Variable dosing syringe

A plunger rod assembly for a syringe comprising:

• a main body;
• a plunger rod at least partially received in the main body and comprising a set of one or more protrusions;
• and
• a dosage setter operatively coupled to the plunger rod and comprising a rotatable body that comprises a set of one or more stops for engaging the set of one or more protrusions of the plunger rod depending on at least a rotational position of the set of one or more stops relative to the set of one or more protrusions, wherein a first rotational adjustment associated with the dosage setter is configured to set a first dosage increment by adjusting a relative axial position between the rotatable body and the plunger rod, and a second rotational adjustment associated with the dosage setting assembly is configured to set a second dosage increment that is larger than the first dosage increment by adjusting a relative rotational alignment between the set of one or more stops and the set of one or more protrusions.