A man who allegedly took a drug believed to be behind a series of violent and gruesome incidents around the world had to be given a high dose of sedative to restrain him after he continued "thrashing about" despite being tasered twice by police.
Police were called to a street in Greenhithe, Auckland, at 4am on Sunday because a 27-year-old man was "running amok".
He is understood to have taken an illegal synthetic drug derived from mephedrone or MDPV and known as "bath salts".
The drug came to worldwide attention last month after several violent incidents overseas. Two Toronto police officers were taken to hospital with broken bones in their faces, hands and wrists after they were set upon by a "raging" man. It is believed that he had also taken bath salts.
There have also been reports in the US of people mutilating themselves after taking bath salts. One man skinned himself alive while on the drug and another stabbed himself multiple times and threw his own intestines at police.
A source said the Greenhithe man was "very agitated" towards the officers when they arrived at the scene.
"A physical arrest proved too troublesome and risky - someone would have been injured," he said.
"OC [pepper] spray was used but had no effect and eventually police had to use a Taser.
"The two officers were aware of the drug the man had taken and knew from overseas case reports it was a stimulant that could cause extreme violence including severe bite wounds.
"The man's momentum at the time was of such magnitude that the Taser prongs detached from his body. He immediately recovered and police had to use the Taser a second time - with much more success."
However, being tasered twice did not stop the man completely, and he was taken into custody using "special safety restraint equipment".
"Ambulance officers tried to sedate him from thrashing about for fear he would injure a tendon or a joint, but had to get permission to exceed normal dosage as the medication was having no effect."
The man will appear in the North Shore District Court on Friday charged with wilful damage, resisting arrest and assaulting two police officers.
The source said it was rare for a Taser barb to become detached.
"But the man's forceful momentum kept him moving after he fell to the ground until one of the prongs came free."
He said people severely affected by drugs were less likely to be incapacitated by pepper spray and police had training to deal with that situation.
"The drug bath salts is so called because it's a fine white crystal, not dissimilar in appearance to the sort of thing granny used in her bathwater. "The effects can differ from person to person, and long-term effects are unknown. It's not very common, but recently supplies have made their way here. Police warn anyone crazy enough to try this stuff that there are extreme risks."
The penalty for possession is three months in prison or a $500 fine.
"While that might seem very modest, the courts are more interested in getting users into professional assistance programmes."