The present invention relates to a reservoir unit (40, 140, 240) for a drug delivery arrangement (1, 100, 200), the reservoir unit (40, 140, 240) comprising: a housing (41, 141, 241) adapted to accommodate a fluid substance and comprising a displaceable wall (43, 143, 243), a fluid transport member (50, 150, 250) comprising a fluid outlet (52, 152, 252), first fluid communication means (53, 153, 253) for providing fluid communication with an interior of another reservoir, and second fluid communication means (54, 154, 254) for providing fluid communication with an interior (44, 144, 244) of the housing (41, 141, 241), and coupling means (45, 145, 245) adapted for connection with mating coupling means associated with the other reservoir. The invention further relates to a drug delivery arrangement (1, 100, 200) employing the reservoir unit (40, 140, 240). The fluid transport member being a needle (50) fixedly retained by the outlet portion (42) and having a side hole (54) in the needle body (51) just proximally of the outlet portion (42).
