184 / 795
3. 
3.1.3.10.3. Table - Local anaesthetics Local anaesthetics
| Potency | pK |
Nonionised fraction at pH 7.4 |
Lipid solubility | Relative lipid solubility | Protein-binding | Vd (L/kg) | Toxic dose | Onset | Duration | Elimination T1/2 | Clearance | |
| Ester LA | ||||||||||||
| Procaine | 1 | 8.9 |
3% |
0.6 | 6% | 1 L/kg | Slow | 45 - 60 min | 9 min | |||
| Chloroprocaine | 4 | 8.7 | 5% | 0.5 L/kg | Rapid | 30 - 35 min | 7 min | |||||
|
Amethocaine |
16 | 8.5 | 7% | 80 | 76% | Slow | 1 - 3 hrs | |||||
| Benzocaine | 3.5 | |||||||||||
| Cocaine | ?8.5 | |||||||||||
| Amide LA | ||||||||||||
| Lignocaine | 1 | 7.9 | 25% | 2.9 | 1 | 70% | 1.3 L/kg | 4mg/kg OR 7mg/kg with adrenaline | Rapid | 1 - 2 hrs | 1.6 hours | 13.6 mL/kg/min |
| Etidocaine | 4 | 7.7 | 33% | 141 | 39 | 94% | 1.9 L/kg | Slow | 4 - 8 hrs | 2.6 hours | 17.4 mL/kg/min | |
|
Prilocaine |
1 | 7.9 | 24% | 0.9 | 55% | 2.7 L/kg | 6mg/kg | Slow | 1 - 2 hrs | 1.6 hours | ||
| Pipecoloxylidide | ||||||||||||
| Mepivacaine | 1 | 7.6 | 39% | 0.8 | 77% | 1.2 L/kg | Slow | 1.5 - 3 hr | 1.9 hours | 139.7 mL/kg/min | ||
| Bupivacaine | 4 | 8.1 | 17% | 27.5 | 10 | 95% | 10.4 L/kg | 2mg/kg | Slow | 4 - 8 hrs | 3.5 hours | 6.7 mL/kg/min |
| Levobupivacaine | 4 | 8.1 | 17% | >97% | 0.79 L/kg | Slow | 4 - 8 hrs | 2.6 hours | ||||
| Ropivacaine | 4 | 8.1 | 17% | 2.9 | 94% | 0.84 L/kg | 3mg/kg | Slow | 4 - 8 hrs | 1.8 hours | 6.3 mL/kg/min |
NB:
- Relative lipid solubility is based on relative heptane:buffer partition coefficient
- Vd and clearance is a rough estimation, calculated using figures in Stoelting, assuming 70kg body weight
- Chloroprocaine
* Rapid onset despite high pK, due to the high concentration used (3%) - Amethocaine
* High potency
* Slow metabolism
* Used topically on eyes - Benzocaine
* Very low pK
* Almost entirely non-ionised at physiological pH - Despite ropivacaine has a lower clearance than bupivacaine in the table [SH4:p181], text in [SH4:p186] says it has higher clearance