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Quetiapine; Uses, Dosage, Side Effects, Interaction, Pregnancy

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-HT_1A 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

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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

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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

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

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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.