Hi--I'll be glad to give you some ahdvice. I am a board-certified internist with more than 30 years experience in many specialties.
Pennsaid is the trade name for a medication whose generic name is XXXXX XXXXX XXXXXXXX is a topical solution that is easier to apply to a specific area. Diclofenac has been used orally and in patches.
Pennsaid can be used anywhere on the body--back, knees, hands--except near the eyes and where it would be swallowed.
The reason the information is about the knees is a factor of the Federal Drug Administration's rules requiring that the manufacturer of a new means of using an old medicine establish that it works. For cost effectiveness, the manufacturer of Pennsaid probably just went for the knee as it is a joint commonly found to have arthritis--that helped them do studies that showed effectiveness. More joints would have confused things.
If you use it on your hands, you would have to avoid putting your hands near your face to avoid getting the medication into your eyes or mouth (though in pill form as Voltaren, diclofenac is taken orally. But the carrier liquid for the active medicine might not be edible.) After an hour or so, washing your hands would remove the remaining medication but it would have already gone under the skin to treat the arthritis in the joints.
The reason to use topical like Pennsaid is that it goes specifically to the area with problems.
Oral diclofenac can cause stomach irritation and bleeding, so it's safer to use it topically if there is no irritation with use.
Hope this helps. Please reply with any comments or questions.
Thank you .... I will go ahead and start with this med to my aching fingers!!! G