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Drug Class: Commonly Known As: Category:
Antibiotic Adult, Children

Antibiotics - Side Effects, Precautions, and Contraindications

What side effects can Antibiotics cause?

​Common side effects include:

  • Antibiotics taken by mouth may cause gastrointestinal side effects e.g. abdominal pain, nausea / vomiting and diarrhea. It is usually advisable to take the medication after food if you experience these side effects (unless the medicine label indicates that it must be taken on an empty stomach).
  • Antibiotics given by injections may cause local injection site reactions (pain, redness and swelling). These are usually mild and will go away within a few days.
  • Antibiotics applied topically to the skin may cause irritation, redness or dryness. When applied to the eyes, it may cause transient blurred vision, temporary stinging/burning/itching/irritation and increased sensitivity to light.

For more information on the side effects caused by specific antibiotics, please consult your doctor or pharmacist.

Antibiotics can sometimes increase the chance of fungal infections in the mouth (oral thrush) or vagina. This is because they kill off the "good" bacteria that help to control the overgrowth of fungi. Hence, the fungi can now grow to a larger number, causing an infection. Consult your doctor or pharmacist if you develop symptoms such as white patches on the tongue or white, curd-like vaginal discharge and itching.

There are some potentially serious, but rare side effects that may be experienced:

  • Severe watery and/or bloody diarrhea, fever and painful abdominal cramps. This can occur 1-2 days after you start taking an antibiotic, up to several weeks after you finish taking the antibiotic. This is due to overgrowth of the bacterium in the colon C. difficile.

Stop the medication immediately and seek medical attention if you experience the above or any severe allergic reactions like skin rash (with or without blisters, mouth ulcers, fever and itching), swelling of the eyes and lips or difficulty breathing

Before taking Antibiotics , what precautions must I follow?

Inform your doctor or pharmacist if you have any drug allergies, glucose-6-phosphate dehydrogenase (G6PD) deficiency, pregnant / breastfeeding or taking any other other medicines or herbal supplements before you start taking antibiotics. Alcohol should be avoided while taking certain antibiotics, such as metronidazole.


What food or medicine must I avoid when I take Antibiotics ?

Antibiotics - Additional Information

​​It is important to complete the course of antibiotic treatment as prescribed by the doctor and take the correct dose at the right time. Do not stop taking the antibiotic midway, even if you feel better. This is to prevent antibiotic resistance, which may lead to infections that are harder to treat in the future.

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