What is Amoxicillin? Uses, dosage and contraindications

The article was written by Pharmacist Cao Thanh Tu - Faculty of Pharmacy - Vinmec Times City International General Hospital

Amoxicillin is an antibiotic that kills certain types of bacteria and has no effect on viruses. So in what cases is the drug used, how does it work, and how is it used?

Amoxicillin is an antibiotic in the penicillin group that is effective against certain types of bacteria. Therefore, Amoxicillin is used to treat infections caused by these bacteria. Your doctor may also prescribe Amoxicillin to prevent certain infections if you are at risk for these infections. The drug does not work for viral infections (eg colds or flu....) and also only works on certain types of bacteria, so it can be effective in this infection without effective against other infections.
Moreover, bacteria are always trying to adapt to the effects of antibiotics, making many antibiotics that work well now become ineffective (antibiotic resistance). Therefore, the decision whether to use antibiotics or not and which antibiotic to choose requires appropriate examination and evaluation of the doctor, should not be arbitrarily used according to the old prescription or the patient's prescription. other patients with similar symptoms.

Do not use the drug in patients who have ever had a severe allergic reaction to Amoxicillin or other antibiotics of the same class or to any of its ingredients. Amoxicillin should also not be used in patients with infectious mononucleosis (a viral illness, common symptoms are fatigue, fever, sore throat, and swollen lymph nodes in the neck) because some patients have may be more likely to experience drug-induced skin reactions (such as rash).
Because the drug is eliminated from the body mainly through the urine, it should be used with caution in patients with impaired renal function. In some cases, it may be necessary to reduce the dose or increase the interval between doses to avoid drug accumulation in the body causing toxicity.

Amoxicillin dosage depends on many factors (age, weight of the patient, dosage form of the drug, renal clearance and severity of infection)
In general, the usual dose in humans 500 mg - 1000 mg/time x 2 - 3 times/day. For children, the dose is usually calculated by weight. Dosage for mild infections, average is 25-50 mg/kg/day divided into 2-3 times a day. In some severe infections, the dose may be increased to 80-100 mg/kg/day
For patients with impaired renal elimination, the dose of Amoxicillin may be reduced to a lower dose. normally or even without the use of certain dosage forms.
Amoxicillin can be taken with or without food. The extended-release tablet form should be taken within one hour of a meal. Taking the drug with food may reduce gastrointestinal side effects (nausea, vomiting). Should be evenly spaced between doses (eg, every 8 hours if used 3 times / day or every 12 hours if used 2 times / day) for the drug to have the best antibacterial effect.

Depending on the dosage form, the way the drug is used can be different. For example, the suspension form usually requires pre-mixing and shaking before use, and the extended-release tablet form must be swallowed whole, without chewing, breaking, or crushing. Liquid medicine requires an accurate dosing device and can only be used for a certain time after mixing. Refer to the information in the package insert or consult your pharmacist for the correct use of each dosage form.

In general, Amoxicillin causes few side effects. Common side effects of the drug are nausea, vomiting, diarrhea. These side effects are usually mild and go away on their own. However, if the side effects persist, especially severe diarrhea, many times a day, diarrhea with blood, it is necessary to notify the doctor.
Some patients may experience a serious allergic reaction to Amoxicillin, so when you see any signs of an allergic reaction (such as itching, rash, swelling of the eyes, mouth, difficulty breathing, etc.), need to stop taking the drug and see a doctor for timely diagnosis and treatment.
Tell your doctor about any medications you are taking including herbs and supplements.
Do not arbitrarily stop the drug when the symptoms have improved, must take the medicine for the full number of days prescribed. This helps prevent the infection from re-growing and reduces the risk of resistance in future uses. If symptoms do not improve with medication, consult your doctor.
In case you forget to take your medicine, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take your next dose as usual. Do not take a double dose to make up for a missed dose.

Although Amoxicillin has not been shown to cause harm to a baby, always tell your doctor before taking any medicine if you are pregnant, planning to become pregnant or breast-feeding.
For any questions or concerns about this drug, you can contact the hotline of Vinmec International General Hospital. This is a prestigious medical facility, with a team of experienced, highly qualified doctors and nurses with academic degrees and high degrees in the industry. Here, not only gathers a team of famous domestic doctors but also international doctors, bringing the most effective and new treatment regimens today.
Modern medical equipment system, fully equipped, comfortable facilities, clean environment, meeting the strict requirements of the Ministry of Health to help patients feel secure during treatment. To register for examination and treatment at Vinmec International General Hospital, you can contact the nationwide Vinmec Health System Hotline, or register online HERE.