Pain does not discriminate. It affects anyone and everyone at some point in time. In America, approximately 100 million individuals are inflicted with chronic pain. In fact, for individuals 65 and above, 50% experience chronic pain. Pain comes in all types and severities, such as acute, chronic, neuropathic, nociceptive, visceral, and somatic. Regardless of the type or severity, unmanaged pain can result in healthcare cost increases, productivity losses, and quality of life reductions. Thus, the purpose of this article is to explain pain and its management.
Pain has many definitions. Pain can be defined as “any unpleasant sensation occurring in varying degrees of severity as a consequence of injury, disease, or emotional disorder.” Pain is also defined “as whatever the experiencing person says it is, existing whenever the experiencing person says it does.” Acute pain presents with a recent onset, lasting no more than 3-6 months after initial insult is resolved. Chronic pain onsets slowly and lasts more than 3-6 months. Nociceptive pain ceases after source is healed. Examples include osteoarthritis, osteoporosis, fractures, rheumatoid arthritis. Neuropathic pain involves the central nervous system and lasts following source resolution. Examples include post herpetic neuropathy, diabetic peripheral neuropathy, herpes zoster or shingles infections.
In order to manage pain, it is imperative to understand the pain pathology. Pain begins with a stimulus. This stimulation leads to pain transmission from the spinal cord to the brain. At this level, perception occurs. Following perception, modulation begins. Modulation is the inhibition of pain impulses from the brain to the peripheral site via chemicals such as norepinephrine and serotonin. Over prolonged time, this acute pathology results in a chronic response causing central nervous system dysregulation and peripheral hyperexcitability, causing difficulty in pain management.
Managing pain requires assessment and treatment. Assessment is crucial for optimal treatment. Unfortanetly, pain is completely subjective without any true objective parameters diagnosing pain definitely. Thus, assessment includes patient history, physical exam, barriers, and the PQRSTs of pain: P: pallatative measures of those behaviors which reduce the pain, Q= pain quality, R=pain region or location, S=pain severity, and T= pain time. Once a thorough assessment is complete, treatment begins.
Both non-pharmacologic and pharmacologic treatment exists. Ideally, the treatment should be evidence based, possess minimal side effects, individualized, inexpensive, and provide maximal pain relief. The goals of pain management are overall activity improvement, sleep quality improvement, side effect avoidance, and individual goal achievement. Specific behaviors or interventions without medications include physical exercise, music listening, guided imagery, meditation, stress management, and cognitive behavioral therapy or education. However, when non-pharmacological treatment inadequately or incompletely resolves the pain, medications can be used.
The World Health Organization has developed an analgesic ladder based on pain type and severity. For mild to moderate pain, acetaminophen, ibuprofen or other non-steriodal therapies can be used. For moderate to severe pain, tramadol and hydrocodone are recommended. For severe pain, opioid therapies of morphine, hydromorphone, oxycodone, and fentanyl are recommended. In addition, add on medications are often utilized such as gabapentin, pregabalin, prednisone, amitriptyline, etc. The chosen therapy depends on individual characteristics encompassing other disease states, drug/disease or drug/drug interactions, cost, adversities, and effectiveness.
Mild to moderate pain drug therapies are typically over the counter. For example, acetaminophen and non-steroidal therapies are effective. However, as with any ingested substance, certain aspects should be considered such as drug interactions and cautions or warnings. Acetaminophen is considered the safest analgesic available. Minimal side effects and drug interactions occur with its usage. Typical dose is between 2-4 grams daily. However, with over use liver toxicity is a potential. Non-steroidal therapy also must be used with caution, especially secondary to increase gastrointestinal irritation, potential kidney toxicity, and cardiovascular involvement. Topical agents such as Aspercreme, BenGay, Sportsflex in the recommended doses often alleviate these warnings, however, are not as effective. It is advised to always discuss with physician or pharmacist prior to starting an over the counter pain reliever to evaluate risks and benefits.
Unrelieved mild-moderate pain and moderate to severe pain are treated with stronger prescription strength medications such as opoids. Weak opoids include hydrocodone and tramadol formulations. Strong opoids include morphine, hydromorphone, oxymorphone, oxycodone, fentanyl, and methadone. Opoids are extremely effective, however, there is a potential for thinking impairments leading to confusion, poor insight, drowsiness, tolerance, addiction, abuse and also nausea, and constipation. These medications are chosen as last resorts.
Often to reduce the need of the opoids, adjuvant analgesics are used. Adjuvant medications assist in multiple ways in the pain pathway. Indications for their use include nerve pain, cancer pain, fibromyalgia, and bone pain. Examples are tricyclic anti-depressants such as amitriptyline, desipramine, nortriptyline, and serotonin norepinephrine reuptake inhibitors such as duloxetine an venlafaxine an anti-convulsants such as gabapentin, pregabalin, an divalproex sodium, and topical agents such as lidocaine, and bisphosphonates such as zoledronic acide and pamidronate.
In conclusion, pain requires attention. It can be sudden or gradual. It can be mild or severe. Pain can be local or diffuse. No matter the characteristics, it cannot be ignored. The first step to treating pain is understanding its complexity and the multiple treatment regimens. This education is important for optimally individualizing the therapy for maintaining an improved quality of life.
Pharm D, BCPS, BCACP, CDE, MSMTM