"I'm always scared I will put this on a script. We use lots of keyboard shortcuts for writing labels, and a lot of them are Latin based. What should have been PRN, which stands for pro re nata (when required), lost an N to become PR which stands for rectum," he said.
A Kiwi doctor gave an example of how it should have been written in shorthand, saying: "If I were to rewrite those directions in shorthand they would look like 'inh (inhale) 2 pfs(puffs) po(by mouth) q4h(every 4 hours) prn(if needed)'."
Kiwis have taken to social media to poke fun at the situation, with both pharmacist and patient in the firing line.
"They clearly got confused between asthma and assma," one person wrote.
Another said: "No wonder New Zealand's asthma sufferers have never been cured."
"We've been taking out oral medication wrong this whole time!" one wrote.
According to the New Zealand Asthma Foundation, Ventolin inhalers should be taken orally.
They say that the inhaler should be held upright before being shaken thoroughly.
Breathe out through your mouth and push as much air from your lungs as you can. Put the mouthpiece in your mouth and close your lips around it.
"Push on the top of the canister all the way down while you breath in deeply all the way.
"Take the inhaler out and close your mouth."