Pain Management: Individualized Therapy Is Key

More than 100 million Americans experience pain each day, and it has been associated with a $500 billion economic burden in the United States.¹ Pain is defined as a subjective and unpleasant warning mechanism that is associated with actual or perceived tissue damage or danger.² Due to its subjectivity, pain can be difficult to objectively describe or evaluate.

Types of Pain

Pain is categorized based on its duration, location, and clinical presentation. Table 1^2-5 depicts the type of pain based on duration. It can also be classified based on its location and symptoms (Table 2^2-5).

Pain is commonly rated by patients using a 0-to-10 scale, with 0 signifying “no pain” and 10 signifying “the worst imaginable pain.” Generally, mild pain would be considered 0 to 2; moderate pain, 3 to 5; and severe pain, 8 to 10.^2-7

Pain Assessment

Online Table 3 provides a user-friendly checklist for assessing a patient’s pain.

Table 3: PAINED Checklist to Ask Patients

Place

Where is the pain in your body?

Amount

Using a scale of 1 to 10, please rate your pain, with 1 being no pain and 10 being the worst pain. How often has this pain occurred?

Intensifiers

What makes the pain worse?

Nullifiers

What reduces the pain for you?

Effects

What were the adverse effects of using those past resources to reduce your pain?

Descriptors

What type of pain is it? (eg, sharp, stabbing, burning, dull, achy)

^{Adapted from reference 4}

Pain Management

Pain management should be individualized for each patient. Common nonpharmacotherapy options include application of heat or cold, massage, and cognitive behavioral therapy.^2-5

The Figure⁴ shows the general sequence of pain management. Medication selection should be based on a patient’s overall pain type/diagnosis, previous medication use, age, organ function (eg, liver function), and other drug factors (Online Tables 4-7). Topical/transdermal agents (eg, capsaicin, lidocaine, clonidine) can also be added.^2-5

Table 4: Common Nonopioid Oral Analgesics

Drug

Clinical Pearls

Acetaminophen

Recommended as first-line therapy for various somatic pain-related disease states (eg, osteoporosis). However, it is associated with hepatotoxicity, especially when taken by heavy alcohol users and with other hepatotoxic agents (eg, isoniazid, zidovudine).

Acetylsalicylic acid (aspirin)

Associated with precipitating asthma symptoms in patients who are sensitive to aspirin and the development of Reyes syndrome in pediatric patients.

Ibuprofen (NSAID)

Seen as first-line therapy for cancer-related bone pain and chronic lower back pain. NSAIDs are commonly associated with gastrointestinal, cardiac, and renal adverse effects and should be used with caution. NSAIDs may be combined with a proton pump inhibitor, H₂-receptor antagonist, or prostaglandin analog to decrease the risk of gastrointestinal bleeding.

Naproxen sodium (NSAID)

Celecoxib (COX-2 Inhibitor)

Associated with an increased risk of cardiovascular events, but is associated with fewer gastrointestinal and renal adverse effects than NSAIDs.

^{NSAID = nonsteroidal anti-inflammatory drug.Adapted from references 2-5}

Table 5: Common Oral Adjuvant Analgesics

Drug

Clinical Pearls

Gabapentin

Both agents are considered first-line therapy for neuropathic pain (eg, diabetic neuropathy) and adjuvants for nonopioid/opioid pain. Pregabalin also has been shown to be effective for fibromyalgia.

Pregabalin

Amitriptyline

Considered second-line therapy for neuropathic pain adjuvant therapy for nonopioid/opioid therapy. They should be used with caution in patients with cardiovascular disease or risk factors; nortriptyline or desipramine are the preferred agents in such patients. Use is generally avoided in the elderly population.

Nortriptyline

Desipramine

Duloxetine

Considered second-line therapy for neuropathic pain as adjuvant therapy.

Venlafaxine

Desvenlafaxine

Dexamethasone

Prednisone and dexamethasone are considered therapeutic for patients with neuropathic pain related to nerve infringement.

Prednisone

Baclofen

Useful as muscle relaxants in addition to pain relief.

Tizanidine

Tramadol

Tramadol is effective for managing moderate to severe pain and neuropathic pain. Tapentadol is effective for acute pain and diabetic neuropathic pain. Both drugs have been associated with increasing the risk for seizures.

Tapentadol

Carbamazepine

Useful in patients with trigeminal neuralgia and other neuropathies.

Valproate

Useful for treating migraine headaches and neuropathic pain.

Topiramate

Both drugs are useful for treating diabetic neuropathy and other neuropathies.

Lamotrigine

^{Adapted from references 2-5, 8.}

Table 6: Opioids and Centrally Acting Oral Analgesics

Drug

Equianalgesic Oral Dose

Clinical Pearls

Morphine

30 mg

At high doses, patients may experience increased anxiety or restlessness.

Meperidine

300 mg

Dosing should be monitored due to an increased risk of CNS irritability and myoclonic seizures.

Levorphanol

Variable

Because of the drug’s prolonged half-life, the dose may have to be reduced to prevent drug accumulation.

Hydromorphone

7.5 mg

In the elderly, the drug is associated with less cognitive impairment than morphine.

Methadone

Variable

Because of the drug’s prolonged half-life, the dose may need to be continuously altered to prevent drug accumulation.

Oxymorphone

10 mg

Associated with less emesis and sedation than morphine.

Oxycodone

15 to 30 mg

Available in immediate and controlled-release forms and in combination with other nonopioids.

Fentanyl

Variable

Associated with a less hypotensive effect than morphine or hydromorphone.

Codeine

200 mg

Converted to morphine via CYP2D6; therefore, coadministration with inhibitors/inducers should be avoided.

Hydrocodone

30 to 45 mg

Converted to hydromorphone via CYP2D6; therefore, administration with CYP2D6 inhibitors/inducers should be avoided.

Tramadol

120 mg

Associated with producing CNS excitation or sedation in patients.

^{CNS = central nervous system.Adapted from references 2-5.}

Table 7: Counseling Tips

Continuously monitor for pain relief and adverse effects and make adjustments in drug selection, doses, routes of administration, and dosing frequency for safe and effective patient management.

Discuss nonpharmacotherapy pain options (eg, massage, heat/cold application,) as adjunctive therapy to pharmacotherapy.

If patients are taking opioids, provide counseling on the adverse effects (eg, respiratory depression, CNS irritability, hypotension).

Ask patients to disclose all their medications and dietary supplements. Some medications or dietary supplements may interact and significantly affect the metabolism of certain pain medications (eg, codeine).

^{Adapted from references 2-5, 8.}

Mohamed Jalloh, PharmD, is an instructor at Creighton University and a community pharmacist at Walgreens.

References

• Institute of Medicine. Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. Washington, DC: The National Academic Press, 2011.
• Merskey H. Taxonomy and classification of chronic pain syndromes. In: Benzon HT, Rathmell JP, Wu CL, et al, eds. Raj, Practical Management of Pain. Philadelphia, PA: Mosby, 2008:13Benz.
• Sutton S. Pain management. In: Sutton S, ed. McGraw-Hill’s NAPLEX Review Guide. 2nd ed. New York, NY: McGraw-Hill; 2014.
• Scullion B, Ryan L. Chapter 45: pain management. In: Attridge RL, Miller ML, Moote R, Ryan L, eds. Internal Medicine: A Guide to Clinical Therapeutics. New York, NY: McGraw-Hill; 2013.
• Baumann TJ, Herndon CM, Strickland JM. Chapter 44: pain management. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey L, eds. Pharmacotherapy: A Pathophysiologic Approach. 9th ed. New York, NY: McGraw-Hill; 2014.
• Alschuler KN, Jensen MP, Ehde DM. Defining mild, moderate, and severe pain in persons with multiple sclerosis. Pain Med. 2012;13(10):1358-1365.
• Pain assessment scales. National Initiative on Pain Control website. painedu.org/Downloads/NIPC/Pain%20Assessment%20Scales.pdf. Accessed October 1, 2015.
• Chronic pain management. Lexi-Drugs, Lexicomp website. http://online.lexi.com. Accessed October 1, 2015.