The backs of her legs were covered in bruises and she was admitted to hospital.
Two weeks later, the pharmacy manager did a stock take and discovered the pharmacist's error.
The pharmacist, who also has name suppression, had mistakenly dispensed epoetin alfa injections (for the treatment of severe anaemia of renal [kidney] origin) in place of the prescribed medication.
The pharmacy manager contacted the woman, who was still overseas, and informed her of the error.
According to the drug's website, serous side effects may include blood clots.
Health and Disability Commissioner, Anthony Hill, released a report finding the pharmacist in breach of the Code of Health and Disability Services Consumers' Rights for dispensing the wrong medication.
Hill considered that it was clear from the dosage prescribed to the woman that she was a high-risk patient.
He was critical of the pharmacist for failing to ensure that the correct medication was dispensed in accordance with the professional standards set by the Pharmacy Council of New Zealand.
The pharmacist also did not check the label against the prescription adequately.
In Hill's opinion, the error was the pharmacist's alone, as the pharmacy had appropriate standard operating procedures in place and the pharmacist was aware of the dispensing requirements.
Hill recommended that the pharmacist arrange for an assessment through the New Zealand College of Pharmacists regarding the processing of prescriptions and processes for dispensing and checking medications.
He also recommended that the New Zealand Pharmacy Council consider whether a review of the pharmacist's competence is warranted, and report back to HDC on the outcome of that review.