Caplyta Side Effects: What to Expect and When to Call Your Doctor

Updated:

February 15, 2026

Author:

Peter Daggett

Summarize this blog with AI:

A complete guide to Caplyta (lumateperone) side effects — common, serious, and rare. Know what to expect and when to seek medical help.

Understanding Caplyta Side Effects

Caplyta (lumateperone) is an atypical antipsychotic used to treat schizophrenia, bipolar depression, and as an add-on therapy for major depressive disorder (MDD). Like all medications in this class, it comes with potential side effects — but many people tolerate Caplyta well compared to older antipsychotics.

This guide covers the most common side effects, the serious ones to watch for, and clear guidance on when you should call your doctor.

Common Side Effects of Caplyta

Most people who take Caplyta experience mild side effects that often improve within the first few weeks. The most frequently reported include:

  • Sleepiness or sedation — reported by 12% to 24% of patients. This is the most common side effect.
  • Dizziness — affects up to 17% of patients, especially when standing up quickly
  • Dry mouth — reported in up to 13% of patients
  • Nausea — affects up to 9% of patients
  • Fatigue — reported in up to 8% of patients
  • Diarrhea — affects up to 5% of patients
  • Decreased appetite
  • Vomiting

These side effects are generally manageable. If sleepiness is a problem, talk to your doctor about taking Caplyta at bedtime instead of in the morning.

Tips for Managing Common Side Effects

Here are some practical ways to handle the most common Caplyta side effects:

For Sleepiness and Fatigue

  • Take Caplyta in the evening or at bedtime
  • Avoid alcohol and other sedating medications
  • Give your body 1 to 2 weeks to adjust — drowsiness often improves over time

For Dizziness

  • Stand up slowly from sitting or lying positions
  • Stay hydrated throughout the day
  • Avoid hot showers or baths, which can worsen dizziness

For Dry Mouth

  • Sip water frequently
  • Chew sugar-free gum or suck on sugar-free candy
  • Use an alcohol-free mouthwash designed for dry mouth

For Nausea

  • Take Caplyta with a small snack or meal
  • Avoid spicy or greasy foods right after taking the capsule
  • Nausea usually improves within the first week

Serious Side Effects: When to Call Your Doctor

Some side effects of Caplyta are serious and require immediate medical attention. Contact your doctor right away if you experience any of the following:

Neuroleptic Malignant Syndrome (NMS)

This is a rare but life-threatening reaction to antipsychotics. Symptoms include:

  • Very high fever
  • Severe muscle stiffness
  • Confusion or altered mental state
  • Rapid or irregular heartbeat
  • Excessive sweating

If you notice these symptoms, call 911 or go to the emergency room immediately.

Tardive Dyskinesia

This condition causes involuntary, repetitive movements — usually in the face, tongue, or jaw. It can develop after weeks, months, or even years of treatment. Tell your doctor if you notice any unusual movements you can't control.

Metabolic Changes

Caplyta can affect your blood sugar, cholesterol, and weight. Your doctor should monitor these with regular blood tests. Watch for:

  • Unusual thirst or frequent urination (signs of high blood sugar)
  • Significant weight gain
  • Feeling very hungry all the time

Orthostatic Hypotension

A sudden drop in blood pressure when you stand up can cause dizziness, lightheadedness, or fainting. This is more common when you first start Caplyta. If you faint or feel like you're going to faint, call your doctor.

Low White Blood Cell Count

Caplyta can reduce your white blood cells, making it harder to fight infections. Call your doctor if you develop:

  • Fever
  • Sore throat that won't go away
  • Mouth sores
  • Signs of infection

Serotonin Syndrome

If you take Caplyta with other serotonergic drugs (like SSRIs or SNRIs), there's a risk of serotonin syndrome. Symptoms include:

  • Agitation or restlessness
  • Rapid heartbeat
  • High body temperature
  • Muscle twitching or loss of coordination
  • Diarrhea

Serotonin syndrome is a medical emergency. Seek help immediately.

Important Boxed Warnings

Caplyta carries two FDA boxed warnings — the most serious type of warning:

  1. Elderly patients with dementia-related psychosis who take antipsychotics have an increased risk of death. Caplyta is not approved for this use.
  2. Increased risk of suicidal thoughts and behaviors in children, teens, and young adults (under 25) taking antidepressants. While Caplyta is only approved for adults, this warning applies to its use for depression.

If you or someone you know is having suicidal thoughts, contact the 988 Suicide and Crisis Lifeline by calling or texting 988.

Side Effects Compared to Other Medications

One reason doctors choose Caplyta is that it tends to cause fewer metabolic side effects than many other atypical antipsychotics. Compared to medications like Seroquel (quetiapine) or Zyprexa (olanzapine), Caplyta generally causes:

  • Less weight gain
  • Fewer blood sugar problems
  • Less sedation (though drowsiness is still common)

That said, every person responds differently. If you're curious about how Caplyta compares to alternatives, read our guide on alternatives to Caplyta.

How Long Do Side Effects Last?

Most common side effects (drowsiness, dizziness, dry mouth) improve within the first 1 to 2 weeks as your body adjusts. If side effects don't improve after 2 to 4 weeks, talk to your doctor. They may adjust your dose or explore other options.

Serious side effects like tardive dyskinesia can develop at any time during treatment and may not go away even after stopping the medication, which is why regular check-ups with your prescriber are important.

Talk to Your Doctor — Don't Stop Caplyta on Your Own

If you're experiencing bothersome side effects, it can be tempting to stop taking Caplyta. But stopping an antipsychotic suddenly can cause withdrawal symptoms or a relapse of your condition. Always talk to your doctor before making any changes to your medication.

Your doctor can help you weigh the benefits against the side effects and decide on the best path forward.

Related Articles

What is the most common side effect of Caplyta?

Sleepiness (somnolence) is the most common side effect of Caplyta, affecting 12% to 24% of patients. Taking Caplyta at bedtime can help reduce daytime drowsiness.

Does Caplyta cause weight gain?

Caplyta can cause some weight gain, but it generally causes less weight gain than many other atypical antipsychotics like quetiapine or olanzapine. Your doctor should monitor your weight and metabolic markers during treatment.

How long do Caplyta side effects last?

Most common side effects like drowsiness, dizziness, and dry mouth improve within 1 to 2 weeks as your body adjusts. If side effects persist beyond 2 to 4 weeks, talk to your doctor about adjusting your treatment.

Can I stop taking Caplyta if I have bad side effects?

Never stop taking Caplyta suddenly without talking to your doctor first. Stopping an antipsychotic abruptly can cause withdrawal symptoms or a relapse of your condition. Your doctor can help you safely taper off or switch to a different medication.

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