Comparison of the plasma pharmacokinetics and renal clearance of didanosine during once and twice daily dosing in HIV-1 infected individuals.
OBJECTIVE
To compare the plasma pharmacokinetics of didanosine during once daily (qd) and twice daily (bid) dosing.


METHODS
Open-label, randomized, cross-over study.


METHODS
HIV-1 infected patients who used didanosine were randomized to either a qd or a bid dosing regimen of didanosine. The total daily dose of didanosine was identical in both regimens. Seven days after the start of the study, the pharmacokinetic profile of didanosine in plasma and urine was assessed during an 8-h period. The next day, the patient was switched to the opposite dosing regimen, and after another 7 days, the study was concluded by again assessing the plasma and urine pharmacokinetics of didanosine during 8 h.


RESULTS
A total of 19 patients completed the study. The pharmacokinetics of didanosine in plasma (with maximum plasma concentration adjusted for dose) and urine were not significantly different in the qd and bid dosing regimen (P > 0.28 for all parameters).


CONCLUSIONS
We conclude that qd dosing of didanosine leads to a similar exposure in plasma as bid dosing (using the same total daily dose). Since qd dosing may lead to improved compliance of patients to regimens containing didanosine, these results provide a rationale for prescribing didanosine in a qd regimen, and is reassuring when we realize that the drug is being administered in a qd dosing regimen on a large scale in clinical practice.
Hoetelmans
R M
RM
Department of Pharmacy & Pharmacology, Slotervaart Hospital, Amsterdam, The Netherlands.
van Heeswijk
R P
RP
Profijt
M
M
Mulder
J W
JW
Meenhorst
P L
PL
Lange
J M
JM
Reiss
P
P
Beijnen
J H
JH
D000328:Adult; D018592:Cross-Over Studies; D016049:Didanosine / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics* / Q000652:urine; D004334:Drug Administration Schedule; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000652:urine; D015497:HIV-1; D006801:Humans; D008297:Male; D008875:Middle Aged; D015394:Molecular Structure
D016049:Didanosine