Analgesics Flashcards
Prostaglandins mediate what?
Local inflammatory mediators
PGE2 sensitizes what?
Nerve endings to the action of bradykinin, histamine, and other chemical mediators
All NSIDs act how?
By inhibiting the synthesis of prostaglandins
What are the two conventional NSAIDs?
Acetylsalicylic Acid
Celecoxib
What is the “other” NSAID?
Acetaminophen
What is the life cycle of platelets?
7-10 days
Why is it best to discontinue NSAIDs for 2 weeks before surgery?
NSAIDs kill off platelets, so you need to allow them to regenerate before surgery
What dose of ASA is needed for analgesia?
160-325mg
What dose of ASA is needed for anti-pyretic?
160-325mg
What dose of ASA is needed for anti-inflammatory?
325-650mg
What dosing of ASA will kill platelets?
80-160mg
How/why does ASA kill platelets?
Causes irreversible inhibition of COX-1(TXA2) for the life of the platelets
What two benefits does Acetaminophen have over ASA?
No GI effects
Safe in pregnancy
What two disadvantages does Acetaminophen have compared to ASA?
No inflammatory control
No platelet inhibition (may not be an advantage…)
What is the MOA of Aspirin?
Irreversibly, non-selectively inhibits COX, reducing PG and TXA2 synthesis
What are the two common adverse effects of Aspirin?
Bleeding time doubles
Headache
What is the one hypersensitivity reaction to Aspirin?
Angioedema
What conditions cause Reye’s Syndrome?
A child with a fever from an active viral infection taking Aspirin
What three things occur in Reye’s Syndrome?
GI disturbances
Liver Degeneration
Encephalopathy
What is the rate of mortality in Reye’s Syndrome?
35%
Reye’s Syndrome can occur in kids up to about what age?
15
Aspirin reacts with what three groups of drugs?
- Ophthalmic/oral NSAIDS and Omega-3s
- Aectaminophen and Cyclosporine
- Steroids
What is the result of an Aspirin and NSAID/Omega-3 interaction?
Hemorrhage risk - additive
What is the result of an Aspirin and Acetaminophen/cyclosporine interaction?
Nephrotoxicity - additive
What is the result of an Aspirin and Steroid interaction?
GI toxicity - additive
What are the 5 contraindications associated with Aspirin?
- Hemorrhagic disorders
- Pregnancy, esp. 3rd trimester
- Corneal denervation/dry eye
- NSAID/ASA induced asthma
- Chronic GIT inflammation/active peptic ulcer
What are the two indications for Acetaminophen?
Mild pain
Fever
What is the MOA of Acetaminophen for the analgesic effect?
Inhibits COX and enhances 5-HT release
What is the MOA of Acetaminophen for the antipyretic effect?
Acts centrally at the hypothalamus by inhibiting PG synthetase
Acetaminophen only inhibits inflammation where?
Centrally - not peripherally
What are the 3 common side effects of Acetaminophen?
Nausea
Rash
Headache
What are the 3 serious adverse effects of Acetaminophen?
Acute hepatotoxicity
Acute renal tubular necrosis
Chronic analgesic nephropathy
What are the three categories of drugs that interact with Acetaminophen?
Acetaminophen/antihitstaminic combos
ASA
Lidocaine Topical
What is the effect of the interaction of Acetaminophen with acetaminophen/antihistaminic combos?
Hepatotoxicity - additive
What is the effect of the interaction of Acetaminophen with ASA?
Nephropathy - additive
What is the effect of the interaction of acetaminophen with topical lidocaine?
Methemoglobinemia - additive
What are the 4 indications for Celecoxib?
Arthritis
Ankylosing Spondylitis
Dysmenorrhea
Acute pain
What is the MOA of Celecoxib?
Selectively inhibits COX-2 and reduces PG synthesis
What is the common adverse effect of Celecoxib?
Headache
What are the 3 cardiovascular black box warnings of Celecoxib?
Stroke
Myocardial infarction
Congestive heart failure
What are the 2 GI black box warnings for Celecoxib?
Bleed
Ulceration/perforation
Celecoxib contains what moiety?
Sulfonamide
What are the two drug categories that interact with Celecoxib?
NSAIDS (esp Ketorolac)/Corticosteroids
Azoles
What is the effect of the interaction of NSAIDs/Corticosteroids with Celecoxib?
Hemorrhage
What is the effect of the interaction of Celecoxib with Azoles?
Impaired metabolism (buildup of celecoxib)
What is the contraindication to Celecoxib?
Sulfonamide allergy
What does neurogenic pain respond best to?
Anticonvulsants or antidepressants
What type of drug is the drug of choice for severe chronic malignant/nonmalignant pain?
Opioids
What FDA class do narcotics belong to?
II
What is the MOA of Hydrocodone?
Inhibit adenylyl cyclase activity
Enhance K+ outflow to hyperpolarize nerves affecting neuronal excitability and muscle tone
Stimulates prolactin and growth hormone release
What receptors does Hydrocodone act through?
G-protein-coupled Mu, Kappa and delta “opioid” receptors
Where does hydrocodone act, centrally or peripherally?
Centrally
What are the 6 common adverse effects of Hydrocodone?
Lightheadedness Dizziness Sedation Miosis Puritis Flushing
Why might Hydrocodone cause flushing?
Histamine release
What are the 3 cardiovascular adverse effects of Hydrocodone?
Bradycardia
Tachycardia
Orthostatic hypotension
What are the 3 CNS adverse effects of Hydrocodone?
Drowsiness
Mood changes
Elevated intracranial pressure
How long does it take for drowsiness to kick in with hydrocodone use?
About 1 week
With Hydrocodone use, are mood changes quick to occur, or slow to occur?
Quick tolerance
With Hydrocodone use, what causes pupillary miosis?
Excitatory action on the parasympathetic nerve to the iris sphincter
What are the 3 drugs that interact with Hydrocodone?
Anticholinergics
Classic Antihistamines
Carbonic Anhydrase Inhibitors
What occurs in the interaction of Hydrocodone and Anticholinergics?
Constipation/paralytic ileus - additive
What occurs in the interaction of Hydrocodone and Classic Antihistamines?
CNS depression - additive
What occurs in the interaction of Hydrocodone and CAIs?
CNS toxicity - additive
What is the contraindication for Hydrocodone?
Mydriatic procedures - antagonizes
What is the Non-Conventional opioid?
Tramadol
What is the indication for tramadol?
Moderate/severe pain
What is the MOA of Tramadol?
Mu receptor agonist - effect is greater with active metabolite
Weak inhibitor of Ne/5-HT reuptake
What does NE stand for?
Norepinephrine
What is 5-HT?
Serotonin
What are the 3 common adverse effects of Tramadol?
Headache
Puritis
Flushing
What is the CNS adverse effect of Tramadol?
Serotonin syndrome
What is the cardiovascular adverse effect of Tramadol?
Orthostatic hypotension
What are the 3 classes of drugs that interact with Tramadol?
Anticholinergics
Classic antihistaminics
Azoles
Tramadol antagonizes which ACh receptors?
Both muscarinic and nicotinic
Migraines are what kind of disorder?
Neurovascular
Up to 1/3 of patients with migraine experience what?
Visual aura
High levels of what are associated with migraines?
Serotonin
What signs are associated with the prodromal phase of a migraine?
Arterial vasoconstriction
Release of serotonin
What signs are associated with the headache phase of migraines?
Cerebral vasodilation
Lower than normal levels of serotonin
What is the top prophylactic migrane drug class?
Topiramate
What are the two classes of abortive drugs for migraines?
Triptans
Ergotamines
What are the 2 indications for Sumatriptan?
Acute migraines
Cluster headaches
What is the MOA of Sumatriptan?
Selectively activates vascular serotonin 5HT-1 receptors, causing intracranial vasoconstriction
Stimulates neuronal serotonin receptors, decreasing the release of peptides including Substance P and CGRP
What is the common adverse effect of Sumatriptan?
Dizziness
What is the 1 hypersensitivity to Sumatriptan?
Angioedema
What are the 2 ocular adverse effects of Sumatriptan?
Partial vision loss
Transient/permanent blindness
What is the 1 caution for Sumatriptan?
Hypertension (it causes vasoconstriction)
What are the 2 indications for Ergotamine?
Migraine
Cluster headache
Ergotamine is structurally similar to what?
Biogenic Amines
What is the MOA of Ergotamine?
Stimulates serotonin receptors producing intracranial vasoconstriction, and inhibition of CN-V pain transmission
What is the 1 adverse effect of Ergotamine?
Photosensitivity
What are the 4 drug types that inhibit ergotamine metabolism?
Macrolides
Azoles
Fluoroquinolones
Cyclosporine
What happens when tetracyclines interact with Ergotamine?
May increase risk of Ergot toxicity
What happens with Ergotamine interacts with Timolol?
Peripheral vasoconstriction is enhanced
What are the 2 indications for Topiramate?
Migraine prophylaxis
Seizures
What requires a higher dose of Topiramate, migrain prophylaxis, or seizures?
Seizures
What is the MOA of Topiramate?
Blocks voltage-gated Na channels
Augments GABA activity
Antagonizes glutamate receptors
Inhibits CAI
What are the 5 common adverse effects of Topiramate?
Bleeding
Nystagmus
Diplopia
Visual disturbance
What are the 5 serious adverse effects of Topiramate?
Angle closure glaucoma Myopia Maculopathy Hemorrhage Anemia
What may occur when Topiramate interacts with CAIs or Steroids?
Hypokalemia - additive
What may occur when Topiramate interacts with Gluoroquinolones?
QT prolongation
What may occur when Topiramate interacts with Opioids or classic Antihistamines?
Increased risk of CNS depression
What is the 1 caution for Topiramate?
Hemorrhage