Carrots and sticks

A young man presents to casualties with asthma that seems reasonably severe, with poor oxygenation despite 15mg of nebulised albuterol. He is still tight and has fairly horrible PFTs (FEV1/FVC of 44% post-albuterol) so I commence him on an albuterol infusion.

Several hours later when I discuss the need for admission, he declines and I convince him to at least allow us to wean the infusion before he walks out. He signs out AMA eventually after the infusion is weaned. He then comes to me and requests an albuterol puffer.

I mention that it is available OTC; he states that he cannot afford it. I offer to write a prescription (which reduces the cost from $11 to $5). He states that he still cannot afford it. I decline to provide him with hospital-stock albuterol. He threatens to make a complaint.

I am of the opinion that at the point at which he signs out AMA, he is no longer my patient and my duty of care is discharged. I have told him why I think he needs to remain in hospital and he accepts the risks of leaving. He makes his choices and he lives with them.

Should I have given in? or is this acceptable use of a carrot?