PAIN DRUGS HANDBOOK TABLE
OF CONTENTS
About the
Author
About
the Handbook
Acknowledgments
Forward
to 2rd Edition
Forward
to 1st Edition
DRUGS (Alphabetical Order)
TOPICAL AGENTS
Amitriptyline
Baclofen
Clonidine
Cyclobenzaprine
2-deoxy-d-glucose
Dexamethasone
Dextromethorphan
Diclofenac
Doxepin
DMSO
Gabapentin
Ketamine
Ketoprofen
NEUROLYTIC AGENT
Phenol
APPENDICES
Appendix 1: World Health Organization
Three-step Ladder
Appendix 2: Drug Tables
Appendix 3: Infusion Tables
Appendix 4: Relative Potencies of
Opioids Effects
Appendix 5: Relative Potencies of Steroids
Appendix 6: Intravenous PCA
Standard Orders
Appendix 7: Patient Controlled Analgesia Flow Sheet
Appendix 8: Relative Potencies of Opioids
Appendix 9: Epidural Analgesia Monitoring Orders
Appendix 10: Pain Rating Scales
Appendix 11: Multiplication Factors for Converting the
Daily Dose of a Prior Opioid to the Daily Dose of Oxycontin
Appendix 12: CPR Algorithms
Appendix 13: Pediatric CPR Algorithms
Appendix 14: Trade Name Table
BIBLIOGRAPHY
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Sota
Omoigui's
Pain Drug Handbook
2nd Edition:
Tetracaine
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SECTION
ONE:
Class,
Uses, Dosing,
Elimination
SECTION TWO:
Preparation, Pharmacology, Pharmacokinetics
SECTION THREE:
Interactions, Toxicity
Guidelines/Precautions
Principal Adverse Reactions
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Class
(LOCAL ANESTHETIC)
Uses
regional and topical anesthesia
Dosing
Spinal: bolus/infusion 5-20 mg [Children 0.4 mg/kg with a minimum of 1 mg.] (1% solution). Dilute dose with equal volume of supplied Dextrose solution (hyperbaric) or Cerebrospinal fluid (isobaric) or Sterile water (hypobaric).
Brachial Plexus Block: Combine 0.5-1 mg/kg tetracaine with 30-50 mls (0.5- 0.75 mls/kg) of bupivacaine (0.25-0.375%) or lidocaine (1%) or mepivacaine (1%).
Topical (Spray): Apply 2% solution for 1 second (never more than 2 seconds). Average expulsion rate of residue from spray is 200 mg per second.
Max. Safe Dose: 1-1.5 mg/kg (without epinephrine)
2.5 mg/kg (with epinephrine)
Solutions containing preservatives should not be used for spinal block. Except where contraindicated, vasoconstrictor drugs may be added to increase effect and prolong local or regional anesthesia For dosage/route guidelines, see Epinephrine, Dosing . Do not use vasoconstrictor drugs for IV Regional Anesthesia or Local Anesthesia of end organs (digits, penis, ears).
Elimination
plasma cholinesterase
Preparation
Tetracaine HCL (Pontocaine)
Injection: 1% with 10% dextrose, 0.2% in 6% dextrose, 0.3% in 6% dextrose.
Powder for reconstitution: 20 mg
Tetracaine HCL and Benzocaine and Butyl Aminobenzoate (Cetacaine Topical)
Topical Solution: Tetracaine 2%, Benzocaine 14% and Butyl Aminobenzoate 2%
Pharmacology
This ester of para-amino benzoic acid is a potent long acting local anesthetic. Tetracaine stabilizes the neuronal membrane and prevents initiation and transmission of nerve impulses. It has a prolonged duration of action compared with procaine and chloroprocaine secondary to a much slower rate of hydrolysis by plasma cholinesterase. The duration of action may be further prolonged by the addition of vasoconstrictor drugs to delay systemic absorption. High plasma levels may produce seizures and cardiovascular collapse secondary to a decrease in peripheral vascular resistance and direct myocardial depression.
Pharmacokinetics
ONSET OF ACTION: topical: < 30 seconds infiltration: 15 mins spinal: <10 mins.
PEAK EFFECT: Infiltration/ spinal: 15 mins-1 hour
DURATION OF ACTION: infiltration: 2-3 hrs spinal: 1.25-3.0 hrs.
Interactions
prolongs the effect of succinylcholine; metabolite (PABA) inhibits the action of sulfonamides and aminosalicylic acid; toxicity enhanced by cimetidine, anticholinesterases (which inhibit degradation); benzodiazepines, barbiturates and volatile anesthetics increase seizure threshold; duration of regional anesthesia prolonged by vasoconstrictor agents e.g. epinephrine and alpha 2 agonists e.g. clonidine; alkalinization increases rate of onset and potency of local or regional anesthesia.
Toxicity
Toxic range:
Serum levels > 8 mcg/ml
Manifestations:
Hypotension
Confusion
Slurred speech
Perioral numbness
Tinnitus
Seizures
Arrhythmias
Circulatory Collapse
Respiratory depression
Cardiac Arrest
Antidote:
No specific antidote
Management:
Discontinue or reduce medication
Support ventilation and circulation (Patent Airway, Oxygen, IV Fluids, Vasopressors)
Control seizures with benzodiazepines (Diazepam IV 0.05-0.2 mg/kg, Midazolam IM 0.2 mg/kg or IV 0.025-0.1 mg/kg) or Barbiturates (Thiopental Sodium IV 0.5-2 mg/kg)
Prolonged Cardio-Pulmonary Resuscitation with Cardiac Arrest IV Sodium Bicarbonate 1-2 mEq/kg to treat cardiac toxicity (sodium channel blockade), IV bretylium 5 mg/kg , DC
cardioversion/ defibrillation for ventricular arrhythmias
Remove ingested drug by induced emesis followed by activated charcoal.
Hypersensitivity reactions - Remove from further exposure. Treat dermatitis
Guidelines
(1) Do not use on eyes.
(2) To minimize systemic absorption do not apply topically to large areas of denuded or inflamed tissue.
(3) Use with caution in patients with severe disturbances of cardiac rhythm, shock or heart block.
(4) Reduce doses in obstetric, elderly, hypovolemic and high-risk patients.
(5) Cauda equina syndrome with permanent neurological deficit has occurred in patients receiving greater than 20 mg of a 1% tetracaine solution with a continuous spinal technique.
(6) There is potential for allergic reaction with repeated use.
(7) Contraindicated in patients with hypersensitivity to tetracaine or ester type local anesthetics, and patients with allergy to suntan lotion (contains PABA derivatives).
(8) The level of sympathetic blockade determines the degree of hypotension following intrathecal administration of tetracaine. Blocks above T5 affect cardiac sympathetic nerves and are associated with bradycardia and decreased cardiac output. Fluid hydration (10-20 mls/kg NS or Lactated Ringer's solution), vasopressor agents e.g. ephedrine and left uterine displacement in pregnant patients may be used for prophylaxis and/or treatment. Administer atropine to treat bradycardia.
(9) Caudal or intrathecal injections should be avoided when the patient has hypovolemic shock, septicemia, infection at the injection site or coagulopathy.
Adverse
CVS: hypotension, bradycardia, heart block, arrhythmias, peripheral vasodilation
PULM: respiratory impairment or paralysis
CNS: post spinal headache, tinnitus, seizures, blurred vision, restlessness
ALLERGIC: urticaria, erythema, angioneurotic edema
SPINAL: high spinal, loss of perineal sensation and sexual function, backache, weakness and paralysis of the lower extremities, and loss of sphincter control, slowing of labor, cranial nerve palsies, meningitis
TIZANIDINE
CLASS: (SKELETAL MUSCLE RELAXANT)
USE(S): Treatment of spasticity related to spinal cord pathology and multiple sclerosis; adjunct treatment of acute compression radiculopathy, chronic regional pain syndrome (CRPS/RSD), multiple sclerosis, trigeminal neuralgia, pre-trigeminal neuralgia, glossopharyngeal neuralgia, vago-glossopharyngeal ; neuralgia, organic (non traction) headache, neuropathic pain, post herpetic neuralgia, fibromyalgia; perioperative sedation
DOSING: Spasticity/Trigeminal neuralgia/Organic Headache/Neuropathic Pain/ Fibromyalgia/CRPS/RSD:
Initial PO: 2 mg in the morning and afternoon, 4 mg at bedtime.
Maintenance: PO 4-12 mg three times daily
For increased muscle relaxation, Tizanidine doses may be supplemented with Baclofen.
Monitoring of aminotransferase levels (ALT/SGPT, AST/SGOT) is recommended during the first 6
months of treatment (e.g., baseline, 1, 3 and 6 months) and periodically thereafter based on the clinical status. Because of the potential toxic hepatic effect of tizanidine, the drug should be used only with extreme caution in patients with impaired hepatic function.
Perioperative Sedation: PO: 4 mg . Administer 90 minutes prior to induction.
ELIMINATION: renal
PREPARATIONS:
Tizanidine (Zanaflex)
Tablets: 2 mg, 4 mg
Pharmacology
A short acting alpha-2-adrenergic receptor agonist, Tizanidine is structurally and pharmacologically similar to clonidine and other alpha-2-adrenergic agonists. However, Tizanidine has one-tenth to one-fiftieth the antihypertensive potency of these drugs. 12 mg of Tizanidine is equipotent in sedative and sympatholytic activity with 150 mcg of Clonidine. The antispasmodic activity of Tizanidine results from agonism at central pre-synaptic alpha-2- receptors. The response to agonism at these receptors is a decrease in the release of excitatory neurotransmitters (such as glutamic acid) which in turn leads to the inhibition of spinal motor neurons. Both Tizanidine and baclofen inhibit spinal interneuron firing, however Tizanidine's effects are mediated by alpha-2 receptors whereas baclofen may exert a direct effect on the polarization state of the neuron membrane. Tizanidine and baclofen are equally effective in anti-spastic activity. However Tizanidine may be associated with fewer side effects such as severe muscle weakness. Tizanidine or baclofen are the drugs of choice for muscle spasm in patients with multiple sclerosis and other spinal cord lesions, where the decrease in the number and severity of muscle spasms (especially flexor spasms), alleviates associated pain, clonus, muscle rigidity and improves mobility. Either tizanidine or intrathecal baclofen are preferable to intrathecal injections of sclerosing agents (e.g. phenol), rhizotomy or cordotomy. Tizanidine (like clonidine) mediates gastric mucosal protection and may reduce the incidence of NSAID induced gastric irritation. Tizanidine may have anti-nociceptive properties. It has been reported to relieve neuropathic (lancinating, shooting) and causalgic (hot, burning, cramping) components of phantom limb pain. Oral tizanidine may be effective in the adjunctive treatment of reflex sympathetic dystrophy, trigeminal neuralgia, fibromyalgia and nonvascular headache. Tizanidine may relieve the episodic and allodynic pain in post herpetic neuralgia. In large doses, tizanidine may produce excess sedation and hypotension.
Pharmacokinetics
ONSET OF ACTION: Antispastic effects PO: hours to weeks
PEAK EFFECT: Antispastic : PO: variable Intrathecal bolus: 4 hrs
DURATION OF ACTION: Antispastic effects : PO : variable
INTERACTIONS: Potentiates CNS depressant effects of alcohol, barbiturates, narcotics, volatile anesthetics; additive muscle relaxant effects when co-administered with baclofen.
TOXICITY:
Toxic Range:
Not routinely monitored
Manifestations:
Vomiting
Muscle hypotonia
Salivation
Drowsiness
Confusion
Blurred vision
Respiratory depression
Coma
Seizures
Elevated serum lactate dehydrogenase and AST (SGOT) concentrations
Antidote:
No specific antidote
Management:
Discontinue or reduce medication
Support ventilation and circulation (Patent Airway, Oxygen, IV Fluids, Vasopressors)
Airway protected - ipecac syrup induced emesis (30 mls or 0.5 mls/kg ipecac syrup followed by 200 mls or 4 mls/kg of water or clear fluid) or gastric lavage (with drug ingestion) followed by administration of activated charcoal (PO 50-100 grams or 1-2 gram/kg)
Symptomatic treatment
Guidelines/Precautions
(1) Tizanidine occasionally causes liver injury, most often hepatocellular in type. In controlled clinical studies, approximately 5% of patients treated with tizanidine had elevations of liver function tests (> 3 times normal). Most cases resolved rapidly upon drug withdrawal.
(2) Deterioration in seizure control may occur in epileptic patients receiving tizanidine. The EEG should be monitored periodically.
(3) Use the drug with caution in patients who must use spasticity to maintain an upright posture or balance in locomotion or whenever spasticity is utilized to obtain increased function.
(4) Abrupt withdrawal may lead to hallucinations, seizures and acute exacerbation of spasticity.
Dosage should be reduced gradually if the drug is to be discontinued, .
(5) Patients should be warned that tizanidine may impair their ability to perform activities requiring mental alertness or physical coordination (e.g. operating heavy machinery, driving a motor vehicle)
Principal Adverse Reactions
CVS: tachycardia, hypotension, palpitations, angina, syncope
PULM: dyspnea, respiratory depression
CNS: drowsiness, fatigue, vertigo, dizziness, hypotonia, mental depression, excitation, headache, hallucinations, euphoria, anxiety, dysarthria, strabismus.
GI: nausea and vomiting, constipation, diarrhea, taste disorders, abdominal pain
MUSCULOSKELETAL: muscle pain
OTHER: rash, pruritus
Reactions
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