Marcaine
Meaning of Marcaine: Long duration is the whole point of this anesthetic, and the same property explains why it is handled with more caution than its relatives.
Definition of Marcaine
Marcaine is a brand name for bupivacaine, a long-acting local anesthetic injected to numb part of the body. It blocks the sodium channels that nerve fibers use to carry electrical signals, so messages about pain never reach the brain. It is a mainstay of epidurals, spinal anesthesia and nerve blocks, and its effect lasts several hours.
How does it stop pain?
A nerve carries a signal as a wave of electrical change, and that wave depends on sodium rushing in through gates in the nerve membrane. Bupivacaine slips into those gates and holds them shut. No wave forms, so nothing travels along the fiber. Thin fibers carrying pain and temperature are blocked before the thick fibers carrying touch and movement, which is why an area can feel numb to a pinprick while still moving. The block is local and temporary, unlike a general anesthetic, which acts on the brain and removes consciousness.
How does it compare with other local anesthetics?
| Drug | Onset | Duration |
|---|---|---|
| Lidocaine | Fast | Short, an hour or two |
| Bupivacaine | Slower | Long, several hours |
| Ropivacaine | Slower | Long, with less effect on the heart |
The long duration is what suits it to surgery and to labor, where a block has to outlast the procedure that prompted it. The trade-off is that the same property makes an accidental injection into a blood vessel more serious, since the drug lingers there too.
Why is it handled carefully?
Local anesthetics cause trouble mainly when they leave the place they were put. If bupivacaine reaches the bloodstream in quantity it disturbs the electrical system of the heart, and it does so more readily than shorter-acting alternatives, which is why total dose is capped and injections are made with checks that the needle is not sitting in a vessel. Describing it as a drug under study for pain after cancer surgery understates a medicine in routine use for decades. Sensorcaine is another brand of the same molecule.
Also known as
Used in a sentence
Marcaine was infiltrated around the wound before closure.
Good to know
Bupivacaine is a long-established local anesthetic rather than an investigational one, and its effect on the heart if it enters the circulation is the reason total dose is limited.