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INTRODUCTIONOF TWO NEW ANESTHETIC
AGENTS
Dr.G.k.kumar
Ropivacaine
Dexmeditomedine
Ropivacaine
Ropivacaine
• New local anesthetic agent
• Introduced in 1996.
• In India 2009.
Ropivacaine
• Lower systemic toxicity
• Safest long acting local anesthetic agent.
* Groban et al. Anesth Analg, 2001. Ohmura et al. Anesth Analg, 2001. Santos et al. Anesthesiology, 2001.
Ropivacaine -Pharmacology
Ropivacaine-Pharmacology
• Long acting LA agent.• Aminio amide.• Pure enantiomer -S isomer.
Ropivacaine-Pharmacology
• Greater selectivity for sensory blockade
-binds selectively to Na⁺channels 1.7• Shorter motor block
*Liu BG et al, AnesAnalg.2000May. Simpsons D et al,2005
Ropivacaine-Pharmacology
•Ropivacaine is less lipid soluble.•A smaller volume of distribution.•Greater clearance. •Shorter elimination half-life than bupivacaine.
-Shorter duration of action esp motor blockade – early recovery.
Ropivacaine-Pharmacology
•Ropivacaine undergoes hepatic biotransformation and renal excretion•Excreted 86% as metobolites
•Safe in CESLD & CESRD
*Jokinen MJ et al, Anesthesiology,2007Jan. Jokinen MJ et al,Clinical Anesthesiology,2005
Ropivacaine-Pharmacology • The specific gravity of
Ropivacaine Injection -from 1.002 to 1.005 at
25°C. -Isobaric
Ropivacine-Safe Dose
• 3-5mg /kg.• Pediatric-1-2mg/kg
Ropivacaine-Epidural dose
Drug Conc% Volume Dose mg Onset Duration
BUPI 0.25-0.5 15-30 40-225 15-20 180-350
LEVO 0.25-0.75 15-30 40-250 15-20 180-350
ROPI 0.25-0.75 15-30 40-250 15-20 180-350
*Miller’s anesthesia,7th edition
Ropivacaine-Spinal dose
Drug (%) Volume (mL)
Total Dose (mg)
Baricity Duration (min)
Bupi 0.5 3-4 15-20 Iso 90-2000.75 2-3 15-20 Hyper 90-200
Levo0.5 3-4 15-20 Iso 90-2000.75 2-3 15-20 Hyper 90-200
Ropi 0.5 3-4 15-20 Iso 90-2000.75 2-3 15-20 Hyper 90-200
*Miller’s anesthesia,7th edition
Ropivacaine – clinical efficacy
• When used for spinal anesthesia, 0.75% ropivacaine produces less intense sensory and motor block than 0.5% bupivacaine.
• Equipotent to bupivacaine when used for lumbar epidural labor analgesia and C-section.
Ropivacaine – clinical efficacy
• In epidural and other blocks bupivacaine and ropivacaine demonstrate similar intensity of sensory anesthesia.
Ropivacaine – clinical efficacy
• Ropivacaine motor block -delayed in onset. -less intense. -shorter in duration.
Toxicity
• Ropivacaine < Levobupivacaine < Bupivacaine
• Even at 50% higher dosage!!!
*Dony et al. Anesth Analg, 2000
Toxicity• Tolerated blood conc. level [ROP] >> [BUP] = [LBUP]• Mortality: BUP (50%) > LBUP (30%) > ROP (10%)
• * Groban et al. Anesth Analg, 2001.• Ohmura et al. Anesth Analg, 2001.• Santos et al. Anesthesiology, 2001.
Ropivacine-Why Safer Than Bupivacaine?• Bupivacaine is a 50:50 racemic
mixture of the S- and R-enantiomers.
• The R isomer has greater affinity and binding time for voltage-gated sodium channels, and so cardiotoxicity.
Ropivacine-Why Safer Than Bupivacaine?
• R-bupivacaine is also more arrhythmogenic.
• Slows ventricular conduction 4.6 times as much as S-bupivacaine.
Ropivacine-Why Safer Than Bupivacaine?
• The Ropivacaine is the pure S-enantiomer so decreased cardiotoxicity .
Ropivacine-Why Safer Than Bupivacaine?
• Cumulative doses up to 770 mg over 24 hours (intraoperative block plus postoperative infusion)
• Continuous epidural infusion at rates up to 28 mg per hour for 72 hours have been well tolerated in adults, ie, 2016 mg plus surgical dose of approximately 100-150 mg as top-up.
*www.fda druginformation.com
Ropivacine-Why Safer Than Bupivacaine?
• Ropivacaine has a larger therapeutic index
• 70% less likely to cause severe cardiac dysarrhythmias
• Greater CNS tolerance• The improved safety profile is
due to a lower lipid solubility
Ropivacaine
HYPE?
HOPE?
LA toxicity more in
• Heart block, HT, structural heart disease.
• >65yr,<12yr.• Pregnancy.• Acidosis.• Liver dysfunction.• Acutely ill and debilitated.
Role of Ropivacaine
• SAFE PRACTICE• Pediatric patients.• Geriatric patients.• Continuous infusions.• For labour analgesia.• Rescue spinal anesthesia.
Ropivacaine
LA toxicity treatment
• Supportive care: intubation, vasopressors, appropriate defibrillation, fluids, stop injection of LA.
• Intralipid…Bolus 1cc/kg of 20% intralipid, 0.25cc/kg/min of 20% intralipid for 10 minutes
• Bolus can be repeated every 5 minutes up to a maximum of 8cc/kg of 20% intralipid
LA toxicity treatment
• Cardiac support should be continued as ACLS dictates
• Adrenaline and vasopressin are usefull.
Ropivacaine