What does SL mean on a prescription?
SL means sublingual, that is, under the tongue.
What it stands for
SL comes from the Latin sub lingua, meaning under the tongue. It tells you the route: the medication dissolves in place rather than being swallowed.
How it looks on a real label
| Sig code | Label directions |
|---|---|
1 tab sl prn chest pain | Take 1 tablet under the tongue as needed for chest pain |
The point of the sublingual route is speed. The tissue under the tongue absorbs directly into the bloodstream, so the medication skips the stomach and the first pass through the liver that would otherwise break much of it down.
That is why it is used where minutes matter. Swallowing an SL tablet does not just slow it down, it can waste the dose entirely.
A patient counselled on an SL medication should be told not to eat, drink or swallow while it dissolves, which is the part most often missed.
Related codes
| Code | Meaning |
|---|---|
PO | by mouth |
PRN | as needed |
STAT | immediately |
TOP | topically |
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This page is educational and is not medical advice. Always follow the directions on your own prescription and ask your pharmacist if anything is unclear.