Pharmacotherapy of Non-malignant pain

Erik Trimarelli, PharmD Candidate 2007

Epidemiology /
  1. Pain affects millions of people every year
  2. Nearly ½ of the population has received some sort of pain intervention
  3. About 1/3 of the population suffered from chronic pain and resulted in 700,000,000 work days lost
  4. The annual direct and indirect costs of pain in American society is approaching $100,000,000,000

DiseaseState Definition /
  1. Pain is an integral element of trauma, surgery, and many other medical procedures
  2. Pain is a conscious event that is experienced when pain signals are successfully transmitted to the
highest centers of the central nervous system
injury/disease → noxious stimulus → nociceptive impulses → stimulus reaches consciousness
  1. Pain can be classified as acute, chronic (not associated with malignancy), and malignant pain

Patho-physiology /
  1. Nocioception has 4 major components
transduction- the reception of noxious impulses at nociceptors from tissue insult/injury
transmission- the conduction of noxious impulses from site of injury toward the spinal cord
perception- the movement of nociceptive information from the spinal cord to the cerebral cortex
modulation- activation of non-nociceptive sensations which reduce the sensation of pain
  1. Nociceptors are peripheral afferent neurons that have a very thin or non-existent myelin sheath
-much more sensitive to stimuli then other afferent neurons (mechanical, propioceptive, etc…)
-types include A-delta and C fibers
  1. Transduction and transmission involve many different substances/ligands
-excitatory: substance P, prostaglandins, bradykinin, histamine, serotonin, nor-/epinephrine
-inhibatory: opioids, endocannabinoids, GABA, acetylcholine
Clinical Presentation / somatic / visceral / neuropathic
location / localized / generalized / radiating
clinical features / stabbing or sharp / deep pressure/ aching / burning/tingling
examples / superficial burns/lacerations / muscle spasm, kidney stone / diabetic/HIV neuropathy
Diagnosis /
  1. There are no diagnostic tests for pain, however X-ray, PET, and CT scanning all play a role in
aiding in diagnosis of acute/chronic pain syndromes
  1. Assessment is key in treatment/monitoring patient progress
  2. Many different scales used to assess patient pain
-visual scales
-verbal scales
-numerical scales
Treatment Options**
(Non-drug and Drug Therapy – include all therapeutic classes/agents available and preferences per treatment guidelines)
**See Treatment Options Table / see treatment options table
Monitoring
(Efficacy and Toxicity Parameters) /
  1. pain assessment score
  2. functional status
  3. behavior status
  4. adverse effects (see treatment options table)

References

1. Institute for Clinical Systems Improvement (ICSI). Assessment and management of acute pain.

Bloomington (MN): ICSI; March 2006.

2. Institute for Clinical Systems Improvement (ICSI). Assessment and management of chronic pain.

Bloomington (MN): ICSI; November 2005.

3. Lipman AG. Pain Management for Primary Care Clinicians. Bethesda (MD): American Society of Health

System Pharmacists; 2004.

4. Baumann TJ. Pain management. In: DiPiro JT et al. (eds). Pharmacotherapy: A Pathophysiologic

Approach, 6th edition, 2005, pp 1089-1104.

5. Reisner L, Koo PJ. Pain and its management. In Koda-Kimble MA, et al. (eds). Applied Therapeutics: The

Clinical Use of Drugs, 8th edition, 2005, pp.9.1-9.40.