The so called Food and Drug Administration Safety and Innovation Act (FDASIA) requires the FDA to publish reports on the inspection of registered establishments every year starting with the fiscal year 2013. The first Annual Report is available now.
In total, the FDA counts 34,466 drug and device establishments which need to be inspected. The majority of the manufacturing sites are for medical devices manufacturing (21,853). The total number of drug establishments is 12,613: most of them are located in the US (9,120 domestic sites compared to 3,493 outside the US). The drug establishments count 4,360 sites for Finished Dosage Forms and 1,248 for APIs. The remaining 7,005 sites are listed as "Others" and include sites for medical gases, medicated feed as well as biologic drug products.
When it comes to the number of inspections performed, it is obvious that FDA can't be in the position to inspect each facility every three years. However, the FDA has invested significantly in its inspection capacity. In 2014, 5,996 GMP Inspections were performed, around 80% of them in the US and 20% outside the US. This is quite surprising as this means that the FDA didn't perform the same percentage of inspections in foreign countries although the number of foreign manufacturing sites is about 37% of the total number of manufacturing sites. Now it is necessary to say that the report data only concern GMP compliance inspections. For example pre-approval inspections are not covered in the report. Based on the data available in the report, one can say that the average inspection period is every 5 to 6 years. However, the FDA uses a risk based approach for its inspections. Some facilities might not be as critical as others. For example production sites with aseptic processing are more likely to be inspected more frequently than facilities for solid dosage forms.