Nathan Price, 28, of Common Edge Road, Blackpool, crashed into the back of a vehicle, causing it to flip, as he weaved in and out of traffic on the southbound M61 near junction 9.
At the time he had seven times the legally permitted amount of a cocaine derivative in his body.
In addition to the jail term, a judge at Bolton Crown Court disqualified him from the roads for six years.
The collision, at 10.30am on April 14, saw the motorway closed for seven hours as emergency crews assisted the victims.
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He also had a broken finger, ligament ruptures, and was left with tilted vision and hearing problems.
The woman, who was a rear seat passenger, suffered a fractured spine, bruising to her shoulders and hips, and needed a temporary catheter.
Price previously appeared before Preston Magistrates’ Court where he admitted two counts of causing serious injury by dangerous driving, drug driving and driving without insurance.
At the time a prosecutor said: “ The defendant has been driving in a dangerous manner, swerving in and out of traffic and exceeding the speed limit.”