It's a capsule filled with pure naltrexone powder and a fast release filler. It must be compounded (Skips Pharmacy does it for me)

The Chemo med you're thinking of is Navatrone and it is a chemo drug. LDNaltrexone is not a chemo drug. There are no lasting or detrimental side effects to LDN...unless you are allergic, which is always a possibility.

My 4.5mg capsules cost me about 15.00 per month. Not all insurance will cover it, since it's used off label for MS, but some do. The cost is low though so it's pretty affordable.