Erratic absorption of intramuscular antimicrobial delivery in infants and children

In the absence of intravenous or enteral access, an intramuscular (IM) injection of medications is a viable alternative. Vaccines, antibiotics and analgesics are commonly administered by this route in pediatric medicine to enhance adherence to regimens. Although it is expected that the entire dose be administered by the IM route, the absorption (rate and extent) of the medication from the muscle tissue into systemic circulation can be erratic and depends on the drug's physicochemical factors and patient-specific factors. Despite the variability in absorption, administration of medications by the IM route may be considered when medications do not need to attain maximal concentrations rapidly. IM injections are generally well-tolerated, but potential injury to the injected muscle and the proximal nerves should be recognized.