What it means
Plans use quantity limits for safety and cost reasons. Medicare.gov gives the example of a plan covering only 30 tablets of a drug per month. For weekly injectable GLP-1 medicines, a plan might cover one carton of pens per 28 days.
Formularies often mark these drugs with "QL." A quantity limit can also affect dose changes. Some plans cover only one strength at a time, or require a new prior authorization when the dose goes up.
If your prescriber believes the limit is not medically appropriate for you, they can request an exception. The plan may ask for a statement explaining why.
Quantity limits can also make travel tricky. If you need an early refill before a long trip, ask your pharmacy and plan well ahead of time, since a vacation override is not always available.
Why it matters
Quantity limits can block a dose increase or early refill until the right paperwork is filed.