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Magnet therapy involves the use of magnets placed on or near the body. It is based on the premise that magnetism may influence pain transmission. Two types of therapeutic magnets are used: unipolar and bipolar. Unipolar magnet therapy uses several individual magnets aligned with the same magnetic pole toward the skin, usually the biomagnetic north pole or negative pole facing the skin. Bipolar magnet therapy uses a sheet of magnetic material with an alternating spatial pattern of north and south poles so that both poles face the skin.
Scientific study of magnet therapy is still in its infancy. In one study, magnets were compared to placebo in a single 45-minute application to treat muscle pain in 50 patients with postpolio syndrome; the magnets were effective for pain (Valbona, 1997). Another study showed a statistically significant reduction in neuropathic pain in patients with diabetic polyneuropathy using magnetic foot pads for a total of 12 weeks (Weintraub, 1998). Recently, bipolar permanent magnets were tested in a small pilot study of 20 patients with chronic low back pain. No differences were found between the real magnet and the sham magnets in terms of severity of pain, emotional components of pain, or physical response to pain (Collacott, 2000). In a study of knee pain in patients with rheumatoid arthritis, subjects in the magnet group reported a greater reduction in pain than the control group (40.4% vs. 25.9%), a greater decrease in assessment of disease activity over one week (33% vs. 2%), and feeling better or much better after one week (68% vs. 27%) (Segal, 2001). In contrast, a recent study of static magnetic fields for the treatment of fibromyalgia concluded that improvements in the magnetic therapy group did not differ significantly from changes in the control groups (Alfano, 2001). Further trials are needed to assess the effectiveness of magnet therapy. Although magnets are usually very safe, they should not be used by patients who have pacemakers, insulin pumps, or metal implants that could be dislodged by magnet use. Some clinicians warn against the use of magnets in patients who are pregnant, have a history of epilepsy, take blood-thinning medications, or have bleeding problems. Finally, patients using transdermal drug delivery systems should not place a magnet close to the patches, because it is possible that the magnet could affect the drug's absorption rate (Gescedi, 2001) (MICROMEDEX, 2002).
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