Pain Control: Using Nonprescription Analgesics

For anyone who is experiencing pain, finding relief is a top priority. Pain is thought to be the condition most commonly treated with the use of nonprescription drugs.¹ The various nonprescription analgesics available are frequently utilized for the treatment of headaches, fever, colds, flu, toothaches, arthritis, musculoskeletal injuries and disorders, and menstrual cramps.

Currently, available oral nonprescription analgesics include acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs) (ibuprofen and naproxen), and salicylates (aspirin, magnesium salicylate, and sodium salicylate). Topical analgesics include menthol, camphor, capsaicin, and trolamine salicylate. Nonprescription analgesics are available in both brand and generic formulations in tablets, capsules, gelcaps, powders, creams, ointments, suppositories, sprays, and patches.

While nonprescription analgesics are generally safe and effective treatments when used as directed, their use has been associated with certain risks and adverse effects. There is a common misconception among many consumers that OTC drugs are harmless because they are readily available without a prescription; however, acetaminophen (APAP), one of the most commonly used OTC analgesics, is the leading cause of acute liver failure in the United States.^2,3 Furthermore, more than 50% of APAP-related acute liver failure cases are due to unintended chronic overdoses.² Factors responsible for APAP-induced acute liver failure include repeated dosing in excess of recommended doses, using multiple products that contain APAP, and use of alcohol.2 The FDA reports that some patients typically take more than the recommended dosage, which increases the potential for adverse reactions.4 Pharmacists can be very instrumental in assisting patients in the proper selection and use of nonprescription analgesics. Selection of nonprescription analgesics should be based on a careful assessment of a patient’s medical and medication profile as well as their allergy history. An estimated 20% to30% of patients over the age of 65 years take analgesics daily.^5,6 It is particularly important that this older patient population be educated about the safe use of analgesics because they are more likely to take prescription medications, which could result in drug interactions or contraindications.^4-6

To increase awareness about the safe use of OTC analgesics, the FDA launched a national education campaign to provide guidance to patients. More about this campaign can be found at http://www.fda.gov/Drugs/ResourcesForYou/Consumers/ BuyingUsingMedicineSafely/UnderstandingOver-the-CounterMedicines/SafeUseofOver-the-CounterPainRelieversandFeverReducers/ucm164977.htm.

Acetaminophen

While APAP is considered to be an effective and safe analgesic/antipyretic, it does not have any anti-inflammatory activity.² APAP is available as a single-entity product, but is commonly found in cough, cold, and allergy combination products and sleep aids. Since APAP can be found in more than 600 OTC and prescription products, patients should be advised to always check medication labels if taking multiple medications to avoid potential therapeutic duplication and toxicities.^2,5

Patients should be reminded not to exceed the recommended daily dosages; at doses greater than 4 grams per day, APAP is potentially hepatoxic.² In 2012, the maximum daily dose for adult formulations of regular strength APAP was decreased from 3900 mg to 3250 mg.²

APAP is generally the preferred analgesic for the elderly patient population, when appropriate, because they are at greater risk for the adverse reactions related to salicylates and NSAIDs.²

While APAP is often considered to be the analgesic of choice for individuals also taking warfarin, it can elevate an individual’s international normalized ratio; therefore patients should be advised to avoid routine use of APAP when possible and always consult their physician before using OTC analgesics.^2,9 The concurrent use of APAP and alcohol can increase the risk of hepatoxicity, and individuals who consume 3 or more alcoholic drinks per day should avoid APAP.²

NSAIDs

Available nonprescription NSAIDs include the proprionic acid derivatives ibuprofen and naproxen sodium. NSAIDs have the potential to interact with a variety of prescription medications. Examples of clinically significant drug interactions associated with NSAIDs include bisphosphonates, digoxin, beta blockers, ACE inhibitors, diuretics, anticoagulants, and methotrexate.^2,10 Patients with a history of impaired renal function, congestive heart failure, or medical conditions that compromise renal hemodynamics should not self-medicate with NSAIDs.^2,10

The most common adverse effects associated with the use of NSAIDs include dyspepsia, nausea, heartburn, and epigastric pain.² GI bleeding is the major risk factor associated with NSAIDs and results from clinical studies report that older adults are at greater risk of GI bleeding when compared with younger individuals.^2,9 These agents produce less GI upset and bleeding when compared with aspirin.² Patients should be instructed to take NSAIDs with food, milk, or antacids if they experience GI upset.

Currently, the American Heart Association (AHA) recommends that patients with or at high risk for CVD (ie, hyperlipdemia, diabetes, hypertension, and other macrovascular disease) avoid NSAIDs.^2,10 In a 2007 issue of Circulation, naproxen was identified as the preferred drug and appeared to be safer than ibuprofen.^2,10 The AHA also recommends that patients use the lowest possible dose for the shortest duration of time.^2,11 The FDA recommends that patients use NSAIDs for no more than 10 days unless otherwise directed by a physician.²

Salicylates

Available nonprescription salicylates include aspirin (ASA) and magnesium salicylate. The use of ASA is associated with several clinically significant drug—drug interactions including valproic acid, beta blockers, ACE inhibitors, diuretics, anticoagulants, methotrexate, and sulfonylureas.² The maximum analgesic dose for self-medication with ASA is 4 gm/day; however, dosages of 4 gm to 6 gm/day may be needed to produce anti-inflammatory effects.² ASA and other salicylates should not be administered to patients 15 years and younger who are recovering from the chicken pox or influenza.² Patients with gout or diabetes should avoid the use of ASA unless otherwise directed by their physician. Patients with renal impairment should consult their primary health care provider prior to using ASA or other salicylates.² Individuals with risk factors for upper GI bleeding should avoid the use of ASA, as well as individuals on anticoagulants and those with hepatic and renal disorders or heart failure.²

Topical Analgesics

Topical analgesics are commonly used for minor musculoskeletal injuries (strains and sprains) and include camphor, menthol, methyl salicylate, methyl nicotinate, trolamine salicylate, and capsacin.¹¹ These products may have local analgesic, anesthetic, antipruritic, and/or counterirritant effects.¹¹ When used properly, they are considered to be safe and effective and are intended for external use only and for a short duration. Patients on anticoagulation therapy should be advised to not use topical products that contain salicylates since concomitant use has been associated with prolonged prothrombin time.¹¹

These products should be used as directed and only be applied to intact skin. Areas treated with counterirritants should never be covered with tight bandages or occlusive dressing.¹¹ Products should be discontinued if the patient experiences excessive redness or blistering of the skin. Patients should also be advised not to use heating devices in conjunction with topical counterirritants.¹¹

An excellent patient resource for the safe use of OTC analgesics is The Best Way to Take Your OTC Pain Reliever? Seriously, which can be found on the FDA website at http://www.fda.gov/downloads/drugs/emergencypreparedness/bioterrorismanddrugpreparedness/ucm133422.pdf.

References

1. Henderson M. Self care and nonprescription pharmacotherapy. In: Krinsky D, Berardi R, Ferreri S, et al, eds. Handbook of Nonprescription Drugs. 17th ed. Washington, DC: American Pharmacists Association; 2012.

2. Remington T. Headache. In: Krinsky D, Berardi R, Ferreri S, et al, eds. Handbook of Nonprescription Drugs. 17th ed. Washington, DC: American Pharmacists Association; 2012.

3. FDA requires additional labeling for over-the-counter pain relievers and fever reducers to help consumers use products safely [press release]. FDA website. www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/2009/ucm149573.htm.

4. Ostapowicz G, Fontana RJ, Schiodt RV, et al; for the US Acute Liver Failure Study Group. Results of a prospective study of acute liver failure at 17 tertiary care centers in the United States. Ann Intern Med. 2002:137:947-954.

5. A guide to safe use of pain medicine. FDA website. www.fda.gov/downloads/ForConsumers/ConsumerUpdates/ucm095742.pdf.

6. Glaser J. Educating the older adult in over the counter medication use. Medscape website. www.medscape.com/viewarticle/705665_2.

7. Cham E, Hall L, Ernst AA, Weiss SJ. Awareness and use of over-the-counter pain medications: a survey of emergency department patients. South Med J. 2002;95(5):529-535.

8. Over the counter medications: use in general and special populations, therapeutic errors, misuse, storage and disposal. American College of Preventative Medicine website. http://c.ymcdn.com/sites/www.acpm.org/resource/resmgr/timetools-files/otcmedsclinicalreference.pdf.

9. Frederick AM, Pan DE, Johnson GE. OTC analgesics and drug interactions: clinical implications. Osteopath Med Prim Care. 2008;2:2.

10. Antman EM, Bennett JS, Daugherty A, et al. Use of nonsteroidal anti-inflammatory drugs: an update for clinicians. Circulation. 2007;115(12):1634-1642.

11. Olenak J. Musculoskeletal injuries and disorders. In: Krinsky D, Berardi R, Ferreri S, et al, eds. Handbook of Nonprescription Drugs. 17th ed. Washington, DC: American Pharmacists Association; 2012.

About the Author

Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.