My father has PMR and I have a different inflammatory arthritis along with other chronic pain conditions. He gets debilitating fatigue from PMR flares. We've both been taking low dose naltrexone (LDN) for fatigue.

It's a little off the beaten track and harder to obtain, but I thought I'd mention it. It's by prescription from a compounding pharmacy because it's a fraction of the regular doses of naltrexone. By micro-dosing it, research has found that it seems to increase the amount of endorphins and regulate glial cells (which when overactive contribute to chronic pain).

It's been used for years off-label for chronic pain and fatigue, fibromyalgia, as well as some autoimmune conditions. But it seems to me it's gaining more traction because people are looking at it for use in long COVID.

It can be difficult to get an RX for it because many providers aren't aware of it unless they're working a lot with chronic pain patients (in my experience), but it was worth it. I can't vouch for if it's improved my chronic pain, but I know it's helped my fatigue. It helps my dad as well; or at least he thinks it does.

Oh, another huge plus: Very low risk of side effects.