A case of under-dosing after raltegravir formulation change in an elderly patient treated for HIV

Our case was a 70-year-old male (height: 168 cm, weight: 74.3 kg) with polypharmacy (total 15 drugs including 10 tablets) who was treated for HIV infection. His dosing schedule of raltegravir was changed from BID (a 400 mg tablet, twice) to QD (2x600 mg tablet, once). After a month, we found that he miss-took raltegravir for 1x600 mg tablet at once. His HIV-1 RNA increased from undetectable levels to < 20 copies per mL. Pharmaceutical companies should therefore carefully consider swallowing difficulties in old patients, such as by reformulating medications so that only one dosing is required per day and decreasing the size of tablets to 7-8 mm in diameter or orally distinguish tablet.