10 Things You Should Know About Voltaren Gel

Voltaren Gel (diclofenac) was the first prescription topical treatment for osteoarthritis approved by the Food and Drug Administration (FDA). Voltaren Gel, a nonsteroidal anti-inflammatory drug (NSAID) in topical form, is mostly used on knees and hands. If you're thinking about taking Voltaren Gel, here's what you need to know about the drug's safe use and effectiveness.

The systemic absorption of Voltaren Gel, which is 1 percent diclofenac sodium in a topical gel formulation, is 94 percent less than oral diclofenac. That means the risk of serious gastrointestinal and cardiovascular side effects associated with oral NSAIDs is considerably less with the topical formulation.

The FDA approval was based on several studies, including two randomized, double-blind, placebo-controlled efficacy studies and a 12-month safety study. After six weeks of treatment in an efficacy study of people with hand osteoarthritis, pain levels were reduced by 46 percent. In a 12-week study of people with knee osteoarthritis, Voltaren Gel reduced pain levels by 51 percent.

The most common adverse reactions reported in clinical trials were application site reactions in 7 percent of study participants treated with Voltaren Gel. The prescribing information for Voltaren Gel provides warnings and precautions for serious adverse reactions as well. Long-term administration of NSAIDs can result in renal (kidney) papillary necrosis and another renal injury. The elderly, people with impaired renal function, heart failure, liver dysfunction, and those taking diuretics and ACE inhibitors should be cautious when using Voltaren Gel. Hypertension can occur with NSAID treatment, making it important to monitor blood pressure. Fluid retention and edema may also occur. If an anaphylactoid reaction occurs, use should be discontinued immediately. NSAIDs can cause serious skin adverse events, too, including exfoliative dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis, which can be fatal.

In 2009, the FDA updated the label for Voltaren Gel to include information about possible hepatic (liver) effects.

It now reads, "In postmarketing reports, cases of drug-induced hepatotoxicity have been reported in the first month, and in some cases, the first two months of therapy, but can occur at any time during treatment with diclofenac. Postmarketing surveillance has reported cases of severe hepatic reactions, including liver necrosis, jaundice, fulfillment hepatitis with and without jaundice, and liver failure. Some of these reported cases resulted in fatalities or liver transplantation. Physicians should measure transaminases periodically in patients receiving long-term therapy with diclofenac, because severe hepatotoxicity may develop without a prodrome of distinguishing symptoms."

Black box warnings alert physicians and patients to the most severe possible side effects.

Voltaren Gel has two black box warnings that are common to all NSAIDs.

The first is that, as with other NSAIDs, there may be an increased risk of serious or possibly fatal cardiovascular events, heart attack, or stroke with the use of Voltaren Gel. These can happen without warning. Your risk may be higher if you've been taking NSAIDs for a long time or at high dosages. If you are at risk for cardiac events and stroke, you should not take this medication. It should not be used for pain relief before or after coronary artery bypass graft surgery (CABG).

NSAID use can cause an increased risk of serious gastrointestinal events which may include bleeding, ulcers, and perforation of the stomach and intestines. These adverse events can happen without warning and could possibly be fatal. You're more at risk if you're elderly or have a history peptic ulcer disease or gastrointestinal bleeding.

Besides the groups at increased risk listed in the black box warnings, Voltaren Gel should not be used by people with known hypersensitivity to diclofenac. It also should not be used by people who developed asthma, urticaria, or allergic reactions after taking aspirin or NSAIDs. This product can cause reversible delayed ovulation, which may be a concern if you're a woman who wants to get pregnant. If you're pregnant, you should not use Voltaren Gel after 30 weeks gestation as it may cause a fetal heart defect.

Voltaren Gel should not be used together with oral NSAIDs or aspirin because of an increased risk of adverse events. The risk of side effects increases with the increased absorption of the active ingredients in NSAIDs. Just as topical NSAID cream should not be used with oral NSAIDs, two different oral NSAIDs should not be taken together. Talk to your doctor about using low-dose aspirin.

If you're using cosmetics or sunscreen, don't use Voltaren Gel at the same time. The combinations have not been tested and, if topical agents are combined, there is the potential to change how Voltaren Gel is tolerated and absorbed. 

After learning how Voltaren Gel shouldn't be used and who shouldn't use it, you may be wondering who should use it. People who've experienced gastrointestinal side effects from oral NSAIDs are clearly the ones who will benefit most from Voltaren Gel. If you think you may be a candidate for Voltaren Gel, discuss it with your doctor to determine if it's appropriate for you. 

Never use more than the prescribed amount.

Voltaren Gel should be measured onto the reusable dosing card which is enclosed—measure to the appropriate 2-gram or 4-gram mark. For lower extremities, apply the gel (4 grams) to the affected area four times daily. Do not apply more than 16 grams daily to anyone affected joint of the lower extremities. For upper extremities, apply the gel (2 grams) to the affected area four times daily. Do not apply more than 8 grams daily to anyone affected joint of the upper extremities.

Avoid getting this medication in your eyes, mouth, open wounds, or infected areas. Unless you're applying it to your hand joints, wash your hands immediately after application. Don't shower or rinse the area treated for at least an hour and don't put clothes over it for at least 10 minutes. Two other don'ts: Avoid sunlight and artificial sunlight after application and don't heat the treated joint. 

The more treatment options there are for people with arthritis, the better, and the availability of a topical formulation of Voltaren is important for people who can't tolerate oral NSAIDs for one reason or another. Just be aware that both oral and topical NSAIDs carry the same risks, and that Voltaren shouldn't be combined with other NSAIDs.