Arthritis is the term for joint inflammation. There are several different types of arthritis but the two most common are osteoarthritis and rheumatoid arthritis. Whereas osteoarthritis is mainly due to the erosion of the joint cartilage surrounding the ends of the bones, rheumatoid arthritis primarily involves the joint lining known as the synovium. Despite the term, osteoarthritis is not marked by inflammation although it may occur occasionally. Instead it is more of a degenerative disorder of the cartilage and bone. Drug therapy for osteoarthritis mainly aims at providing symptomatic relief of the pain and the inflammation which occasionally associated with the disease. Rheumatoid arthritis is marked by varying degrees of inflammation of the joint lining as a result of autoimmune processes. It is a progressive disorder meaning that it worsens over time. The treatment of rheumatoid arthritis focuses on control of disease progression and reduction of joint inflammation in addition to relief of pain.
Types of Treatment
Medication can provide symptomatic relief (palliative) or modify the disease processes thereby slowing the progression. Drugs for symptomatic relief (pain and inflammation) include :
- Acetaminophen (paracetamol)
- Non steroidal anti inflammatory drugs (NSAIDs)
- Selective cyclooxygenase-2 (COX-2) inhibitors
- Opioid painkillers
- Other medications such as capsaicin cream and opioids
Acetaminophen (paracetamol) is very good for pain relief but it is of minimal use in reducing inflammation of joints. This makes acetaminophen a preferred initial drug in the treatment of osteoarthritis which is usually not associated with joint inflammation. Acetaminophen may be of use in rheumatoid arthritis patients in whom pain control alone is needed or in patients whom use of more toxic NSAIDs are to be avoided or reduced.
It is usually administered at a dose of 500mg every 6 hours and it may be increased up to a maximum of 4 grams in a day. It does not cause gastric irritation as compared to other NSAIDs. Liver toxicity is the major concern with its use. Doses above 4 grams are not generally recommended as it can cause damage of liver and kidney in high doses. It should be avoided in patients with liver failure and used with caution in chronic alcoholics.
NSAIDs are popular pain relief agents. Commonly used NSAIDs include diclofenac, ibuprofen, indomethacin, aceclofenac, meloxicam, nabumetone, and aspirin. NSAIDs are the most frequently used drugs for treatment of arthritic pain of osteoarthritis and rheumatoid arthritis. The NSAIDs produce greater improvement in pain than high dose acetaminophen. NSAIDs also produce significant reduction in inflammation associated with rheumatoid arthritis and osteoarthritis.
Use of NSAIDs should ideally be restricted to intermittent use or use based on requirement rather than continuous treatment.This helps in preventing development of serious adverse effects but daily treatment may be required in patients who are insufficiently responding to intermittent therapy. Osteoarthritis patients may also benefit from topical NSAID applications in the early stages. Topical preparations are free of the major side effects associated with the oral preparations and it may be preferred over oral NSAIDs in patients experiencing improvements with it.
NSAID use is frequently associated with significant side effects. The most important side effect of NSAID is upper gastrointestinal toxicity which includes :
- peptic ulcer disease
- gastrointestinal bleeding
- abdominal discomfort
Some patients may even discontinue the treatment due to severe gastrointestinal side effects. In order to reduce gastrointestinal (GI) side effects NSAIDs are generally recommended to be taken after food. Patients with high risk of GI toxicity are usually given acid reducing agents like pantoprazole (proton pump inhibitor) or misoprostol (mucosal protective prostaglandin analogue) for limiting GI toxicity. Gastrointestinal toxicity is high for aspirin, indomethacin, piroxicam, ketorolac and less for NSAIDs like nabumetone and ibuprofen. Other side effects of NSAIDs include drug rashes, edema, kidney damage and elevation of liver enzymes due to liver damage.
Arthritis Selective COX-2 Inhibitors
Selective COX-2 inhibitors are as effective as NSAIDs in relieving pain and inflammation in rheumatoid arthritis and in osteoarthritis patients with joint inflammation. Celecoxib is the most commonly used COX-2 inhibitor at present. It is administered orally at a dose of 100 to 200mg twice daily. COX-2 inhibitors are associated with lesser incidence of gastrointestinal side effects, but are associated with a significant risk of developing heart attack and stroke on prolonged use. This side effect was responsible for withdrawal of drugs like rofecoxib and valdecoxib from the markets. The risk of edema and renal injury is similar to that of other NSAIDs.
Arthritis Opioid Painkillers
Opioid analgesics are the most effective painkillers. Opioids are generally not recommended for routine use in osteoarthritis or rheumatoid arthritis due to the addiction potential and the toxicity of most opioids. Some opioids or related drugs like codeine and tramadol are occasionally used in some patients for pain relief. It may be used alone or in combination with drugs like acetaminophen. Common side effects of opioids include :
- retention of urine
- dry mouth
High doses of opioids can cause depression of respiratory system or central nervous system.
Other Arthritis Medication
Topical capsaicin cream has been found to be of use in osteoarthritis for pain relief. Topical capsaicin cream can be applied locally over the affected joint 3 to 4 times a day for pain relief. This is more beneficial in the early stages of the disease and is useful in delaying or reducing requirement of more toxic oral NSAIDs. It can cause burning sensation or irritation of the skin.
Hyaluronic Acid Injections
Injections of hyaluronic acid directly into the joint cavity may be useful in some patients with osteoarthritis of knee or hip. It is a thick fluid that can lubricate the joint like the normal joint (synovial) fluid and provide relief from pain due to friction between the bones. Its effectiveness is not fully established even though it has been in use for several years. The side effects are usually mild and limited to discomfort and swelling at the injection site.
Glucosamine and Chondroitin
Oral supplementation of glucosamine and chondroitin can benefit some patients with osteoarthritis. Glucosamine and chondritin sulfate are components of the normal cartilage present in the body. Supplementation of these agents can stimulate growth of the cartilage in the joints providing better cushioning effect between the bones. This may reduce the friction between the bones and provide relief from pain. The usefulness of these agents is not well established. The adverse effects of glucosamine/chondritin treatment are mostly the gastrointestinal problems (like abdominal bloating, heartburn, diarrhoea). It is also generally avoided in diabetes patients as it can cause increase in the blood sugar levels.
Corticosteroids are highly effective in reducing pain and inflammation of joints associated with arthritis. The effect on disease progression is limited compared to the disease modifying drugs. Short-term control of symptoms in patients with severe pain and inflammation may be rapidly obtained with local injection of steroids directly into the affected joints. Corticosteroids like triamcinolone may be given as injections to the joint cavity in patients with osteoarthritis affecting knee or hip joint.
Systemic corticosteroid therapy can provide effective symptomatic relief in patients with rheumatoid arthritis. Prednisolone is the most common steroid used orally. It is administered in the dose of 60 mg orally for acute control of symptoms, and in the dose of 10 mg for maintenance therapy of the disease. A low-dose therapy with less than 7.5 mg/day may be useful as an additive therapy to the DMARD therapy aimed at delaying long-term disease progression. Use of corticosteroid is often restricted to control of acute or severe symptoms due to the side effects associated with corticosteroids use such as :
- glucose intolerance
- peptic ulcers
- thinning of skin
- ocular (eye) complications
- hypertension (high blood pressure)
- muscle weakness