Cite article. Most drugs act by binding to protein targets on cell membranes and affecting the biochemical processes of the body.
Protein targets are specific to specific tissues allowing drugs to be precisely targeted at individual organs or cells. Drugs exhibiting high specificity require lower doses and have fewer side effects than those with lower specificity. Originally developed by the World Health Organisation WHO to improve management of cancer pain; the 3 step WHO analgesic ladder is also used for providing stepwise pain relief for pain due to other causes. Compound analgesics are a combination of drugs in a single tablet usually including codeine a weak opiate and aspirin or paracetamol.
Co-codaprin is a combination of codeine phosphate 8mg with aspirin mg. Tramaset contains a low dose NSAIDs, paracetamol and opioids decrease pain via different mechanisms so used together can improve pain relief.
Medications containing codeine may cause side effects including nausea, vomiting, constipation and drowsiness  with particular implications for people who need to drive or operate machinery as part of their day to day role. They work in the central nervous system by binding to opioid receptors in the pre- and post-synaptic membrane stopping the passage of neurotransmitters across the nerve synapse which blocks or attenuates the experience of pain.
Opioid medications include morphine, oxycodone, codeine, tramadol, buprenorphine, fentanyl and diamorphine heroin. With either route slow or modified release preparations are often used to minimise fluctuations in pain relief and reduce the number of tablets that need to be administered. Examples of slow or modified release medicines which work over 12 or 24hrs include tramadol preparations such as Zydol or Zamadol . Fentanyl and Buprenorphine may be administered via transdermal patches which are applied every few days.
Opioid receptors are present in tissues throughout the body and the interaction of the drugs with these receptors is responsible for the side effects associated with opioid medications. In the GIT these include nausea and vomiting and, as a result of decreased gut motility, constipation. Opioids also reduce the sensitivity of the respiratory centres in the brain stem to CO2 leading to respiratory depression.
Insight into Pain Modulation: Nociceptors Sensitization and Therapeutic Targets
Other effects include drowsiness and dizziness and prolonged use can lead to hormonal changes which can lead to reduced libido, infertility and depression . The use of opioids for chronic non-cancer pain is controversial. So, techniques using touch, such as manual therapy, are not always the best first choice. Active techniques, on the other hand, that is, those performed by the patient with or without physical therapist help, have long-term analgesic effects.
Some patients may take months to feel the analgesic effects. Keeping the example of the exercises, it is known that they are a modulation source, especially in people performing regular exercises 16, Exercises, in addition to releasing analgesic substances, promote functional autonomy. For patients with major limitations, function gain encourages the change of abnormal pain-related behaviors, increasing self-efficacy, motivation, well-being and satisfaction. On the other hand, the association of the exercise to pain or injury favors behaviors such as avoidance and fear, kinesiophobia, isolation and immobility 28,29,34, Physical therapists should be educator therapists, regardless of choosing passive or active techniques Education strategies to fight dysfunctional beliefs, abnormal behaviors, negative thoughts and attitudes are able to modulate pain and increase functional capacity of patients 27, Associated to other cognitive behavioral techniques, such as pacing of activities, they encourage patients to be active participants of their healthcare, being able to understand chronic pain, its impact on health and recover pain control 27,33, All physical therapy techniques have placebo effect.
Authors believe that the explanations for the analgesic mechanisms of the placebo effect are more related to the classic conditioning role and to psychological factors. Among explanations, there are expectations and positive beliefs about efficacy and symptoms relief, decreased anxiety and desire to improve. Authors discuss the associated opioid substances release 25, The placebo effect is still a mystery for physical therapists, however patients may benefit for a short period of time. It is important to remember that physical therapists are prohibited to use the placebo effect in their clinical practice.
Attention and concern with patients' health status, combined with the desire to improve, optimism and the way to deal with pain are independent effects of physical therapy techniques 26, The best result for pain management is expected when there is integration among physical modalities, cognitive behavioral approaches such as education, and with the help of other health professionals 27,33, Different mechanisms and effects may be influenced by physical therapy physical and cognitive behavioral techniques, contributing for the treatment of painful patients and helping the choice of techniques based on identified clinical mechanisms.
The integration of pain science into clinical practice.
J Hand Ther ;10 2 Kumar SP, Saha S. Mechanism-based classification of pain for physical therapy management in palliative care: A Clinical Commentary. Indian J Palliat Care ;17 1 Nijs J, Van Houdenhove B. From acute musculoskeletal pain to chronic widespread pain and fibromyalgia: application of pain neurophysiology in manual therapy practice. Man Ther ;14 1 Smart K, Doodyb D.
Mechanisms-based clinical reasoning of pain by experienced musculoskeletal physiotherapists. Physiotherapy ;92 3 Moseley L.
A pain neuromatrix approach to patients with chronic pain. Man Ther ;8 3 Pain, mind, and movement. Clin J Pain ;24 4 Pain exposure physical therapy may be a safe and effective treatment for longstanding complex regional pain syndrome type 1: a case series. Clin Rehabil ;23 12 Algafly A, George K. The effect of cryotherapy on nerve conduction velocity, pain threshold and pain tolerance.
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Br J Sports Med ;41 6 Central hypersensitivity in chronic pain: mechanisms and clinical implications. McConnell J. A novel approach to pain relief pre-therapeutic exercise. J Sci Med Sport ;3 3 Menthol: a natural analgesic compound. Paradigm shift in manual therapy? Evidence for a central nervous system component in the response to passive cervical joint mobilisation. Man Ther ;13 5 Joint manipulation reduces hyperalgesia by activation of monoamine receptors but not opioid or GABA receptors in the spinal cord. Pain ; Petersen-Felixa S, Curatolob M.
Neuroplasticity: an important factor in acute and chronic pain. Swiss Med Wkly ; The effect of physical therapy on beta-endorphin levels.
The search for novel analgesics: targets and mechanisms
Eur J Appl Physiol ; 4 Souza JB. Rev Bras Med Esp ;15 2 Rev Dor ;7 1 The initial effects of knee joint mobilization on osteoarthritic hyperalgesia. Man Ther ;12 2 Hypoalgesic and sympathoexcitatory effects of mobilization with movement for lateral epicondylalgia. Phys Ther ;83 4 Chronic back pain is associated with decreased prefrontal and thalamic gray matter density. Holdings In. Gerstein Science. Subjects subject. Analgesics--therapeutic use.
Pharmacology in Pain Management - Physiopedia
Drug Delivery Systems. Receptors, Drug--physiology. More Details added author. Cairns, Brian E. Walder, Christopher J. A Look Inside Reviews. This item was reviewed in:. To find out how to look for other reviews, please see our guides to finding book reviews in the Sciences or Social Sciences and Humanities. Bowker Data Service Summary. This work reviews the role of peripheral receptor mechanisms in the transduction of pain, providing a framework for the development of new and effective rationally-designed analgesic drugs and therapies.
It brings together in one text the diverse body of work on peripheral receptor mechanisms of pain. A unique reference on peripheral pain receptor mechanisms While considerable advances have been made on pharmacotherapies for many chronic disease states, options available to treat chronic pain have remained relatively unchanged for decades. However, utilizing the receptors involved in peripheral pain transduction mechanisms offers a significant opportunity to create novel therapies for pain.