Queen Naija Bulls did an official lyrics and meaning interview for the song "Medicine" with Genius in January 2018. A month after the song's release, it had 5 million views. Queen documented on her YouTube channel a few meetings with record labels that she attended with her team/management. By March 2018, Queen's initial song post of "Medicine" had more than 10 million views. An official music video was released later that month. The video acquired 4.5 million views on the day of its release, and has over 146 million views as of December 2019. In July 2018, Queen Naija created a new collaborative YouTube channel, "Royal Family", alongside her boyfriend ClarenceNYC TV. Their videos include challenges, vlogs, story times and family content. The channel has 2.64 million subscribers as of June 2020.
On April 25, 2018, Queen Naija signed to Capitol Records. On June 28, 2018, she released her second single, "Karma". She had written and recorded the song in January 2018. In an interview with Genius, she described this song as being a more personal story: "I just was trying to get a more personal because “Medicine” was personal. I just wanted to tell people how I really, really, really felt, like about not being confident about myself, and the reason why. I wanted people to know all the good that I was doing too. Like, how I stuck by his side, and all that stuff. How I was a good woman, and how I felt." On its release day, the song reached #1 overall on the iTunes charts. "Karma" closed the week as the thirteenth-best seller in the United States, thus taking #13 on the Billboard Digital Songs sales chart. In July 2018, "Karma" debuted at #63 on the Billboard Hot 100. Five months after its release, the video has over 101 million views as of December 2019.
Queen Naija released her self-titled extended play on July 27, 2018. It consists of five songs: "Medicine", "Karma", "Mama's Hand", "Butterflies", and "Bad Boy". The project includes production from No I.D., El Jefe, Rob Grimaldi, 30 HERTZ BEATS, and ClickNPress. Queen Naija has described the EP as an emotional journey in which each song describes either an experience or emotion she has gone through. The songs reference topics including heartbreak and betrayal, motherhood, and finding new love again. "Medicine" deals with her heartbreak and emotions toward her ex-partner, and "Karma" explains overcoming the heartbreak while sending a message that she will be fine. "Mama's Hand" is dedicated to her son; she promises to give him everything and encourages him to have optimistic thoughts about the future. "Butterflies" reveals that she is beginning to fall in love again with someone new. "Bad Boy" describes her connection with a new lover, and how her goodness may cause him to change for the better. In August 2018, the EP debuted at #26 on the Billboard 200 and reached #1 on the Apple Music R&B charts. Naija released the single Lie to Me featuring Lil Durk on October 2nd.
