FDA plans to study generic copies of AstraZeneca’s extended-release blood pressure medication Toprol XL (metroprolol succinate), amid 3,424 adverse-incident reports made against the drugs.

Those AE reports cite “a lack of effectiveness and troublesome side effects,” reports Bloomberg, which analyzed them.

According to the news service, FDA will assess whether the copies are chemically the same as the original, as noted in a funding request made by the agency.

The generic copies in question are manufactured by Wockhardt Ltd. and Dr. Reddy’s Laboratories, both of which are based in India, and by US-based Mylan and Actavis.

The effort to evaluate metoprolol succinate broadens on a $20-million FDA testing program begun in September, Bloomberg points out, and follows criticism of the agency’s handling of generics made overseas and distributed domestically.