Lisinopril seems to put a heavy detoxification load on the immune system. As a result, the body seems to use up zinc and selenium (and other things, of course, like vit-c, vit-e) at a high rate.
When the body runs out of zinc or selenium, additional problems happen. The immune system is not able to keep up with the detoxification needs, and I think this is a major factor with the cough.
In addition, other systems besides the immune system are also negatively effected when these nutrients run low. For example, selenium, is very important for joint health, and, it is also key in thyroid function (both at the receptor site as well is in the thyroid itself), among other things.
The combination of direct lung damage related to the cough, plus the lowered thyroid function from lack of selenium seem to me to be the major causes of the breathlessness or shortness of breath problems that I've had so much of.
Another problem is that taking selenium supplementation, even when deficient in selenium, further depresses the thyroid. So, I have found a number of things that help me counteract that, in order that I can take the necessary amount of supplemental selenium to feed my immune system. These other things are calcium, boron, iodine, tyrosine, zinc, magnesium. Also, I take the extra selenium only at night, when extra thyroid depression is more tolerable.
Also, for really damaged lungs, as mine were, I found that cysteine, msm, and horsetail (for silicia) also helpful.
And to help with the stomach problems that lisinopril caused me, I found glutamine helpful.
My problems persisted for a long time (2+ years) after quitting lisinopril, however, each time I discovered one of these helpful nutrients, my recovery took a leap forward. I'm pretty sure that if I'd known right away about the zinc & selenium, in particular, I'd have been able to get back on my feet in several months instead.