Contraindications for opioidsIn palliative care, opioids are not recommended for sedation or anxiety because experience has found them to be ineffective agents in these roles. Some opioids are relatively contraindicated in renal failure because of the accumulation of the parent drug or their active metabolites (e.g. morphine and oxycodone). Age (young or old) is not a contraindication to strong opioids. Some synthetic opioids such as pethidine have metabolites which are actually neurotoxic and should therefore be used only in acute situations."

Two basic categories of Pain

nociceptive pain: results from mechanical, thermal, or chemical activation of nociceptive afferent receptors and can be classified as either somatic(skin, muscles, fascia and bones) ex. cavity preparation and periodontitis; or visceral origin which is poorly localizedcan be referred to as superficial somatic areas, but involves pathologic conditions in deep visceral tissues. EX. pain from angina resulting from myocardial ischemia can be referred to in the jaw,neck or arm (Yagiela 764).

neuropathic pain : results from somatosensory activity either in the peripheral nervous system or in the central nervous sysytem
charactorized by paroxysmal shooting or electrical shocklike pain, often on a background of burning or constricting sensations EX. the pain associated with trigeminal neuralgia and posttherpetic neuralgia requires more specific testing(Yagiela 764).

Acute Pain has been known to be caused by tissue damage, gets better as healing takes place, has a predictable endpoint.
associated with anxiety, and the flight or flight response that increases pulse and respiratory rates(Yagiela 764).

Chronic Pain pain that lasts longer than 3-6 months and usually do not manifest the physiologic arousal of the fight or flight response because the body has already adapted to the pain. They may show signs of reactive depression and decreased function(Yagiela 764)..

The roles of pain facilitatory systems in opioid toleranceby Hsu MM, Wong CS Department of Anesthesiology, Tri-Service General Hospital & National Defense Medical Center, Taipei, Taiwan, R.O.C. Acta Anaesthesiol Sin 2000 Sep; 38(3):155-66 ABSTRACT

Opioids are powerful analgesic agents and have been widely used in clinical pain management for decades. Nevertheless, both acute and chronic opioids administration may produce tolerance, as indicated by a lowered responsiveness to the drugs at a later time. Koob and Bloom described two possible mechanisms of drug tolerance: a within-system and a between-systems adaptation. Opioid receptors uncoupling from G-proteins and receptor down-regulation, in particular the receptor's high affinity sites, are well-known mechanisms (the within-system) of opioid tolerance. A series of recent studies have proposed that a between-systems, particularly the pain facilitatory systems (opiate-activated opponent systems), may also involve in the development of opioid tolerance. Several lines of evidence suggest that N-methyl-D-asparate (NMDA) receptors activation and the subsequent nitric oxide (NO) production probably play a between-systems mechanism of opioid tolerance. Recently, our and others' studies also found that cyclooxygenase (COX) inhibitors could attenuate the opioid tolerance without enhancing morphine's antinociceptive effect. Taking all these findings together, the pain facilitatory systems included the NMDA-receptors, NO, and COX systems may also play important roles in opioid tolerance. In summary, except the opioid receptor uncoupling and opioid receptor down-regulation, chronic morphine treatment may also activate pain facilitatory systems (NMDA receptor activation, NO production, and COX ac-tivation) during opioid tolerance development. It implies that some complicated interactions may happen among the opioid receptor, NMDA-receptor, NO, and COX systems and are worth further investigations.


Diuretics help the kidneys eliminate excess salt and water from the body's tissues and blood.

  • Loop Diuretics
  • Thiazide diuretics
  • Thiazide-like diuretics
  • Potassium sparing Diuretics