Local Anesthetics and Neuromuscular Blockers

Question 1

Esters VS Amides

Procaine: SHORTEST halflife (1-2mins)

Ropivacaine: LONGEST halflife (4.2hrs)

Answer 1

Esters: have only 1 i in their names
Tetracaine, Procaine, Benzocaine

Amides: have 2 i’s in their names
Bupivacaine, Ropivacaine, Lidocaine

Question 2

Why should you NOT inject local anesthetics into an abscess during incision and drainage?

Answer 2

Weak bases in charged/ionized form predominates (below pKa) which will not be able to cross nonpolar membranes.

Question 3

Relationship of LA with electrolytes

Answer 3

Hyperkalemia enhances LA activity

Hypercalcemia antagonizes LA activity

Question 4

Effect of LA toxicity to CVS

Answer 4

May cause heart block and arrhythmias

Question 5

ALL Local anesthetics are VASODILATORS EXCEPT

Answer 5

Cocaine: sympathomimmetic, blocks catecholamine receptors

Question 6

Local anesthetic (Ester) used in EXTRAVASATION COMPLICATIONS from VENIPUNCTURE, inadvertent intraarterial injections
KNOWN to have SHORTEST HALF-LIFE among LAs

AE: Light headedness, sedation, ANTIBODY FORMATION/ALLERGONIC, cvs and pulmo depression

Answer 6

Procaine

SimD: Novocaine

Question 7

Local anesthetic (Ester) used as TOPICAL ANESTHESIA

AE: Light headedness, sedation, ANTIBODY FORMATION/ALLERGONIC, SKIN IRRIATION, cvs and pulmo depression

Answer 7

Benzocaine

SimD: Butamben

Use CAUTIOUSLY when treating BURNS or large areas of skin

Question 8

Local anesthetic (Ester)/ DRUG OF ABUSE used as TOPICAL ANESTHESIA

AE: Light headedness, sedation, ANTIBODY FORMATION/ALLERGONIC, cvs and pulmo depression, ABUSE LIABILITY, SEVERE HPN, CEREBRAL HMG, ARRHYTHMIAS, MI

Answer 8

Cocaine

Question 9

Local anesthetic (Ester) used in SPINAL ANESTHESIA, EPIDURAL ANESTHESIA and TOPICAL OPHTHALMIC ANESTHESIA

AE: Light headedness, sedation, ANTIBODY FORMATION/ALLERGONIC, cvs and pulmo depression

Answer 9

Tetracaine

Question 10

Local anesthetic (Amide) used as LA and ANTIARRHYTHMIC (Group 1B, used for POST-MI and for digitalis toxicity)

Answer 10

Lidocaine

Toxic dose: 5mg/kg
for any drug solution, 1% = 10mg/mL

Question 11

Local anesthetic (Amide) used as DENTAL ANESTHESIA which may cause METHEMOGLOBINEMIA

Answer 11

Prilocaine

Prilocaine sound like PiRanha = NGIPIN -> Dental anesthesia
Methylene blue given if methemoglobinemia develops

Question 12

Local anesthetic (Amide) used in EPIDURAL ANESTHESIA and INTRATHECAL ANESTHESIA

Answer 12

Bupivacaine

BuPI pang ePIdural

Use in CAUTION for PREGNANT WOMEN
Treat cardiotoxicity with INTRALIPID (fat emulsion in TPN)

Question 13

Local anesthetic (Amide) used in EPIDURAL ANESTHESIA

AE: cardiotoxicity

Answer 13

Ropivacaine

Half-life as LONG as a ROPe

Longest half-life among LA
CI in IV regional anesthesia
Treat cardiotoxicity with INTRALIPID (fat emulsion in TPN)

Question 14

Neuromuscular paralysis that results from persistent depolarization of the end plate

Answer 14

Depolarizing blockade

Ex. Succinylcholine

Question 15

Neuromuscular paralysis that results from pharmacologic antagonism at the acetylcholine receptor of the end plate

Answer 15

Non-depolarizing blockade

Ex. Tubocurarine

Question 16

Nondepolarizing neuromuscular blocker which has the most rapid onset time

Answer 16

Rocuronium (60-120s)

Question 17

LONG-ACTING nondepolarizing neuromuscular blocker used in intubation and general anesthesia which is relatively CONTRAINDICATED in Myocardial Ischemia

AE: GANGLION BLOCK (Hypertension), RECURARIZATION, respi paralysis, histamine release

Answer 17

Tubocurarine

Reverse effects with NEOSTIGMINE

Tubocurarine: Ang TUBO ay mahaba. (long-acting)

Question 18

SHORT-ACTING nondepolarizing neuromuscular blocker used in intubation and general anesthesia

Answer 18

Mivacurium

Reverse effects with NEOSTIGMINE
Metabolized by pseudocholinesterase

Question 19

INTERMEDIATE-ACTING nondepolarizing neuromuscular blocker used in intubation and general anesthesia which may cause BRONCHOSPASM and undergoes HOFFMAN elimination (rapid spontaneous breakdown

Answer 19

Atracurium

SimD: Cistracurium

Ang aso ni Remi na si pATRAsh ay walang ginawa kundi magHOFF! HOFF! HOFF! (tumahol)

Reverse effects with NEOSTIGMINE

Question 20

INTERMEDIATE-ACTING nondepolarizing neuromuscular blocker used in intubation and general anesthesia which undergoes BILE ELIMINATION

Answer 20

Vecuronium

Potentiated by inhaled anesthetics, aminoglycosides and quinidine

Reverse effects with NEOSTIGMINE

Question 21

INTERMEDIATE-ACTING nondepolarizing neuromuscular blocker used in intubation and general anesthesia which may cause HYPERSENSITIVITY

Answer 21

Rocuronium
MOST RAPID time of onset (60-120s)

Reverse effects with NEOSTIGMINE
SUGAMMADEX: novel reversal agent for rocuronium

Question 22

LONG-ACTING nondepolarizing neuromuscular blocker used in intubation, GA, EUTHANASIA, LETHAL INJECTION, STYCHNINE POISONING

AE: respi paralysis, apnea, tachycardia, HPN, RECURARIZATION

Answer 22

Pancuronium

PANcuronium: PANmatagalan (long-acting)

Reverse effects with NEOSTIGMINE

Question 23

Drugs used in Lethal Injection

Answer 23

Thiopental (5g)
Pancuronium (100mg)
Potassium chloride (100mEq)

Question 24

Phases of Depolarizing blockade

Answer 24

Phase I DEPOLARIZATION - transient fasciculation followed by paralysis

Phase II DESENSITIZATION - membrane repolarizes but desensitized to Ach

Question 25

Depolarizing neuromuscular blocker used in intubation and general anesthesia which may cause MUSCLE PAIN, hyperkalemia, increased IOP and intragastric pressure (aspiration) and MALIGNANT HYPERTHERMIA

Answer 25

Succinylcholine

Metabolized by pseudocholinesterase

Question 26

Potentially life-threatening condition caused by succinylcholine (and tubocurarine) with inhaled anesthetics (halothane)

Answer 26

Malignant hyperthermia

due to massive Calcium release from sarcoplasmic reticulum of skeletal muscles

Question 27

Early sign of malignant hypertherma and its treatment

Answer 27

Contraction of jaw muscles or Trismus

Treated by rapidly cooling patient and by administration of DANTROLENE