From the Guidelines
Azithromycin should be avoided in patients with Myasthenia Gravis due to its potential to worsen the condition. This recommendation is based on the understanding that macrolides, the class of antibiotics to which azithromycin belongs, can exacerbate myasthenia gravis by interfering with neuromuscular transmission 1. The American Society of Clinical Oncology clinical practice guideline from 2018 advises against the use of macrolides, among other medications, in patients with myasthenia gravis because they can worsen the condition 1.
Key Considerations
- Azithromycin's mechanism of impairing neuromuscular transmission can lead to increased muscle weakness in patients with myasthenia gravis.
- The use of azithromycin may trigger a myasthenic crisis, a life-threatening condition requiring immediate medical intervention.
- Alternative antibiotics that do not affect neuromuscular transmission should be considered first when treating infections in patients with myasthenia gravis.
Clinical Approach
If antibiotic treatment is necessary, the following steps should be taken:
- Choose alternative antibiotics that are safer for patients with myasthenia gravis.
- If azithromycin is deemed necessary, it should be used under close medical supervision, ideally in a hospital setting where support for potential respiratory failure is available.
- Patients should be closely monitored for signs of worsening myasthenia gravis, such as increased muscle weakness, breathing difficulties, swallowing problems, or slurred speech, and the medication should be discontinued at the first sign of these symptoms 1.
From the FDA Drug Label
Worsening of myasthenia gravis (a problem that causes muscle weakness). Certain antibiotics like azithromycin tablets may cause worsening of myasthenia gravis symptoms, including muscle weakness and breathing problems. Call your healthcare provider right away if you have any worsening muscle weakness or breathing problems. Azithromycin may exacerbate muscle weakness in persons with myasthenia gravis. ( 5.7)
Azithromycin is not safe to use in patients with Myasthenia Gravis due to the potential for worsening muscle weakness and breathing problems. Patients with Myasthenia Gravis should be closely monitored by their healthcare provider if azithromycin is prescribed. 2 2
From the Research
Azithromycin and Myasthenia Gravis
- Azithromycin, a macrolide antibiotic, has been reported to exacerbate myasthenia gravis in a case study published in 1996 3.
- The study describes a 25-year-old female patient with severe aggravation of myasthenia gravis due to azithromycin, which was prescribed for an influenza syndrome.
- The patient developed weakness of the legs and respiratory distress due to respiratory muscle failure one hour after taking 500 mg of azithromycin.
Safety of Azithromycin in Patients with Myasthenia Gravis
- The 1996 case study suggests that azithromycin can exacerbate myasthenia gravis and should be used with caution in patients with this condition 3.
- While there are no other studies directly linking azithromycin to myasthenia gravis exacerbation, other antibiotics such as fluoroquinolones have been reported to worsen myasthenia gravis symptoms 4, 5, 6.
- A 2020 case series reported exacerbation of myasthenia gravis after amoxicillin therapy, highlighting the need for caution when using antibiotics in patients with myasthenia gravis 7.
Key Findings
- Azithromycin may exacerbate myasthenia gravis, as reported in a 1996 case study 3.
- Fluoroquinolones have been shown to block neuromuscular transmission and worsen myasthenia gravis symptoms 4, 5, 6.
- Antibiotics such as amoxicillin may also exacerbate myasthenia gravis, as reported in a 2020 case series 7.