Is Doryx contraindicated in Myasthenia gravis?

Yes, Doryx (doxycycline) is contraindicated in patients with myasthenia gravis. Doxycycline can worsen the symptoms of myasthenia gravis by interfering with the transmission of nerve impulses at the neuromuscular junction. This can lead to increased muscle weakness and fatigue, and may even be life-threatening. Therefore, doxycycline should not be used in patients with myasthenia gravis unless the potential benefits outweigh the risks and there are no other suitable alternatives.