The drug - mycophenolate mofetil - is the first to be approved since the manufacturing facility on W. Grand Avenue, Decatur passed a US Food and Drug Administration (FDA) re-inspection in December.
Last summer Akorn was issued with a Form 483 after agency inspectors identified a number of problems after an FDA audit.
Akorn welcomed the approaval and predicted that abbreviated new drug applications (ANDAs) for other injectables made at the site would be approved.
CEO Raj Rai told investors the decision “implies that we should now expect to receive approvals for other filings" delayed due to the site's compliance status.
Akorn has 90 ANDAs filed with the FDA, however, not all of these are produced at the W. Grand Avenue facility.
The US FDA also approved a New Drug Application (NDA) for an anaesthetic called ephedrine sulfate that is made at the Decatur facility.
This ephedrine approval was reflected in Akron's guidance for 2017.
The firm said it will generate revenue of $1.01bn and $1.06bn with new products, including ephedrine, expected to contribute $30m to $60m.
It also predicted it woultwo ephedrine competitors for the remainder of 2017 and forecast that it will hold 30%-35% of the market.