If you’re thinking about switching to Part D at all, your number-one priority is to find out what will happen to your medical benefits if you do so.  Most employer or union health insurance combines medical and drug coverage into one package — for you alone, or comprehensively for you, your spouse, and any dependent children — with a single premium. Of course, there are many variations. But whatever kind of deal you have, these are the questions you should get answers to, depending on your circumstances, as soon as possible:

• If I drop just my drug coverage, will I also lose my (and my family’s) medical benefits?
• If I drop my drug coverage, will my spouse (and/or dependent children) lose medical and/or drug benefits if he or she is under age 65?  
• If I drop my drug and/or medical coverage, will I be able to get it back again if I want to return to my present plan?
• If I enroll in a Part D plan because my drug coverage isn’t creditable, will I (and my family) automatically lose my/our medical benefits? 
• If I’m expected to enroll in a specific Part D plan as a condition of continuing to receive drug coverage, will I lose my (and my family’s) medical benefits if I choose to enroll in a different Part D plan? 

These are critical questions. Chances are that your plan’s benefits manager will send you a notice before you turn 65 and each year afterwards informing you of your options for the next year under the plan’s rules. But if you haven’t received such a notice, or remain unsure of the rules, contact the plan immediately to find out where you stand.

If this all sounds too gloomy, let me say that some employer and union plans are more flexible than these questions may suggest. Some do allow enrollees to continue receiving medical benefits even if they drop drug coverage. Some plans will continue benefits for a spouse under age 65 who isn’t eligible for Medicare, even if the enrollee is no longer covered by the plan. And some plans allow enrollees who have dropped out to return at a later date. But, in general, these dispensations are more likely for Medicare-age people who are still working than for retirees.

If you have federal drug coverage under FEHBP, TFC, or the VA, you can choose to have Part D without risking any of your benefits. But be aware that if you’re a retiree with FEHBP or TFC and you cancel it entirely, you can’t get it back.