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Scott Kappes
Scott Kappes
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Levaquin Gets New “Black Box” Warning for Worsening of Myasthenia Gravis


The FDA recently announced that the prescription antibiotic Levaquin, and other fluoroquinolone antibiotics will now carry a new boxed warning for the exacerbation of myasthenia gravis. The infamous black box warning is the strongest cautionary warning the FDA can issue for a medication. Fluoroquinolones also carry a black box warning for the potential to cause painful tendon ruptures, tendonitis and other tendon injuries.

Myasthenia gravis is a neuromuscular disorder that causes the weakness of voluntary muscles. This weakness occurs because the nerve that activates a particular muscle does a poor job of stimulating the muscle. The nerves do not perform properly because immune cells that normally attack foreign invaders actually attack the body’s healthy cells.

This is what is what is known as an autoimmune response. As with other autoimmune disorders antibodies block neurotransmitters from receiving messages from nerves.

According to the new safety information provided on the FDA’s website physicians should avoid prescribing Levaquin and other fluoroquinolones to patients with a known history of myasthenia gravis.


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  1. Edith Greentree says:
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    I have been taking Levaquin for 7 to 10 day periods off and on for over 2 years. I have not noticed a worsening of my MG during any of these periods. I will ask my Neurologist about it the next time I have an appointment.

  2. anitamahas says:
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    please continue the good work.