Quetiapine is a first-line atypical antipsychotic that has been used since 1998 for schizophrenia, bipolar disorder, depression, and other conditions. It is absorbed quickly in the body and metabolized in the liver. Quetiapine acts as an antagonist at serotonin, histamine, alpha-1, and dopamine receptors, with varying degrees of affinity. Common side effects include sedation, dizziness, hypotension, weight gain, and metabolic changes. Overdoses may cause lethargy, tachycardia, respiratory issues, and other symptoms, but are typically not fatal.

1. QUETIAPINE

2.  Since it’s release in 1998, quetiapine has become a
first line SGA medication.
 It is a dibenzothiazepine antipsychotic with more
5HT2 than D2 receptor blocking properties.
 Quetiapine was developed by Zeneca laboratories.
 approved by FDA in 1998
 It’s molecular formula Is
C42H50N6O4S2.C4H4O4

3.  Pharmacokinetics-
 Absorption & distribution –
 The time to maximum concentration after oral intake is 1.5
hours with an estimated half-life of 6 hour.
 No difference was found between twice & three times daily
dosing, inspite of a steady-state half life of 6.9 hours.
 Steady-state levels are reduced in 48 hour.

4.  Metabolized by liver.
 It has many metabolites, although only a
small % of these are active.
 The primary metabolic pathway is though
CYP34A

5.  Quetiapine is a multi transmitter
antipsychotic agent.
 It has high affinity for 5-HT2, histamine H1,
ALFA 1 & ALFA 2 receptors, a moderate
affinity for 5-HT1A receptors & D2
receptors and low affinity for D1 receptors.
 Quetiapine has a very low affinity for
cholinergic M1 & D2 receptors.

6. • Sedative
• Anxiolytic
• Antimanic
• Mood-stabilizing
• Antidressant
Mechanism of action of quetiapine
involves 5-HT2A/D2 antagonism and 5-
HT1A partial agonism.
H1 and alpha 1 antagonism are linked to
side effects

7.  Acute Schizophrenia in adults & ages 13-17
years
 Schizophrenia maintenance
 Acute Mania in adults & ages 10-17 years
 Bipolar maintenance
 Bipolar depression

8.  Mixed mania
 Behavioral disturbance in dementias
 Behavioral disturbance in Parkinson’s disease
and Lewy body dementia
 Behavioral disturbances in children and
adolescents
 Disorders associated with impulse control
 Severe treatment resistant anxiety

9. Dosage guideline:
Initial dose of 25mg bid, with increase in increments of
25-50 mg on second and third day as tolerated, to a target
dose of 300-400 mg by fourth day
depending on clinical response and tolerability dose may
be adjusted within range of 300-800 mg/day
Initial gradual upward titration is helpful to reduce
side effects

10.  ELDER POPULATION-
 In this population orthostatic hypotension or
syncope can increase the risk of falls.
 The titration schedule in the elderly should be
showed & the target dose lower
 Initial doses should be 12.5 mg to 25 mg per day
& increments of no more than 25 mg should
occur every 1-3 days, depending on tolerability.

11.  Patient with hepatic impairment should be
initiated at doses no higher than 25mg per
day .
 The dose can be increased daily by 25-50 mg
to an effective dose.

12.  Quetiapine is metabolized by the
cytochrome P450 system.
 Quetiapine is neither an inhibitor nor an
inducer of any CYP enzyme system.
 Valporic acid increased quetiapine plasma
levels by clinically insignificant amount.

13.  CVS: postural hypotension, likely due to
quetiapine high affinity for adrenergic Alfa 1
receptors, is the most common
cardiovascular effects.
 RESPIRATORY & ENT SYSTEM: Dyspnea,
cough , pharyngitis, rhinitis & nasal
congestion

14.  GI system- dry mouth, constipation,
dyspepsia are commonly reported side
effects of quetiapine.
 HEMATOLOGICAL & LYMPHATIC System-
leukopenia & neutropenia in conjunction with
quetiapine therapy have been observed, vary
rare case of agranulocytosis, including fatal
causes have also been observed.

15.  CNS- Sedation, somnolence, dizziness are
frequently reported affects with lethargy
slightly less no.
 METABOLIC & NUTRITIONAL system :
peripheral edema has been described with
quetiapine & other antipsychotics.
Hyperlipidemia,hypertriglycerdemia &
hyperglycemia are common effects of
quetiapine.

16.  Signs and symptoms of overdose :
 Lethargy, tachycardia
 QT prolongation
 Respiratory distress
 Depression, hypotension
 Sedation
 Slurring of speech
 Overdose is not common
 No specific antidote
 Only symptomatic treatment needed