Yes - it's good to be cautious.

I probably should have emphasized the *tablets* part,
and also said that the capsules *do* contain lactose.

It's important to read up on any medication. Visit the
drug manufacturer's web site or ask your pharmacist for
the prescribing information about a medication, or have
your doctor look in the PDR (Physician's Desk Reference)
to check the inactive ingredients. You can also read the
PDR at most public libraries, in the reference section.

Once you've found a medication that is lactose-free,
have your doctor write for that medication only, with NO
SUBSTITUTIONS indicated on the prescription. Otherwise,
you take your chances. Depending on your coverage, this
may cost you more.

It also helps to periodically re-check the inactive
ingredients, especially if the pills look different or
if symptoms arise.