A Pharmacist's Guide to OTC Therapy: Osteoarthritis

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

Arthralgia, commonly referred to as jointpain, can be attributed to various causes,including many types of injuries and medicalconditions. Two of the most commoncauses of arthralgia are osteoarthritisand rheumatoid arthritis.¹ Althoughmedical conditions such as rheumatoidarthritis, osteoarthritis, gouty arthritis,lupus, bursitis, tendonitis, and osteomyelitismay cause arthritic pain, accordingto the Handbook of NonprescriptionDrugs, only the pain associated withosteoarthritis is approved for self-treatmentafter an initial medical diagnosis isestablished.^1,2

Other possible causes of joint paininclude excess weight, increasing age,genetic defects in joint cartilage, sedentarylifestyle, and stress on the joint fromcertain sports activities or occupations.¹

Statistics from the Arthritis Foundationreport that an estimated 27 million individualsin the United States have somedegree of osteoarthritis.³ Whereas osteoarthritiscan occur in any joint, thecondition most often affects the weightbearingjoints of the hips, knees, andlower back. It also can affect the neck,small finger joints, the base of the thumb,and the big toe.³

The goals of treating osteoarthritisinclude relief of pain, enhancing mobilityof the joints, and improving the patient'squality of life by minimizing the pain associatedwith this condition. The treatmentselected depends on the severity ofthe osteoarthritis and may include the useof pharmacologic agents, physical therapy,rest, heat and cold therapy, weightloss, and the use of devices to take strainoff joints, such as canes and splints, andsurgery, if needed. OTC analgesics suchas nonsteroidal anti-inflammatory drugs(NSAIDs) and acetaminophen are commonlyused in the treatment of osteoarthritis.Due to its reduced adverse effectprofile when compared with NSAIDs,acetaminophen is the drug of choice fortreating osteoarthritis when inflammationis not a chief concern.² NSAIDs arepreferred when inflammationis present.Patients should be screened for potentialcontraindications and drug interactions,however, prior to using any of these OTCanalgesics.

In addition to the use of systemicagents, a variety of topical products areavailable for treating joint pain. They canbe used in conjunction with systemicagents or as the sole therapy of choice.These products may contain one or moreof the following ingredients: methyl salicylate,camphor, menthol, methyl nicotinate,capsaicin, or trolamine salicylate,and are available as gels, ointments,creams, lotions, and patches. Patientsshould be advised to only apply topicalproducts to skin that is intact and to notcover areas treated with counterirritantswith tight bandages or occlusive dressing.2 Patients also should be advisednot to use heating devices with topicalcounterirritants.² Also available for treatingjoint pain are topical heat therapypatches available in various sizes thatprovide 8 to 12 hours of continual heattherapy.

In addition to systemic and topicalanalgesics, various dietary supplements,such as glucosamine, chondroitin sulfate,methylsulfonylmethane (MSM),and S-adenosylmethionine (SAM-e) havebeen used for the treatment of jointpain. These supplements are availableas either single-entity or combinationproducts. Studies have shown that glucosaminesulfate not only reduces thepain associated with osteoarthritis, butalso may slow down the progression ofthe disease.³

Glucosamine is an endogenous mucopolysaccharideused in the synthesis ofcartilage.^4,5 The most common adverse effects of glucosamineinclude mild gastrointestinal (GI) upset, nausea, heartburn,and diarrhea, which can be alleviated if taken in divided doseswith meals. Glucosamine should not be used if an individual isallergic to shellfish. Patients with diabetes should be aware ofthe possibility of hyperglycemia when using glucosamine anddiscuss the use of this product with their physician prior touse.⁵ The most common adverse effects of chondroitin includemild GI upset and nausea.⁵

MSM has been added to many of the glucosamine/chondroitinsupplement products. Although its exact mechanism ofaction with regard to osteoarthritis is unclear, MSM has a crucialrole in maintaining the elasticity and flexibility of the connectivetissue that make up joints.^6,7 Patients should be advised thatthese supplements will not provide pain relief as quickly asNSAIDs or acetaminophen, and their therapeutic effects maynot be evident for several weeks.⁵

Another supplement that promotes joint health is SAM-e,which is produced primarily in the liver.⁵ It is best known andmarketed as a mood stabilizer. Both liver disease and lowlevels of vitamin B₁₂ and folate may reduce SAM-e levels.⁵SAM-e should not be used in conjunction with antidepressantsand 5-HT₁ agonists because of an increased risk of serotoninsyndrome.⁵

The Role of the Pharmacist

Prior to recommending any of these OTC products, pharmacistsshould assess the appropriateness of self-therapy by evaluatingthe patient's symptoms and review the patient's currentmedical history, drug profile, and allergy history, and screen fordrug?drug interactions and possible contraindications. Patientswho are currently taking any other medications, those withpreexisting conditions, and women who are pregnant or lactatingshould always consult a physician before using any of theseproducts. Patients should always be counseled on the properuse and adverse effects of these OTC agents and should bereminded to use these products as directed.

In addition, patients with severe and continual joint painshould be encouraged to seek further evaluation and treatmentfrom their primary health care provider, when warranted, and ifthey see no signs of improvement or if pain worsens.To provide more information to your patients, please visit thefollowing Web sites:

• Suggestions from the Arthritis Foundation on ProtectingYour Joints. Arthritis Foundation Web site: www.arthritis.org/protect-your-joints.php.
• Do I Have Arthritis? National Institutes of Health's NationalInstitute of Arthritis and Musculoskeletal and Skin DiseasesWeb site: www.niams.nih.gov/Health_Info/Arthritis/tengo_arthritis.asp.

References

• Arthritis. National Institute of Arthritis and Musculoskeletal and Skin Diseases Web site. www.niams.nih.gov/Health_Info/Osteoarthritis/osteoarthritis_ff.asp. Accessed July 5, 2008.
• Wright E. Musculoskeletal Injuries and Disorders. In: Berardi RR, Kroon LA, McDermott JH, et al, eds. Handbook of Nonprescription Drugs. 15th ed. Washington, DC: American Pharmacists Association; 2006:111-129.
• Osteoarthritis. Arthritis Foundation Web site. www.arthritis.org/disease-center.php?disease_id=32. Accessed July 5, 2008.
• Questions and Answers: NIH Glucosamine/Chondroitin Arthritis Intervention Trial. NIH's National Center for Complementary and Alternative Medicine Web site. nccam.nih.gov/research/results/gait/qa.htm#b2. Accessed July 5, 2008.
• McQueen C. Nonbotanical Natural Medicines. In: Berardi RR, Kroon LA, McDermott JH, et al, eds. Handbook of Nonprescription Drugs. 15th ed. Washington, DC: American Pharmacists Association; 2006:1148-1150.
• Advanced MSM. Osteo Bi-flex Product Information Web site. www.osteobiflex.com/pages/products.aspx?PPID=4. Accessed July 5, 2008.
• Naturemade TripleFlex Product Information. Naturemade Web site. www.naturemade.com/ProductDatabase/prd_prod.asp?productid=73. Accessed July 5, 2008.