The TV ad, which was also shown on ITV's video on demand service, was created by Abbott Mead Vickers BBDO and showed a woman and a man sitting near each other at a bar.
A breaking news story then played on the bar's TV and a reporter said: "I can now officially confirm that a huge asteroid is on a collision course with Earth and will destroy all life."
The woman and the man look at each other for a moment before kissing and falling to the floor.
The ad then cut to the bar's kitchen where the barman and the reporter from the TV were shown to be broadcasting from a mock-up news studio.
Of the 49 complaints, 34 viewers thought the ad was harmful because it condoned deception as a means of obtaining sex, condoned rape or sexual assault and promoted casual sex.
Thirty-six viewers also challenged whether the ad was offensive, because they believed the ad was sexist, demeaned women and portrayed men as sexual predators.
Pepsi said the theme of men attempting to gain the attention of attractive women was universal in storytelling and frequently featured in broadcast content, including advertising.
Eight viewers challenged whether the ad was suitable to be broadcast at times when children might be watching.
However, Clearcast said the ad, which first aired in February, was given an ex-kids restriction, meaning it could not be shown in or around programmes aimed specifically at young children.
Two complainants challenged whether the ad was offensive, because they believed the ad was sexist and portrayed women as sex objects.
There were also two complaints challenging whether the ad was harmful, because they believed it implied that it was acceptable to use deception to initiate a sexual encounter.
Pepsi said they believed that the majority of viewers would take the ad in the light-hearted manner and did not believe that it contained concepts which offended against generally accepted moral, social or cultural standards or offended public feeling.
The ASA investigated all 49 complaints but ruled that no further action should be taken, arguing that the ad presented a "fantastical" scenario and was unlikely to cause widespread offence.