Three double blinded trials (787 participants) were included in the review: two in patients with schizophrenia (one phase II trial and one phase III trial) and one in patients with bipolar disorder (phase III trial).
Inhaled loxapine (5mg and 10mg) appeared to be superior to placebo two hours following the initial dose.
In the phase two trial there were 22 out of 45 responders in the 5mg group and 25 out of 40 responders in the 10mg group compared with nine out of 43 in the placebo group.
In one of the phase three trials (patients with schizophrenia) there were 66 out of 116 responders in the 5mg group and 75 out of 112 responders in the 10mg group compared with 41 out of 115 in the placebo group. In the other phase three trial (patients with bipolar disorder) 66% of participants were responders in the 5mg group and 74% in the 10mg group compared with 28% in the placebo group.
In pooled analysis, the NNT for response to 5mg of inhaled loxapine was four (NNT=4, 95% CI 3 to 5) and for 10mg was three (NNT=3, 95%CI 3 to 4).
The most common adverse event was dysgeusia (disordered taste sense)