Cefdinir is used to treat bacterial infections, according to the National Institutes of Health. This includes sinusitis, skin infections, tonsillitis and strep throat.
The medication works by inhibiting the growth of bacteria in the body that is causing the infection, as stated by WebMD. Only a doctor can prescribe the medication and people using it should follow the directions carefully. It comes in liquid or capsule form and the dosage varies depending on the condition it is treating and the age of the patient. The medication can cause side effects, such as upset stomach, dizziness, vomiting, loss of appetite and fatigue.