The current techniques provide a system for monitoring a physiological parameter of a patient using microneedles that are coupled to an optical system, allowing spectroscopic measurements to be made immediately below the outer layer of the epidermis. In embodiments of the present invention, the results of the spectroscopic measurements are used to control the administration of a drug through an intravenous tube. In other embodiments, the microneedles may be coated with a drug for administration to the patient. In other embodiments, the microneedles may be mounted in a probe, wherein an actuator is used to move the needles into contact with the skin, and a drug delivery system is used to infuse the drug into the patient. A method for making needles is also provided.