Loxapine (Loxitane, Adasuve)

What it treats

Oral loxapine is FDA-approved for schizophrenia. Adasuve (inhaled loxapine) is approved for acute agitation associated with schizophrenia or bipolar I disorder in adults. The inhaled form is only used in healthcare settings enrolled in a REMS safety program because of the bronchospasm risk.

How it works

Loxapine is a dibenzoxazepine, structurally close to clozapine. It blocks dopamine D2 receptors, which is the main antipsychotic action, and it also blocks serotonin 5-HT2A receptors, which gives it some atypical-like features. That mixed activity may soften some movement side effects compared with pure high-potency first-generation drugs, though loxapine is still classed as a first-generation antipsychotic and still carries meaningful tardive dyskinesia risk.

Receptor mechanism (detail)

Loxapine is a D2 and 5-HT2A antagonist. Its 5-HT2A activity is why some clinicians consider it a first-generation drug with atypical-like features. It also has moderate H1, muscarinic, and alpha-1 blockade, giving it some sedation and mild orthostatic effect. Its metabolite amoxapine (which is marketed separately as a tetracyclic antidepressant) may contribute to some clinical effects.

Potency and typical dosing pattern

Ranges are typical framework only, not a prescription for any individual.

For oral schizophrenia treatment, a common starting dose is 10 mg twice daily. Usual maintenance sits at 60 to 100 mg per day divided in two or three doses. For acute agitation using Adasuve, one 10 mg inhalation is given as a single dose, only in a healthcare setting where staff are prepared to manage bronchospasm and where the person has been screened for reactive airway disease. The prescriber sets and adjusts the oral dose based on response and side effects.

Safety monitoring

• For inhaled Adasuve, screen for asthma, COPD, or other airway disease before use. Continuous monitoring for wheeze or shortness of breath in the hour after administration. A short-acting bronchodilator must be available.
• Involuntary-movement screen (AIMS) every six months for tardive dyskinesia.
• Movement side-effect check at each early visit.
• Metabolic labs, weight, BMI, fasting glucose or HbA1c, and lipids at baseline and annually.
• Blood pressure at baseline and periodically.
• Prolactin if symptoms appear.

Metformin co-commencement: Aoife Carolan / Schizophrenia Bulletin guideline.

A clinical guideline led by Aoife Carolan strongly recommends co-commencing metformin alongside high-risk antipsychotics like olanzapine or clozapine. This proactive approach helps mitigate severe metabolic side effects, significantly reducing antipsychotic-induced weight gain and improving insulin resistance. The Schizophrenia Bulletin guideline states that when prescribing olanzapine or clozapine, metformin should be initiated immediately to prevent weight gain and cardiometabolic issues. Loxapine is a first-generation antipsychotic and isn't on the automatic co-commencement list, but metformin is recommended if weight rises more than 3 percent of pre-medication weight or if other cardiometabolic risk factors are present.

Typical titration used in the guideline: 500 mg once daily, then 500 mg twice daily after one week, then 500 mg increments every two weeks as tolerated, up to 1000 mg twice daily by about week six. Contraindicated with eGFR below 30 mL/min/1.73 m². Renal function is checked annually and metformin is held during acute illness or dehydration.

Source: Carolan A, et al. Metformin for the Prevention of Antipsychotic-Induced Weight Gain: Guideline Development and Consensus Validation. Schizophrenia Bulletin. 2025;51(5):1193 to 1203.

What to expect

Common side effects

• Sedation, especially at higher oral doses.
• Movement side effects, parkinsonism, akathisia.
• Dry mouth and mild constipation.
• Orthostatic hypotension.
• Weight gain, moderate.
• For inhaled Adasuve, throat irritation and altered taste are common. Bronchospasm is uncommon but can be dangerous.

Serious side effects and warnings

Boxed warning. Loxapine carries the FDA boxed warning that antipsychotics increase the risk of death in older adults with dementia-related psychosis. Adasuve inhaled additionally carries a boxed warning for bronchospasm.

• Bronchospasm (Adasuve). The main reason Adasuve is REMS-restricted. Screen for airway disease before use. Short-acting bronchodilator must be immediately available.
• Tardive dyskinesia. Long-term antipsychotic use can produce involuntary movements. Risk rises with dose and duration.
• Neuroleptic malignant syndrome. Rare but serious. A medical emergency.
• Seizure threshold lowering, relevant in epilepsy.
• QTc prolongation at higher doses.

This isn't medical advice. Any concern about a serious side effect should be raised with a prescriber promptly.

Sexual side effects

Loxapine can affect sex drive and function, partly through prolactin elevation. If sexual side effects appear, it's worth raising with the prescriber.

Weight, appetite, and sleep

Weight gain with oral loxapine tends to be moderate. Sedation often helps sleep. If daytime sedation is heavy, dose timing changes may help.

Starting and dosing basics

This section is general background, not a dosing instruction. Oral loxapine comes as capsules. Adasuve comes as a single-use inhaler used only in enrolled healthcare settings. The prescriber chooses the right form and dose for the situation.

Missed doses and interactions

If you miss an oral dose, take it when you remember unless it's almost time for the next one, then skip and carry on. Don't double up. Loxapine interacts with other CNS depressants and anticholinergic drugs. The prescriber and pharmacist need a full list of medications and supplements. Alcohol worsens sedation.

Stopping and tapering

Don't stop oral loxapine abruptly. A prescriber can step the dose down gradually.

Pregnancy and breastfeeding

Untreated psychosis carries its own risks in pregnancy, and loxapine passes into breast milk. Anyone who's pregnant, planning a pregnancy, or breastfeeding should talk it through with their prescriber. This isn't medical advice.

Cost and generic availability

Oral loxapine is generic and inexpensive. Adasuve is brand-only and considerably more expensive; its use is limited to hospitals and clinics enrolled in the REMS program.

Common questions

Is loxapine a first-generation or an atypical drug? It's classed as first-generation, but its serotonin 5-HT2A activity gives it some atypical-like features. That doesn't mean it avoids tardive dyskinesia risk or metabolic effects, just that its receptor profile is a bit less pure than haloperidol.

What's special about the inhaled form? Adasuve delivers loxapine directly to the lungs, where it's absorbed within minutes. That fast onset is useful for acute agitation, but the inhalation itself can trigger bronchospasm in people with reactive airway disease. That's why it's only used in enrolled healthcare settings.

Why not use it more often? The oral form works but has no clear advantage over other antipsychotics, so it doesn't come up often. Adasuve is niche because of the REMS requirement.

Is it related to clozapine? Chemically yes, they're both dibenzoxazepines. Clinically loxapine doesn't have clozapine's unique effectiveness in treatment-resistant schizophrenia and doesn't require white blood cell monitoring.

Questions to ask your prescriber

• What are we hoping this treats, and how will we know it's working?
• Am I a candidate for the inhaled form if I ever need it?
• What movement side effects should I watch for?
• How much sedation should I expect?
• If we decide to stop it later, how would we taper safely?

Sources

This guide draws on current prescribing information and public health references. It is reviewed for clinical accuracy and updated as guidance changes, and current as of June 8, 2026.

• U.S. Food and Drug Administration. Loxapine and Adasuve prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Loxapine.
• Adasuve REMS Program (U.S. Food and Drug Administration).
• American Psychiatric Association. Practice Guideline for the Treatment of Patients with Schizophrenia, 3rd edition.
• National Institute for Health and Care Excellence (NICE). CG178, Psychosis and schizophrenia in adults.
• Carolan A, et al. Metformin for the Prevention of Antipsychotic-Induced Weight Gain: Guideline Development and Consensus Validation. Schizophrenia Bulletin. 2025;51(5):1193 to 1203.