The new, non-injectable therapy uses Alexza's proprietary Staccato hand-held inhaler, with the antipsychotic drug, loxapine.
The company said the inhaler delivers a drug aerosol to the deep lung that results in rapid systemic delivery and absorption.
"The approval of Adasuve is an important event in the treatment of agitation," said president and CEO Thomas B. King.
"This is a landmark day for Alexza and we are proud of our accomplishments in developing this unique product. We project that Adasuve will be available for commercial launch early in the third quarter of 2013."
Alaza said that the FDA approval is based on clinical data from more than 1,600 patients and subjects. In two phase 3 trials, Adasuve was found to be effective and met the primary efficacy endpoint, with "statistically significant" reductions in agitation as compared to placebo.
Of note, said the company, was that the therapy produced results within about 10 minutes.
Adasuve can, however, cause bronchospasm, which has the potential to lead to respiratory distress and respiratory arrest, and so will only be offered through a restricted program.
As part of the recent approval, Alexza said the drug also has "several post-approval requirements", including futher clinical trials to determine the safety of the treatment in adolescents.
Alexza is a pharmaceutical company focused on the research, development and commercialization of products for the acute treatment of central nervous system conditions.
Adasuve is Alexza's lead therapeutic program. Earlier this month, the company received "a positive opinion" from the European Medical Association, recommending the approval of Adasuve in the European Union.
The company noted that the European Commission is now expected to grant marketing authorization for Adasuve in all 27 European Union Member States, plus Iceland, Lichtenstein and Norway.
A decision is expected from the European Commission in the first quarter of 2013.