Quetiapine is a dibenzothiazepine derivative with the antipsychotic property. Quetiapine fumarate antagonizes serotonin activity mediated by 5-HT 1A and 5-HT2 receptors. With a lower affinity, this agent also reversibly binds to dopamine D1 and D2 receptors in the mesolimbic and mesocortical areas of the brain leading to decreased psychotic effects, such as hallucinations and delusions. In addition, quetiapine also binds to other alpha-1, alpha-2 adrenergic and histamine H1 receptors.
Quetiapine is indicated for the treatment of schizophrenia as well as for the treatment of acute manic episodes associated with bipolar I disorder. Quetiapine also has an antagonistic effect on the histamine H1 receptor.It is an atypical antipsychotic used for the treatment of schizophrenia, bipolar disorder, and major depressive disorder. It is also sometimes used as a sleep aid due to its sedating effect, but this use is not recommended. It is taken by mouth.
Mechanism of Action of Quetiapine
Quetiapine’s antipsychotic activity is likely due to a combination of antagonism at D2 receptors in the mesolimbic pathway and 5HT2A receptors in the frontal cortex. Antagonism at D2 receptors relieves positive symptoms while antagonism at 5HT2A receptors relieves negative symptoms of schizophrenia. Quetiapine is a selective monoaminergic antagonist with high affinity for the serotonin Type 2 (5HT2), and dopamine type 2 (D2) receptors. Quetiapine is an antagonist at serotonin 5-HT1A and 5HT2, dopamine D1 and D2, histamine H1, and adrenergic alpha 1 and alpha 2 receptors. Quetiapine has no significant affinity for cholinergic muscarinic or benzodiazepine receptors. Drowsiness and orthostatic hypotension associated with the use of quetiapine may be explained by its antagonism of histamine H1 and adrenergic alpha 1 receptors, respectively. Quetiapine’s antagonism of adrenergic a1 receptors may explain the orthostatic hypotension observed with this drug.
Indications of Quetiapine
- Bipolar disorder
- Generalized anxiety disorder
- Borderline personality disorder
- Depression
- Schizoaffective disorder
- Schizophrenia
- Insomnia
- Intermittent explosive disorder
- Major depressive disorder
- Obsessive-compulsive disorder
- Paranoid disorder
- Post-traumatic stress disorder
- Tourette’s syndrome
- Acute depressive Episode
- Bipolar I disorder
- Delusional parasitosis
- Mixed manic depressive episode
- Psychosis
- Treatment of bipolar disorder
- Treatment of moderate to severe manic episodes in bipolar disorder
- Treatment of major depressive episodes in bipolar disorder
- Prevention of recurrence of manic or depressed episodes in patients with bipolar disorder who previously responded to quetiapine treatment.
- Tardive dyskinesia
- Acute manic episode
Contra Indications of Quetiapine
- Diabetes
- Increased prolactin in the blood
- High cholesterol
- High amount of triglyceride in the blood
- Excessive fat in the blood
- Low amount of magnesium in the blood
- Extreme loss of body water
- Low amount of potassium in the blood
- Anemia
- Deficiency of granulocytes a Type of white blood Cell
- Decreased white blood cells
- Decreased neutrophils a Type of white blood Cell
- Having thoughts of suicide
- Abnormal Movements of Face Muscles and Tongue
- Extrapyramidal reaction
- Neuroleptic malignant syndrome
- Lower seizure threshold
- Cataracts
- high blood pressure
- Heart attack
- Disease of inadequate blood flow to the heart muscle
- Very rapid heartbeat – torsades de Pointes
- Slow heartbeat
- prolonged QT interval on EKG
- abnormal heart rhythm
- Chronic heart failure
- Abnormal EKG with QT changes from birth
- Disorder of the blood vessels of the brain
- Blood Pressure drop upon standing
- Liver problems
- seizures
- Weight gain
- High blood sugar
- Abnormal liver function tests
- Weakened patient
- Susceptible to Breathing fluid into the lungs
- Dementia in an elderly person
Dosage of Quetiapine
Strengths: 25 mg; 100 mg; 200 mg; 300 mg; 50 mg; 400 mg; 150 mg
Schizophrenia
Immediate-release tablets
- Day 1: 25 mg orally twice a day
- Days 2 and 3: Increase in 25 to 50 mg increments divided 2 or 3 times daily with the goal of achieving a total daily dose of 300 to 400 mg by day 4
- Further dose adjustments should be made in 25 to 50 mg increments twice a day in intervals of not less than 2 days
- Recommended dose: 150 to 750 mg orally per day in divided doses
- Maximum dose: 750 mg/day
Extended-release (XR) tablets
- Day 1: 300 mg orally once a day
- Increase in increments of up to 300 mg/day
- Recommended dose: 400 to 800 mg orally once a day
- Maximum dose: 800 mg/day
Pediatric Bipolar Disorder
Age: 10 to 17 years:
Special Considerations in Treating Pediatric Bipolar 1 Disorder
- Prior to initiating medication therapy, a thorough diagnostic evaluation carefully considering the risks associated with medication treatment should be performed.
- Medication treatment should be a part of a total treatment program that often includes psychological, educational, and social interventions.
Depression
Extended-release (XR) tablets
- Initial dose: 50 mg orally once a day
- Dose increases should be made in increments of 50 mg/day depending on clinical response and tolerabilit
- Recommended dose: 150 mg to 300 mg orally once a day
- Maximum dose: 300 mg/day
Bipolar Disorder
MANIA Associated with Bipolar Disorder (as monotherapy or as an adjunct therapy to lithium or divalproex)
Immediate-release (IR) tablets
- Initial dose: 25 mg orally twice a day
- Dose increases should be made in increments of 50 mg/day depending on clinical response and tolerability
- Recommended dose: 400 to 800 mg orally per day in divided doses
- Maximum dose: 800 mg/day
Extended-release (XR) tablets
- Initial dose: 50 mg orally once a day
- Dose increases should be made in increments of 50 mg/day depending on clinical response and tolerability
- Recommended dose: 400 to 800 mg/day
- Maximum dose: 800 mg/day
DEPRESSIVE Episodes Associated with Bipolar Disorder
Immediate-release (IR) tablets
- flatulence,
- Initial dose: 25 mg orally twice a day
- Dose increases should be made in increments of 50 mg/day depending on clinical response and tolerability
- Recommended dose: 300 mg/day
- Maximum dose: 300 mg/day
Extended-release (XR) tablets
- Initial dose: 50 mg orally once a day
- Dose increases should be made in increments of 50 mg/day depending on clinical response and tolerability
- Recommended dose: 300 mg/day
- Maximum dose: 300 mg/day
Side Effects of Quetiapine
The most common
- Dry mouth
- Dizziness
- Hypertension
- chest pain
- certainly hair loss
- headache
- joint painPain
- dizziness
- nausea and vomiting
- Severe stomach ache
- epigastric pain,
- diarrhoea,
- anorexia,
- flatulence,
- headache,
- dizziness,
- fainting, fast or pounding heartbeats.
More common
- Fast or irregular heartbeat
- appetite loss
- changes in nails
- constipation
- fatigue
- fever
- Back pain
- dizziness
- headache
- increased cough
- Acid or sour stomach
- decreased appetite
- Agitation
- chest congestion
- chest pain
- cold sweats
- confusion
- decreased sexual ability or desire
- stomach or abdominal cramps, gas, or pain
- trouble sleeping
Less common
- bleeding gums
- blood in the urine or stools
- chest pain
- diarrhea
- Burning, crawling, itching, numbness, prickling, “pins and needles“, or tingling feelings
- difficulty in moving
- muscle stiffness
- redness of the face, neck, arms and occasionally, upper chest
- lack or loss of strength
- muscle spasm
- difficult or labored breathing
- dry mouth
- headache
- irritability
- lack or loss of strength
- loose stools
- loss of interest or pleasure
- muscle stiffness
- night sweats
- passing gas
- stomach discomfort, upset, or pain
- swollen joints
- trouble concentrating
- increased blood pressure
Drug Interactions of Quetiapine
Quetiapine acetate may interact with following drugs, supplements & may decrease the efficacy of the drug
- angiotensin converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
- angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
- antiseizure medications (e.g., carbamazepine, phenobarbital, phenytoin)
- antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
- “azole” antifungal medications (e.g., fluconazole, ketoconazole)
- baclofen
- barbiturates (e.g., butalbital, pentobarbital phenobarbital)
- benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
- beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
- calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
- cyclosporine
- diuretics (water pills; e.g., furosemide, hydrochlorothiazide, )
- domperidone
- macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
- selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, duloxetine, fluoxetine, paroxetine, sertraline)
- serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
- serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine,duloxetine, venlafaxine)
- tamoxifen
- tapentadol
- tetracycline
- thiazide diuretics (water pills; e.g., hydrochlorothiazide, indapamide, metolazone)
- tramadol
- tricyclic antidepressants (e.g., amitriptyline, clomipramine, trimipramine)
- trimethoprim
- tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib)
- vardenafil
- warfarin
Pregnancy & Lactation of Quetiapine
FDA Pregnancy Catagory C
Pregnancy
The safety of quetiapine use during pregnancy is not known. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Lactation
This medication passes into breast milk. If you are a breastfeeding mother and are taking quetiapine it may affect yo ur baby.Talk to your doctor about whether you should continue breastfeeding. The safety and efficacy of this medication have not been established for children under 18 years of age.
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