A report published in the U.S. Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report said subsequently, other state TB programs, including California, Indiana, Maryland, New York, Virginia and Wisconsin, reported difficulty obtaining the tablets as well.
Other programs, such as San Diego's, experienced difficulties obtaining at least one of the commercially available anti-TB preparations containing the combination of rifampin and isoniazid.
"These are the two most important drugs used to treat TB disease and latent TB infection. For TB disease, patients currently take up to 11 tablets a day as part of a four-drug regimen -- 2 rifampin 300 mg, one anti-tuberculosis medication isoniazid 300 mg, four pyrazinamide 500 mg and four ethambutol 400 mg tablets," the report said.
"Fixed-dose combinations decrease tablet numbers and minimize inadvertent omission of one or more required medications, which can lead to drug-resistant TB. A shortage of 300 mg anti-tuberculosis medication isoniazid tablets required an increase in the daily tablet intake for TB disease from 11 to 13 tablets and for latent TB infection from one to three tablets."
In the United States, the latent TB infection treatment completion rate is about 60 percent for nine months of daily isoniazid dosages; increasing the number of required tablets might decrease compliance. Because of the shortage of isoniazid 300 mg tablets, some programs have restricted latent TB infection treatment to contacts of people with tuberculosis.