Both are a group of rare hereditary disorders that cause episodes of muscle weakness or paralysis.
The drug is the first to be approved by the FDA to treat primary periodic paralysis, which is estimated to affect around 5,000 people in the US.
The company noted that Keveyis will be available for patients during the third quarter of this year.
Taro CEO Kal Sundaram said: "The approval of Keveyis demonstrates the importance of industry, scientific researchers, patient advocates and the FDA working together to identify and bring to market a treatment for primary periodic paralysis.
"Taro is proud of its commitment to this community, which has been waiting for a new, effective treatment option for many years. We thank the FDA for their continued partnership in making this important day a reality."
Under the Keys2Care program created by the company, a suite of patient support services will be provided to ensure people diagnosed with periodic paralysis can get treatment with Keveyis as soon as possible.
In order to provide access and support to patients who are prescribed Keveyis and their caregivers, the company is working with Diplomat Pharmacy.