Cefdinir achieves a top degree inside the blood within two to four days of taking a dental pill. 7 In case you are having aluminum or magnesium-containing antacids, metal pills, or multivitamins, never take them at exactly the same time which you just take this medicine. It is advisable to capture these medications at the very least 2 hours before or after getting cefdinir. These drugs may keep cefdinir from functioning properly the length of time does it get for omnicef (cefdinir) to focus for an ear issues for a 3 year old? Dr. Linda Gromko replied 48 ages knowledge family members Medicine 24-48 hrs to begin: it’s my job to count on the majority of antibiotics to begin to capture keep within 24-48 hours exactly how should this drug be applied?