No, the drug plans select which drugs they want to cover and decide what tier (i.e., how the plan has ranked the drug on its formulary) the drug will be on which will then define what the pricing will be for that drug.
If you drug is not covered by the Part D plan you are on, ask your doctor for the name(s) of similar drugs to see if those drugs are covered by your current plan.
And yes, drug plans can have restrictions:
* drug requires prior authorization before dispensing the drug.
* there are quantity limits for certain prescription drugs.
* some plans require step therapy (verification that you have used less expensive drugs for your condition) before potentially allowing coverage.
If you receive a written denial of coverage of a drug from your drug plan, you can pursue the plan’s appeal process for an exception.