The potential for a clinically detrimental interaction between didanosine and tenofovir disoproxil fumarate (DF) has received considerable attention lately in the medical community. Tenofovir DF is a nucleotide analog of adenosine 5’-monophosphate, which was approved by the Food and Drug Administration (FDA) for the treatment of human immunodeficiency virus (HIV) infection in October 2001. Didanosine, 1 of 7 nucleoside reverse transcriptase inhibitors (NRTIs) marketed in the United States, has been implicated as the causative agent significant adverse events such as lactic acidosis/hepatic steatosis, pancreatitis, and peripheral neuropathy.