity of the digestive tract can increase side effects. The pH level of the digestive tract affects the degree of drug dissociation and absorption. When acidic foods, such as sour fruits, pass through, they change the gastrointestinal pH level, impacting drug absorption. Sulfonamide drugs have greater solubility in an alkaline environment, but in an acidic one, they can easily form crystals in the kidneys, damaging the renal tubules. Non-steroidal anti-inflammatory drugs (NSAIDs) like indomethacin and diclofenac can easily damage mucous membranes and cause bleeding. Sour fruits can exacerbate the irritation of these drugs on the gastric mucosa, and even induce gastric mucosal bleeding. An acidic environment can reduce the antibacterial activity of aminoglycoside antibiotics (such as gentamicin), affecting their efficacy; it can also slow down the excretion of aminoglycoside drugs, increasing their side effects, such as toxicity to the ears and kidneys.
Degrading drugs and affecting their onset. The mechanism of action for alkaline drugs like sodium bicarbonate, magnesium oxide, and compound aluminum hydroxide is based on acid-base neutralization. Eating sour fruits can easily degrade these alkaline drugs, affecting their efficacy. Digestive enzymes function well in an alkaline environment (the intestines) but are easily destroyed in an acidic one (gastric juice). These drugs are often coated with a substance (an enteric coating) to prevent them from dissolving in the stomach and allow them to dissolve and be absorbed in the intestines. However, it is generally not recommended to eat very sour fruits while taking such medications.
Unripe fruits can inhibit absorption. Some fruits are sour because they are unripe. These fruits contain more tannic acid, which inhibits gastrointestinal motility. Tannic acid can bind with metal ions in drugs, such as calcium, iron, and aluminum, to form precipitates. Tetracyclines and macrolide antibiotics (such as roxithromycin and azithromycin) may also bind with tannic acid, affecting their antibacterial activity.
Therefore, when taking the aforementioned medications, you should reduce your intake of sour fruits, and it is best to avoid eating them for 1-2 hours after taking the medication. You should take your medicine with plain water; it is generally not recommended to use fruit juice. Additionally, when taking drugs that are highly irritating to the gastrointestinal tract, you can take drugs to protect the gastric mucosa as directed by your doctor. Unless you have a specific condition like diabetes, you can choose sweeter, ripe fruits.