FAQ for
Fantastic Voyage (1966)

No. Isaac Asimov wrote a novelization of this film's screenplay. The book was released six months before the movie. You can buy the book at Amazon here.

Note that Asimov also wrote Fantastic Voyage II: Destination Brain, published in 1987. That book is not a sequel to the original story; it's more of a remake. Asimov retains the central premise and creates a new story around it.

No. You may be thinking of Innerspace (1987), with Dennis Quaid as a cocky pilot in a submarine-like ship that is miniaturized and, through a series of mishaps, injected into the bloodstream of a hypochondriac store clerk (Martin Short).