Concern is mounting over a recently funded antidepressant, with a growing number of patients reporting life-threatening side-effects.
Pharmac's switch to funding Enlafax a year ago saves the drug buying agency $5.4 million a year.
It expected around 1 per cent of the 45,000 patients taking it could experience adverse reactions because of the brand switch. That's about 450 people.
While complaints now stand at over 240 and climbing, support groups say the number of people suffering is far higher.
In a small Bay of Plenty town, one highly experienced GP, Dr Christine Williams, is grappling with the problem.
"I've seen people that had gambling addictions return to gambling and lose their jobs. I've seen marriages break down," Dr Williams told 1 NEWS.
She says this patent behaviour is all linked to the generic antidepressant Enlafax.
"With this particular group of patients I don't have any that are responding to it, not one."
The symptoms of 12 patients are similar to those experienced hundreds of kilometres away by Amy in Marlborough.
"Within two weeks of starting Enlafax I was having nightmares and feeling depressed, thoughts of self harm and suicide," Amy said.
Medsafe is standing by its decision to approve the drug which saw Effexor-XR replaced with the cheaper generic brand Enlafax.
It says the brand switch complies with international best practice and that tests show Enlafax has the same benefits and risks as Effexor-XR.
"They don't switch to a generic without adequate research and investigation," Dr Jan White of the NZMA GP Council said.
Dr White says she has seen no problems from Enlafax at her busy city practice.
But complaints about Enlafax are piling up. The agency monitoring adverse reactions to drugs has now received more than 240 complaints, many identifying side-effects like severe depression and suicidal thoughts.
And a Facebook page set up by patients with adverse reactions claims to have logged 450 negative responses to Enlafax.
They're experiences like those of Amy who says her GP wanted to increase her dose when she became unwell.
The mother of two only learnt about negative side-effects in a 1 NEWS report three weeks ago.
"I'm not sure if I would be here right now if I had waited and stayed on it," Amy said.
Dr Williams said: "I'm sure it's the tip of the iceberg."
And with the prospect of more vulnerable lives unravelling, Dr Williams says it's vital the previous brand Effexor-XR remains available.
Where to get help:
Need to Talk? Free call or text 1737 any time to speak to a trained counsellor, for any reason.
Lifeline: 0800 543 354
Suicide Crisis Helpline: 0508 828 865 / 0508 TAUTOKO (24/7). This is a service for people who may be thinking about suicide, or those who are concerned about family or friends.
Depression Helpline: 0800 111 757 (24/7)
Samaritans: 0800 726 666 (24/7)
Youthline: 0800 376 633 (24/7) or free text 234 (8am-12am), or email firstname.lastname@example.org
What's Up: online chat (7pm-10pm) or 0800 WHATSUP / 0800 9428 787 children's helpline (1pm-10pm weekdays, 3pm-10pm weekends)
Kidsline (ages 5-18): 0800 543 754 (24/7)
Rural Support Trust Helpline: 0800 787 254
Healthline: 0800 611 116
Rainbow Youth: (09) 376 4155
If it is an emergency and you feel like you or someone else is at risk, call 111.