Australian healthcare regulators issued renewed warnings to patients using Medtronic’s (NYSE:MDT) Paradigm insulin pumps, cautioning that an accidental button-press may result in a potentially dangerous overdose.

The Paradigm pumps, which deliver both continuous and bolus-based doses of insulin, can switch from a zero bolus setting to a maximum dose with a single click when in certain modes. An accidental press of the button may result in a patient mistakenly dispensing the maximum dose of insulin.

A small number of overdoses have already been reported, with one patient hospitalized for severe hypoglycemia, according to the warning. Medtronic has taken steps to warn patients and healthcare providers, a move that Australian regulators sought to reinforce with new warnings.

The Paradigm pumps have been the subject of warnings in the past. In July 2013 the FDA put its highest-risk Class I label on a recall of Paradigm and Polyfin insulin pumps, issued over concerns that the devices may over- or under-deliver insulin if certain components are contaminated with insulin or other fluids. One month earlier Medtronic’s Canada division announced that it received 2 reports associating its Paradigm and Polyfin infusion pumps with instances of under- or over-delivery of insulin.

Just over a year ago Australian regulators warned of 3 potential safety issues associated with the Paradigm pumps, adding that "these issues are rare and it is unlikely that you will need to replace your Medtronic Paradigm Insulin Pump."

Issues included loose support caps, a sensor graph timeout and the dangers of exposure to water damage.

Medtronic’s stock lost few points on Wall Street today after the medtech titan was hit with a major loss against arch-rival Edwards Lifesciences (NYSE:EW). MDT shares were down 2% to $57.98 as of about 2 p.m. EST.