Speirs, 39, has been embroiled in controversy since he quit the leadership on August 8, declaring that he had "just had a gutful" of leadership speculation and did not have the energy to keep fighting.
Speirs originally faced two charges of supplying a controlled substance from August 2-3 and on August 9, but one charge was dropped and the other has been varied.
He is now charged with supplying or administering a drug (not cannabis) to another person between August 1 and August 10 at Kingston Park.
In court, his lawyer Dominic Agresta asked that his client's bail be varied to allow him to travel overseas.
Prosecutors agreed that Speirs' passport be returned to him but he must lodge his itinerary with police and provide a guarantor for $15,000, with a similar cash surety.
No details of his destination were given in court, but he was ordered to report to police on his return from overseas and hand back his passport.
David Speirs said it was a very difficult time for him, friends and family. (Matt Turner/AAP PHOTOS)
Outside court, Speirs said he would not talk specifically about what happened in court.
"That's not appropriate," he said.
"However, I acknowledge this has been a very difficult time for me personally, a very difficult time for friends and for family members."
He thanked the "many hundreds of people in South Australia who have been so supportive of me and have reached out to see if I'm OK".
"It has actually sustained me during this time," he said.
"I didn't need to leave parliament. There was no compulsion to do so ... I couldn't execute my responsibilities as a member of parliament and also deal with my mental health and wellbeing through this process."
Speirs resigned from parliament on October 15, clearing the way for a by-election in his southern Adelaide seat on Saturday.
David Speirs said Liberal candidate Amanda Wilson was above the misogyny, bullying and nastiness. (Roy Vandervegt/AAP PHOTOS)
He said that serving the electors of Black was "the greatest privilege of my life ... and I will miss it".
He said the Liberal candidate, Amanda Wilson, had been subjected to the "brutal Labor Party machine in the same way that I have over the years".
"The misogynistic campaign, the bullying, the nastiness, but Amanda is above that and I wish her all the very best and I've cast my vote for Amanda," he said.
On September 9, News Corp published a video purportedly showing Speirs snorting a powder.
He declared the footage to be a "deepfake" and vowed to clear his name.
David Speirs previously vowed to clear his name. (Matt Turner/AAP PHOTOS)
Two days later, he took medical leave, saying the past few days had been "exceptionally distressing" and that he was left "feeling exceptionally vulnerable and at risk".
On October 5, Speirs released a video statement saying he did not believe he could "adequately and effectively serve my local community while also dealing with this matter, protecting my mental health and supporting my family and friends".
"Since allegations of illicit substance use in my home became public, my home has been raided by armed police, I was arrested and I was questioned," he said.
His case returns to court on March 4.
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