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