The American Thoracic Society (ATS) and Infectious Disease Society of America (IDSA) recommends a standard treatment for pulmonary NTM disease of three or four medications. These include clarithromycin or azithromycin, rifampin or rifabutin and ethambutol, and streptomycin or amikacin. Read more about these medications below or click here for a PDF chart of medications and side effects.
Certain combinations of antibiotics work better together because they attack the mycobacteria in more than one way. Drug combinations are often prescribed to effectively treat a specific strain of NTM. For this reason, it is very important that your sputum samples be sent to a qualified, specialized mycobacteriology lab for precise identification of the species and sensitivity testing.
Occasionally the standard therapy will fail, or another combination of drugs will be recommended depending on the strain of NTM. In that case, medications may be added or changed.
Amikacin is from a class of medications called aminoglycosides. It cannot be taken orally; it is administered by injection, intravenously, or by inhalation. Common side effects from taking amikacin include sounds in the ear (tinnitus), hearing loss, poor balance, and kidney damage/failure. Rarely a rash might occur. Injected Amikacin tends to be more toxic and is more expensive.
Periodically there are shortages of this medication. Click here for the latest information on shortages and ordering instructions for pharmacists.
Rifampin is taken orally in pill form. Many patients experience slight changes in liver function tests while taking rifampin. Other side effects such as gastrointestinal upset, fever, flushing, and itching without rash may also occur. Blood abnormalities such as a decrease in the blood cells that aid in clotting (platelets), known as thrombocytopenia, may occur. Rarely, patients may develop a worsening of kidney function.
Rifampin pills are orange in color, and because this color is absorbed in the body, body fluids may temporarily appear orange or red for several hours after taking the medicine. People taking rifampin should not wear soft contact lenses, as the lenses will permanently absorb the orange discoloration (disposable contact lenses may be a suitable alternative). Extremely high doses of rifampin may cause a condition known as “Redman syndrome.” Symptoms generally begin within 5 or 10 minutes of receiving the drug, and include itching and flushing of the face, neck and torso, and less frequently, swelling of the lips, face, or eyes, or a drop in blood pressure.
Rifampin and Rifabutin belong to a class of drugs called “Rifamycin,”.
Ethambutol is a pill administered according to the patient’s weight in kilograms. The most significant side effect of ethambutol is associated with nerves; this includes inflammation of the optic nerve (optic neuritis). Patients often complain of blurry vision and often have problems with red-green color discrimination, or with seeing colors in rich hues. This tends to occur on high daily doses of the medicine. (Allergic reactions may occur on any drug dosage of the medicine.)
Optic neuritis usually improves slowly over months. Patients taking ethambutol should have baseline eye tests performed before starting the medication and should contact their physician promptly if symptoms of blurry vision or other eye problems occur. Less frequently, patients experience gastrointestinal upset, skin rash or irritations, fever, and muscle aches.
Azithromycin is an alternative macrolide drug to clarithromycin taken in pill form. Some patients who can’t tolerate clarithromycin may be able to take azithromycin. However, this drug can cause abnormal changes in the electrical activity of the heart that may lead to a dangerous irregular heart rhythm. Patients at particular risk for developing this condition include those with known risk factors such as existing QT interval prolongation (Long QT Syndrome), low blood levels of potassium or magnesium, a slower than normal heart rate, or use of certain drugs used to treat abnormal heart rhythms, or arrhythmias. Patients should be evaluated for these conditions prior to starting azithromycin and speak with their doctor about having regular EKGs if taking it. Other side effects may include diarrhea and gastrointestinal upset, hearing loss and tinnitus. These are generally reversible when the drug is stopped or with lower drug doses.
Clarithromycin is a macrolide drug that is well absorbed in pill form. The most common side effects are metallic or bitter taste, loss of appetite, nausea, vomiting, and diarrhea. Abnormalities in liver enzymes may also occur, usually in patients on higher dosages.
Clarithromycin should never be taken alone or combined only with a quinolone drug (includes ciprofloxacin and levofloxacin) for the treatment of MAC due to the risk of developing drug resistance.
Streptomycin is given by injection. The main side effects are problems with balance and auditory (ears) toxicity. Patients taking streptomycin should be aware of decreased hearing, tinnitus, and problems with balance, numbness or tingling, fever and headache. Kidney damage may also occur, as well as changes in blood counts, so these should be routinely monitored while on this drug.
Streptomycin is not readily available in all pharmacies. It is generally given to patients with severe disease, or who have failed the standard drug regimen.
Clofazimine (Lamprene) has been used in the past primarily to treat leprosy (Mycobacterium leprae). However, it is sometimes used to treat patients with MAC, especially with drug resistant strains of MAC or when standard therapy has failed.
Gastrointestinal upset including loss of appetite (anorexia), diarrhea, and abdominal pain are the most common side effect. Dry mouth and skin may occur, and in rare cases, patients may experience skin discoloration.
Clofazimine is available either through the Novartis Expanded Access Program (new prescriptions) or by special application to the FDA to get approval for its use (existing prescriptions). For more information on applying to the FDA for Clofazimine use, click here.
Quinolone antibiotics such as ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin, are sometimes used in the treatment of MAC, even though their effectiveness is less than optimal. Patients should not take a quinolone alone or with just azithromycin or clarithromycin. Side effects including dizziness, diarrhea, nausea, and significant weight loss are not uncommon. Their efficacy is not widely known in the treatment of MAC.
In patients who take rifampin initially and do not see an improvement in the infection, rifabutin is considered as a replacement for rifampin.
Antibiotic treatment can be associated with increased incidences of gastrointestinal upset or yeast infection. For some helpful hints on how to manage these and other side effects, read Managing Side Effects.