Bupivacaine is an amide-type local anesthetic that was prepared by A.F. Ekenstam in 1957 and later FDA-approved in October 1972. It is chemically similar to mepivacaine, with the primary structural difference being a butyl group in place of a methyl group. Bupivacaine is highly potent, exhibiting four times the potency of lidocaine, mepivacaine, and prilocaine, but its toxicity is less than four times that of lidocaine and mepivacaine. Its efficacy and extended duration of action make it a widely used anesthetic in both medical and dental procedures.
The anesthetic is metabolized in the liver by amidases, and around 16% of unchanged bupivacaine is excreted via the kidneys. Bupivacaine has significant vasodilating properties, which are greater than those of lidocaine, prilocaine, and mepivacaine but considerably less than procaine. Its pKa is 8.1, and its pH varies between 4.5 to 6.0 in plain solutions and 3.0 to 4.5 in solutions containing vasoconstrictors.
In clinical use, bupivacaine has a slower onset time compared to other local anesthetics, taking between 6 to 10 minutes to become effective. It is commonly available in a 0.5% solution with 1:200,000 epinephrine, which is particularly useful in lengthy dental procedures that require extended pulpal anesthesia, such as full mouth reconstructions, implant surgeries, or extensive periodontal work. The anesthetic is also beneficial for managing postoperative pain, significantly reducing the need for opioid analgesics when administered for pain control.
The maximum recommended dose of bupivacaine in the United States is 90 mg, although there is no specific dosage guideline based on body weight. In Canada, the dosage is 2.0 mg/kg, with an absolute maximum of 90 mg. Due to its extended duration and delayed onset, bupivacaine is often administered in combination with a faster-acting anesthetic like lidocaine or articaine to provide immediate pain control. For postoperative pain control, it may be administered at the end of a surgical procedure, allowing the patient to leave with adequate pain relief that persists well into the recovery period.
Though bupivacaine is highly effective, it is not recommended for use in children, younger patients, or individuals with a high risk of postoperative soft tissue injury, as its long duration can increase the likelihood of self-inflicted trauma. It is also classified as Pregnancy Category C, indicating that caution is needed when considering its use during pregnancy. The safety of bupivacaine during lactation remains unclear.
