The Russian tested positive to the substance, added to the World Anti-Doping Agency (WADA) prohibited list at the start of the year, at the Australian Open and faces a ban.
Reports had suggested Sharapova, a five-time grand-slam champion, ignored multiple warnings about the drug's addition.
In a Facebook post on Friday, the 28-year-old labelled such reports exaggerated.
"A report said that I had been warned five times about the upcoming ban on the medicine I was taking. That is not true and it never happened," Sharapova wrote.
"That's a distortion of the actual 'communications' which were provided or simply posted onto a webpage.
"I make no excuses for not knowing about the ban. I already told you about the December 22, 2015 email I received.
"Its subject line was 'Main Changes to the Tennis Anti-Doping Programme for 2016.' I should have paid more attention to it.
"But the other 'communications'? They were buried in newsletters, websites, or handouts."
Sharapova pointed to a newsletter received via email, covering numerous topics including the likes of travel, upcoming tournaments, rankings, statistics and anti-doping information.
She added: "In other words, in order to be aware of this 'warning', you had to open an email with a subject line having nothing to do with anti-doping, click on a webpage, enter a password, enter a username, hunt, click, hunt, click, hunt, click, scroll and read.
"I guess some in the media can call that a warning. I think most people would call it too hard to find.
"There was also a 'wallet card' distributed at various tournaments at the beginning of 2016, after the ban went into effect.
"This document had thousands of words on it, many of them technical, in small print. Should I have studied it? Yes. But if you saw this document [attached], you would know what I mean.
"Again, no excuses, but it's wrong to say I was warned five times."
Sharapova also said she only used the medicine as recommended by her doctor after a story claimed it was normally taken for 4-6 weeks.
The Russian had been taking meldonium for 10 years, but insisted it was in low doses and as recommended.