Molindone (Moban)

What it treats

Molindone is FDA-approved for schizophrenia. It isn't a common first choice today, and its supply has been on and off in the U.S. market. The main reason a prescriber might reach for it is a person who's had significant weight gain on other antipsychotics and needs an alternative that won't add to it.

How it works

Molindone is a dihydroindolone first-generation antipsychotic. It blocks dopamine at the D2 receptor, which is the standard antipsychotic mechanism, and it has relatively little activity at histamine, muscarinic, or serotonin receptors. That receptor profile is why molindone doesn't drive appetite the way most antipsychotics do.

Receptor mechanism (detail)

Molindone is a D2 receptor antagonist with minimal H1 histamine blockade and minimal 5-HT2C activity. The absence of these two mechanisms is thought to explain why it doesn't cause the appetite increase and weight gain typical of the antipsychotic class. It does raise prolactin, and it can cause extrapyramidal side effects.

Potency and typical dosing pattern

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

A common range for schizophrenia is 15 to 100 mg per day, divided into three or four doses. Higher doses (up to 225 mg per day) have been used in acute treatment. The prescriber sets and adjusts the dose based on response and side effects.

Safety monitoring

• Involuntary-movement screen (AIMS) every six months.
• Movement side-effect check at each early visit.
• Metabolic labs, weight, BMI, fasting glucose or HbA1c, and lipids at baseline and annually. Even though molindone tends to be weight-neutral, checking is still worthwhile.
• 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. Molindone is a first-generation antipsychotic and, unusually for this class, is often weight-neutral or weight-losing, so automatic co-commencement isn't part of standard practice. Metformin is still worth considering if weight rises more than 3 percent 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

• Mild sedation.
• Parkinsonism, tremor, stiffness.
• Akathisia.
• Dry mouth, mild.
• Raised prolactin.
• Nausea, especially early.

Serious side effects and warnings

Boxed warning. Molindone carries the FDA boxed warning that antipsychotics increase the risk of death in older adults with dementia-related psychosis, and it isn't approved for that use.

• 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.
• Acute dystonic reactions, treatable and usually reversible.
• QTc prolongation at higher doses.
• Seizure threshold lowering, relevant in epilepsy.

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

Sexual side effects

Molindone 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

This is where molindone is different. Appetite typically doesn't rise, and many people either hold weight steady or lose a small amount. That makes it a distinctive option when weight gain from other antipsychotics has been a problem. Sleep is usually minimally affected.

Starting and dosing basics

This section is general background, not a dosing instruction. Molindone comes as tablets. It can be taken with or without food. U.S. supply has been intermittent, and availability should be confirmed before choosing it.

Missed doses and interactions

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

Stopping and tapering

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

Pregnancy and breastfeeding

Untreated psychosis carries its own risks in pregnancy, and molindone 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

Molindone is generic. Availability in the U.S. has come and gone over the years, and it isn't always stocked. Confirm supply before starting.

Common questions

Why is molindone described as weight-neutral? Most antipsychotics drive appetite through histamine H1 and serotonin 5-HT2C blockade. Molindone has minimal activity at both, so appetite typically doesn't rise. That's why it stands out in the class.

Is it as effective as other antipsychotics? Efficacy for schizophrenia is comparable with other first-generation antipsychotics. The trade-off has been availability, not effectiveness.

Does it still cause movement side effects? Yes. Movement side effects and tardive dyskinesia risk are similar to other first-generation antipsychotics. The metabolic profile is what sets it apart, not the movement profile.

Why isn't it used more? Supply issues and the arrival of atypical antipsychotics both pushed it aside. When newer antipsychotics have gentler movement profiles, prescribers usually reach for those first. Molindone comes up mostly when metabolic side effects have been the main problem.

Questions to ask your prescriber

• Are we choosing molindone specifically for its weight profile?
• Is it available at the pharmacy where I fill my prescriptions?
• What movement side effects should I watch for?
• If it isn't available later, what's a reasonable alternative?
• 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. Molindone prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Molindone.
• National Institute of Mental Health. Mental health medications.
• 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.