Reminder series App

Hey guys,

Is there an app in appstore which I can use to give me this kind of reminder?

When I wake up, I have to take my medicine immediately and then repeat in 6 hours and then again after 6 hours. Is there an app in which I can click on app button to switch on a reminder series which can give an alarm in 6 hrs and then again in six hours and then auto disable i.e I enable series again next day.

Point is I do not wake up on same time everyday (sometimes differ by many hours) and that makes it's difficult to use normal alarms for me. Medicines must be taken after difference of 6 hours exactly.

Thanks in advance for help.

Sach