Bupivacaine is about 95% bound to plasma proteins. Reported half-lives are from 1.5 to 5.5 hours in adults and about 8 hours in neonates. It is metabolised in the liver and is excreted in the urine principally as metabolites with only 5 to 6% as unchanged drug.
Bupivacaine is distributed into breast milk in small quantities. It crosses the placenta but the ratio of fetal concentrations to maternal concentrations is relatively low. Bupivacaine also diffuses into the cerebrospinal fluid.
Indication & Dosage
Infiltration anaesthesia, epidural and spinal aesthesia, nerver block.
Dosage: Max. dose is 150mg a 4-hour period.
Blocks the generation and conduction of nerve impulses. Order of loss of function is as follows: Pain, temperature, touch, proprioception, and skeletal muscle tone. Toxic levels may depress cardiac conduction, excitability, and cardiac arrest.
Local infiltration :
Caudal, Epidural, Peripheral
nerve block when muscular relaxation is not important : 0.25% solution.
where some muscular relaxation is needed : 0.5% solution
Either strength can be gicen for local infiltration for painful musculoskeletal disorders, incisional, infiltration for postoperative pain relief etc : Dosage varies with individual patients, vascularity of the region and rat of absorption. Doses upto 225mg of bupivacaine with adrenaline or 175mg without adrenaline may be used. For epidural block 5% solution can be accidental intra-vascular or intrathecal injection
Spinal Anaesthesia: Bupivacaine 5%+dextrose 80mg/m 7.5-12mg of bupivacaine can be used for spinal anaesthesia for lower extremities and perineal procedures and vaginal hysterectomy.
Effect & Precaution
Cardiac arrest, cardiac arrhythmias, respitatory failure.
Precaution: Heart block, hepatic dysfunction, shock, heart disease, debililated patients
Pregnancy: Caution, use only when clearly indicated.
Breast Feeding: Use with caution.
Man: Use with caution.