Learn about Zostum O uses, dosage, side effects, food interactions, and more. Get all the details about Zostum O from MedicinesFAQ. Zostum-O 200mg Tablet is an antibiotic which kills the harmful bacteria, but it can also affect the helpful bacteria in your stomach or intestine and cause diarrhea. Buy Zostum-O 200 Tablet Online. Know uses, side effects, dosage, contraindications, substitutes, benefit, interactions, purpose, drug interactions, precautions, warnings etc. Download Practo app & get your medicines home delivered. Zostum-O Tablet is used to treat bacterial infections. It contains Cefditoren which works by inhibiting the growth of infection-causing bacteria. In some cases, this medicine may cause side effects such as indigestion, diarrhoea, stomach pain and nausea.