Megapen 500mg Injection is a combination medicine that is used to treat various types of bacterial infections. It fights against the microorganisms to prevent their growth and further spread of the infection. Megapen 500mg Injection should only be administered under the supervision of a healthcare professional. Do not miss any scheduled appointments for taking this medicine. The course of the treatment must be completed even if you feel better. Sudden discontinuation of the treatment may affect the potency of the medicine.Some common side effects of this medicine are nausea, vomiting, diarrhea, indigestion, etc. If any of the side effects get aggravated, you must consult your doctor immediately. If you experience any allergic reaction (rashes, itching, swelling, shortness of breath, etc.), you must seek immediate medical help.Before taking this medicine, you should tell your doctor if you are taking any medicines for any health condition. Pregnant or breastfeeding women should also consult with their doctor before taking it. Avoid drinking alcohol as it can cause excessive drowsiness with this medicine. It usually does not impair your ability to drive, but you should not drive if it makes you feel sleepy or dizzy. You must take adequate rest for a faster recovery, also take a healthy diet and drink plenty of water. Your doctor may ask for a few laboratory and diagnostic tests to know the effects of the medicine on your body.