pharmacotherapy of pain
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Pharmacotherapy of pain. Acute pain preventive function localised has vegetative sympthomatology and doesn´t cause severe psychological changes clearly defined beginning and ending analgesics are usually effective in treatment. Chronic pain without preventive function lasts 3-6 months

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types of pain 1
Acute pain

preventive function

localised

has vegetative sympthomatology and doesn´t cause severe psychological changes

clearly defined beginning and ending

analgesics are usually effective in treatment

Chronic pain

without preventive function

lasts 3-6 months

often associated with severe psychological changes

without clearly defined beginning

malignant (caused by cancer)or non-malignant

Types of pain 1
types of pain 2
Types of pain 2
  • Nociceptive
    • somatic
      • superficial
      • deep
    • visceral (diffuse)
  • Neuropatic
    • central
      • deafferentational
    • peripherial
      • neuropaties
  • Idiopatic
  • Psychogenic
therapy of pain
Therapy of pain
  • Analgesics and co-analgesics
    • Non-opioid analgesics
      • Analgesics/antipyretics
      • Non-steroidal anti-inflammatory drugs

(NSAIDs)

    • Opioid analgesics
      • Natural (morphine, dihydrocodeine)
      • Synthetic (fentanyl, buprenorphine)
    • Co-analgesics(Antidepressants, Anxiolytics, Myorelaxants, Anticonvulsives, Neuroleptics, Glucocorticoids, Anesthetics, 2 sympaticomimetics, H1 antihistamines)
non opioid analgesics
Non-opioid analgesics
      • Analgesics/antipyretics
    • aspirin (acetylsalicylic acid- ASA)
    • paracetamol (USA- acetaminophen)
    • metamizole (textbooks from the US say it´s an NSAID)
  • Non-steroidal anti-inflammatory drugs (NSAIDs)
    • Non-selective inhibitors of COX-1 and COX-2 (ibuprofen, diclofenac, ASA)
    • Preferential inhibitors of COX-2 (nimesulide, meloxicam)
    • Selective inhibitors of COX-2 (celecoxib, rofecoxib (dereg.))
paracetamol
Paracetamol

Derivate of anilin

  • Mechanism of action – unknown, possibly

inhibition of COX-3 (variant of COX-1) in CNS

  • Good absorption from GIT
  • Biological half life - 1,5-3 h 
  • Only a small percentage of the drug binds on plasma proteins (10%)
  • Elimination – through the kidnies in the form of glukuronides and sulfates
  • In doses over 5 g/day can cause hepatal damage
  • In the world, approximately 200 different preparates containing paracetamol are being used.
metamizole
Metamizole

Derivate of pyrazolone

  • Synonyms Noramidopyrín, Dipyrón
  • has spasmolytic properties.
  • Serious adverse effect is depression of bone marrow leading to agranulocytosis.
  • Good absorption in the case of both peroral and rectal administration.
  • More than 50 % binds onto plasmatic proteins
  • Plasmatic halflife is short (i.v. metamizole - 14 min)
  • Elimination- mostly through kidnies.
slide12

Properties

Cyklooxygenase 1

Cyklooxygenase 2

Localisation

cytoplasmatic in ER

perinuclear

Regulation

constitutional

inducable / constitutional

Presence intissues

GIT mucosa, renal parenchyma, endothelium, Tr

Mf, Mo, CNS, kidneys, uterus, seminiferous

Predicted function

Integrity of stomach mucosa, kidney perfusion, Tr function

Patogenesis of inflammation andgenesis of pain

non steroidal anti inflammatory drugs
Non-steroidal anti-inflammatory drugs

Division according to COX selectivity:

effects of nsaids
Effects of NSAIDs
  • Analgesic effect
  • Antipyretic effect
  • Antiflogistic effect (mainly higher doses)
  • Antiaggregatory effect (not every NSAID, most important is ASA because of irreversible blocade of COX-1- be careful with combination of ASA for anti-aggregation and other NSAIDs- mostly ibuprofen)
  • Other effects- for example reduced incidence of some tumors (for example colorectal carcinoma), uricosuric effekt ...
slide15

NSAIDs– oneofthe most widelyuseddruggroups→theirADRsrepresent a seriousmedical / publichealth / economicalproblemthere are big differencesbetweenvariousNSAIDsin thelevel risk ofparticularpossibleADRs

adverse effects of nsaids
Adverse effects of NSAIDs
  • GIT- erosions and ulcersofthegastricmucosa (also in otherlocalisationsinthe GIT), nausea, vomitus, meteorism, diarrhoea, constipation... (mainlyinhibitionof COX-1)
  • kidney-reductionofglomerularfiltration, retentionof Na and fluids, edema, hyperkaliemia, kidneyfailure, interstitialnephrits...(inhibitionof COX-1 and 2)
  • CVS-thromboticevents, increaseofbloodpressure, heartfailure...(mainly COX-2 (mostly in thromboticevents))
  • CNS- cephalea, weakness, sleapdisorders, dizziness, epilepticseizures...
  • other- hepatotoxicity, bleeding, provocationofasthmaticattack, Ray´ssyndrom, prolongedchildbirth, urticaria, decreasednumberofwhitebloodcells...
gastrointestinal adrs
Gastrointestinal ADRs

most serious – ↓ productionofprostaglandins in thegastricmucosa→ pepticulcer(most often in thestomach and duodenum; themucosacan get damaged by NSAIDsalso in otherplacesinthe GIT)

roughly 25 % ofchronic NSAID usersmightdeveloperosions and ulcers, in 2-4 % perforation or bleedingcanoccure

kidney adrs
Kidney ADRs

Decreasedproductionofprostanoids→negativeeffect on theperfusionofthekidneys, glomerularfiltration, excretionofsodium and waterand on productionofrenin→circulationoverload, oedemas, hypertension ; hyperkalemia; in severe casessymptomsofacutekidneyfailure

seriouscomplication– interstitialnephritis(immunologicalreasons)

IncidenceofkidneyADRsispoughly 18%, severe cases- roughly 1%

cardiovascular adrs
Cardiovascular ADRs
  • Increasedbloodpressure- mostly in hypertensivepatientstreatedwithantihypertensives (mainlyACEIs, ARBs, beta blockers), there are big differencesbetweenvariousNSAIDs
  • Development/worseningofheartfailure- the risk ishighestduringthefirstweeksoftreatment, mainly in patientswithpreexistingcongestiveheartfailure; possibly 19% ofallcasesofcongestiveheartfailurecouldbecaused (atleastpartially) by NSAID therapy
  • Thromboticevents- acutemyocardialinfarction, stroke, thromboembolicdisease
opioid analgesics
Opioid analgesics
  • Strong agonists: morphine, fentanyl

Weak agonists: tramadol, codeine

Partial agonists: buprenorphine

Agonists/antagonists: butorfanol, pentazocine

Antagonists: naloxone, naltrexone

  • Dampen strong somatic and visceral pain – strongest analgesics, without roof effect, can cause addiction
  • Dampen algognostic (perception and localisation) and algotymick(psychical and emotional) part of pain
pharmacological effects
Depressory

Analgesia

Depression of breathing

Antitussive effect

Decreased secretion and motility in the GIT – constipation

Sedation

Stimulatory

Vomiting

Miosis

Increased tonus of smooth muscles, sphincters

Induction of histamine release

Euphoria

Pharmacological effects
adverse effects of opioids
Adverse effects of opioids

Neuropsychiatric

  • Sedation, clouded consciousness, euphoria, sleep disorders

Cardiopulmonal

  • Depression of breathing, Bronchoconstriction (high doses) Orthostatic hypotension, Bradycardia (high doses)

Gastrointestinal

  • Nausea, vomiting, constipation, gastrointestinal or gallbladder colics

Urinary system

  • Retention of urine

Endocrine

  • Decreased levels of testosterone, problems with menstrual cycle

Allergic and immunologic

  • Pruritus, immunosupression
morphine
Morphine

Prototypical opioid

  • Isolated from sap from unriped skulls of poppy (1803)
  • Fast resorption after p.o. application, bioavailabilityis only 30% (significant first pass effect)
  • Most common adverse effects- nausea, vomiting, constipation, gallbladder and uretral spasms
  • Depression of breathing is the most common cause of death in case of intoxication.
  • Most common signs of intoxication – unconstiousness, bradypnoea a miosis
fentanyl
Synthetic derivate of phenylpiperidine

Strong agonist of  receptors

80-100 times more potent than morphine

Lipophilic character – rapid onset of action, but the effect lasts only for a short time

Contraindicated in pregnancy

Derivates of fentanyl- sufentanyl and alfentanyl are used in anesteziológii

Big advantage – availability of fentanyl in the form of transdermal patches – „Durogesic“

The second most widely used opioid

Fentanyl
tramadol
Tramadol

Atypical opioid

  • Intermediate analgesic effect
  • High bioavailability is an advantage.
  • In therapeutic doses lacks most of the adverse effects of opioids.
  • The most common adverse effects are sweating, nausea and dry mouth.
  • Suitable for treatment of mild to severe pain in adults and children.
  • Available in different drug forms.
  • It is cheap.
slide27

In case of long term treatment, analgesics should be administered regularly, not only when the patient feels pain.

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