It was during Parveen Babi's medical curing in Banglore that a major incident occurred. She woke up in the middle lf the night crying for Amitabh Bachchan. She was hysterical and uncontrollable. Mahesh Bhatt decided to swallow his pride and have a man to man talk with Amitabh . Mahesh visited the sets of Dostana. He pleaded with Amitabh to be extra nice to Parveen as she had a serious mental condition. Amitabh listened to Mahesh's story and promised he would do as much as he could. He asked Mahesh to take care of her as she had several pending films left to complete. This angered Mahesh. He thought Amitabh stating this only indicated that Amitabh was only concerned about himself and not Parveen's health. This would lead to several years of Mahesh bashing Amitabh in the press.
Zeenat Aman played the sole heroine with two competing heroes in 3 movies in 1980. Dostana with Amit & Shatru, Qurbani with Vinod Khanna and Feroz, and Bombay 405 miles with Shatru & Vinod Khanna.
Veteran actress Ruby Meyers played a nun.
When Raj Khosla started the film he stated he had the perfect star cast. Amitabh Bachchan and Vinod Khanna were to play parallel leads. But when Raj Khosla finally read Salim Javed's full script, he realized that Vinod Khanna had no role in the film. It was Amitabh's show all the way. The right choice would be Shatrughan Sinha. Raj Khosla told this to Yash Johar. He removed Vinod from the film despite Vinod being a bigger star and more talented than Shatrughan. These were the exact words Khosla used in a interview in Filmfare magazine.
This is one of those rare films where Amitabh Bachchan is shown chewing bubble gum all the while.