Accidentally Took Two Seroquel During The Day Instead Of One

In our latest question and answer, the pharmacist discusses concerns after accidentally taking two doses of quetiapine in one day.

3 min read Updated Jun 2026 Read by 4,389 people
Accidentally Took Two Seroquel During The Day Instead Of One
Share
Linnea asked

I usually take 150 mg of quetiapine at night and 100 mg of lamotrigine in the morning. However, this morning, I accidentally took my quetiapine again instead of the lamotrigine. Should I be concerned?

Jul 24, 2023
The quick answer
  • Taking an extra dose of quetiapine in the morning may cause increased drowsiness or sedation, so avoid driving or operating machinery until you feel comfortable.
  • Common side effects from the accidental extra dose may include dry mouth, constipation, or headache.
  • Seek immediate medical attention if you experience severe symptoms like rapid heart rate, persistent dizziness, severe confusion, agitation, or difficulty breathing.
A quick summary of Dr. Brian Staiger, PharmD's full answer below, condensed by AI from that answer only (not from any outside source). The pharmacist's answer is the source of record.
Medications in this answer — tap to explore

Answer

I certainly understand your concern about accidentally taking an extra dose of quetiapine (generic for Seroquel) in the morning instead of lamotrigine. While everyone's medical situation is different, for most individuals, taking 300 mg of quetiapine instead of your usual 150mg is not a significant cause for alarm.

Having said this, and before getting into more detail, I always like to say it is better to always err on the side of caution and if you are feeling unwell, please seek medical attention or at the very least contact Poison Control (Poison.org; 1-800-222-1222) for personalized advice.

What To Expect

It is important to note that the maximum recommended daily dosage of quetiapine noted in the prescribing information for the drug is 800mg. Various studies indicate that doses up to 800mg per day can be tolerated when prescribed for certain conditions such as bipolar disorder or schizophrenia. However, since you are not accustomed to taking a higher dose of quetiapine, it's certainly possible you may experience some side effects, and therefore, it is important to monitor for any.

One of the most common side effects of quetiapine, especially with a higher dosage, is sedation or excessive drowsiness.

It is normal to experience increased sedation and feel more tired due to a higher dose. If you encounter this side effect, be sure to avoid activities like driving a vehicle or operating machinery until you feel comfortable.

Other common side effects of the drug include dry mouth, constipation and headache.

While it is unlikely that you will experience any major issues with an accidental increase in your quetiapine dosage, it is essential to be aware of any potential severe side effects. These could include:

  • Rapid increase in heart rate
  • Persistent dizziness
  • Severe confusion
  • Agitation
  • Difficulty breathing

If you encounter any of these severe symptoms, it is crucial to seek immediate medical attention.

Considering the circumstances, it would be advisable to contact a healthcare professional, such as your prescribing doctor or your pharmacist where you get your medication.

They can provide personalized guidance regarding your situation, take into account your medical history, and offer appropriate recommendations based on your individual needs.

Final Words

In conclusion, while accidentally taking more medication than prescribed can cause concerns, the increase in quetiapine dosage you described is within the acceptable range and is not likely to pose a significant danger for most individuals.

However, it's crucial to be mindful of side effects, particularly sedation, and adjust your daily activities accordingly. If more severe side effects occur, seek medical attention.

Additionally, contacting a healthcare professional who knows your medical history would be prudent to seek their guidance based on your specific medical situation.

References & sources
  1. Seroquel Prescribing Information — AccessFDA
  2. Quetiapine: dose-response relationship in schizophrenia — AccessFDA
Glossary — Terms in This Answer
Quetiapine
An antipsychotic medication used to treat conditions like bipolar disorder and schizophrenia.
Lamotrigine
A mood-stabilizing medication commonly used to treat bipolar disorder and seizures.
Dosage
The specific amount of a medication prescribed to be taken at one time or over a period.
Sedation
A state of reduced consciousness or drowsiness caused by medication.
Side effects
Unwanted or harmful reactions that occur in addition to the intended therapeutic effect of a medication.
Bipolar disorder
A mental health condition characterized by extreme mood swings between depressive and manic episodes.
Schizophrenia
A serious mental disorder that affects how a person thinks, feels, and perceives reality.
Prescribing information
Official documentation that outlines a drug's approved uses, dosages, side effects, and safety guidelines.
Did this answer your question?
Dr. Brian Staiger, PharmD
About the pharmacist

Dr. Brian Staiger, PharmD

Clinical Pharmacy

Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified

Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...

More answers from Brian →
Ask a Pharmacist