Q-Pin

Q-Pin

quetiapine

Manufacturer:

Amarox
Full Prescribing Info
Contents
Quetiapine.
Description
Q-PIN Film coated tablet 25 mg, each film coated tablet contains: Quetiapine Fumarate equivalent to Quetiapine 25 mg.
Q-PIN Film coated tablet 100 mg, each film coated tablet contains: Quetiapine Fumarate equivalent to Quetiapine 100 mg.
Q-PIN Film coated tablet 200 mg, each film coated tablet contains: Quetiapine Fumarate equivalent to Quetiapine 200 mg.
Q-PIN Film coated tablet 300 mg, each film coated tablet contains: Quetiapine Fumarate equivalent to Quetiapine 300 mg.
Action
Pharmacology: Mechanism action: Quetiapine is an atypical antipsychotic agent. Quetiapine and the active human plasma metabolite, Norquetiapine interact with a broad range of neurotransmitter receptors. Quetiapine and Norquetiapine exhibits affinity for brain serotonin (5HT2) and dopamine D1 and D2 receptors. It is this combination of receptor antagonism with a higher selectivity for 5HT2 relative to dopamine D2 receptors which is believed to contribute to the antipsychotic properties and low extrapyramidal side effect (EPS) liability of Quetiapine compared to typical antispychotics. Quetiapine has no affinity for the Norepinephrine transporter (NET) and low affinity for the serotonin 5HT1A receptor, whereas Norquetiapine has high affinity for both. Inhibition of NET and partial agonist action at 5HT1A sites by Norquetiapine may contribute to Quetiapine's therapeutic efficacy as an antidepressant. Quetiapine and Norquetiapine have high affinity at histaminergic and adrenergic alpha1 receptors and moderate affinity at adrenergic alpha2 receptors. Quetiapine also has low or no affinity for muscarinic receptors, while Norquetiapine has moderate to high affinity for several muscarinic receptor subtypes, which may explain anti-cholinergic (muscarinic) effects.
Pharmacodynamics: Quetiapine is active in tests for antipsychotic activity, such as conditioned avoidance. It also blocks the action of dopamine agonists, measured either behaviourally or electrophysiologically, and elevates dopamine metabolite concentrations, a neurochemical index of dopamine D2 receptor blockade.
The extent to which the Norquetiapine metabolite contributes to the pharmacological activity of Quetiapine in humans is not known.
Pharmacokinetics: This study was designed as a randomized, single blind, two period, single dose, cross-over study with one week washout period in 26 healthy subjects under fasting condition. The study was conducted following an oral administration of one tablet 25 mg of the test drug or one tablet 25 mg of the reference drug.
Based on the pharmacokinetic parameters of Quetiapine (N = 26), mean ± SD for Test Drug and Reference Drug showed: Cmax values were 98.89 (40.67) and 92.19 (39.24) ng.mL-1, respectively; AUCt values were 358.76 (151.38) and 362.66 (155.63) h.ng.mL-1, respectively; AUCinf values were 369.53 (156.42) and 374.79 (163.36) h.ng.mL-1, respectively; Tmax values were 0.75 (0.33 - 2.00) and 0.75 (0.50 - 1.50) hours, respectively; T1/2 values were 3.90 (1.27) and 4.18 (1.54) hours, respectively.
Results from bioequivalence study for Test Drug and Reference Drug were as following: 90.00% Confidence Intervals of geometric means ratio of the two bioavailability parameters of Quetiapine were 98.71 - 117.86% for Cmax and 94.37 - 103.75% for AUCt. Intra subject CV (%) of Cmax and AUCt for Quetiapine were 18.63 and 9.85%, respectively.
Conclusion: These results showed that 25 mg Quetiapine film coated tablet was bioequivalent to the reference product.
Special populations: Gender: The kinetics of Quetiapine do not differ between men and women.
Elderly: The mean clearance of Quetiapine in the elderly is lower than that seen in adults aged 18 to 65 years.
Renal impairment: The mean plasma clearance of Quetiapine was reduced in subjects with severe renal impairment, but the individual clearance values are within the range for normal subjects.
Hepatic impairment: As Quetiapine is extensively metabolised by the liver, elevated plasma levels are expected in the population with hepatic impairment. Dose adjustments may be necessary in these patients (see DOSAGE & ADMINISTRATION).
Indications/Uses
Treatment of schizophrenia.
Treatment of manic episodes associated with bipolar disorder.
Treatment of depressive episodes associated with bipolar disorder.
Dosage/Direction for Use
Different dosing schedules exist for each indication. It must therefore be ensured that patients receive clear information on the appropriate dosage for their condition. Q-PIN can be administered with or without food.
Adults: For the treatment of schizophrenia: Q-PIN should be administered twice daily. The total daily dose for the first 4 days of therapy is 50 mg (Day 1), 100 mg (Day 2), 200 mg (Day 3) and 300 mg (Day 4).
From Day 4 onwards, the dose should be titrated to the usual effective dose range of 300 to 450 mg/day. Depending on the response and tolerability of the individual patient, the dose may be adjusted within the range 150 to 750 mg/day.
For the treatment of manic episodes associated with bipolar disorder: Q-PIN should be administered twice daily. As monotherapy or as adjunct therapy to mood stabilizers, the total daily dose for the first four days of therapy is 100 mg (Day 1), 200 mg (Day 2), 300 mg (Day 3) and 400 mg (Day 4). Further dosage adjustments up to 800 mg per day by Day 6 should be in increments of no greater than 200 mg per day.
The dose may be adjusted depending on response and tolerability of the individual patient, within the range of 200 to 800 mg per day. The usual effective dose is in the range of 400 to 800 mg per day.
For the treatment of depressive episodes associated with bipolar disorder: Q-PIN should be administered once daily at bedtime. Q-PIN should be titrated as follows: 50 mg (Day 1), 100 mg (Day 2), 200 mg (Day 3) and 300 mg (Day 4). Q-PIN can be titrated to 400 mg on Day 5 and up to 600 mg by Day 8. Antidepressant efficacy was demonstrated with Q-PIN at 300 mg and 600 mg; however no additional benefit was seen in the 600 mg group.
Elderly: As with other antipsychotics, Q-PIN should be used with caution in the elderly, especially during the initial dosing period. Elderly patients should be started on Q-PIN 25 mg/day. The dose should be increased daily, in increments of 25 to 50 mg, to an effective dose. The rate of dose titration of Q-PIN may need to be slower, and the daily therapeutic dose lower, than that used in younger patients, depending on the response and tolerability of the individual patient.
Efficacy and safety has not been evaluated in patients over 65 years with depressive episodes in the framework of bipolar disorder.
Children and adolescents: The safety and efficacy of Q-PIN have not been evaluated in children and adolescents.
Renal impairment: Dosage adjustment is not necessary in patients with renal impairment.
Hepatic impairment: Quetiapine is extensively metabolised by the liver. Therefore, Q-PIN should be used with caution in patients with known hepatic impairment, especially during the initial dosing period. Patients with known hepatic impairment should be started with 25 mg/day. The dosage should be increased daily with increments of 25 - 50 mg/day until an effective dosage, depending on the response and tolerability of the individual patient.
Overdosage
In general, reported signs and symptoms were those resulting from an exaggeration of the drug's known pharmacological effects, i.e., drowsiness and sedation, tachycardia, hypotension and anticholinergic effects.
Fatal outcome has been reported. However, survival has also been reported following acute overdoses of up 30 grams. There have been reports of overdose of Quetiapine alone resulting in death or coma. Additionally, the following events have been reported in the setting of monotherapy overdose with Quetiapine: QT-prolongation, seizures, status epilepticus, rhabdomyolysis, respiratory depression, urinary retention, confusion, delirium and/or agitation.
Patients with pre-existing severe cardiovascular disease may be at an increased risk of the effects of overdose (see PRECAUTIONS).
Management of overdose: There is no specific antidote to Quetiapine. In cases of severe signs, the possibility of multiple drug involvement should be considered, and intensive care procedures are recommended, including establishing and maintaining a patent airway, ensuring adequate oxygenation and ventilation, and monitoring and support of the cardiovascular system.
In this context, published reports in the setting of anti-cholinergic symptoms describe a reversal of severe CNS effects, including coma and delirium, with administration of intravenous Physostigmine (1 - 2 mg), under continuous ECG monitoring.
Whilst the prevention of absorption in overdose has not been investigated, gastric lavage can be indicated in severe poisonings and if possible to perform within one hour of ingestion. The administration of activated charcoal should be considered.
In cases of Quetiapine overdose, refractory hypotension should be treated with appropriate measures such as intravenous fluids and/or sympathomimetic agents. Epinephrine and Dopamine should be avoided, since beta stimulation may worsen hypotension in the setting of Quetiapine-induced alpha blockade.
Close medical supervision and monitoring should be continued until the patient recovers.
Contraindications
Hypersensitivity to the active substance or to any of the excipients of this product.
Concomitant administration of cytochrome P450 3A4 inhibitors, such as HIV-protease inhibitors, Azole-antifungal agents, Erythromycin, Clarithromycin and Nefazodone, is contraindicated.
Special Precautions
As Q-PIN has several indications, the safety profile should be considered with respect to the individual patient's diagnosis and the dose being administered.
Suicide/suicidal thoughts or clinical worsening: Depression in bipolar disorder is associated with an increased risk of suicidal thoughts, self-harm and suicide (suicide-related events). This risk persists until significant remission occurs. As improvement may not occur during the first few weeks or more of treatment, patients should be closely monitored until such improvement occurs. It is general experience that the risk of suicide may increase in the early stages of recovery.
In addition, physicians should consider the potential risk of suicide-related events after abrupt cessation of Quetiapine treatment, due to the known risk factors for the disease being treated.
Other psychiatric conditions for which Quetiapine is prescribed can also be associated with an increased risk of suicide related events. In addition, these conditions may be co-morbid with major depressive episodes. The same precautions observed when treating patients with major depressive episodes should therefore be observed when treating patients with other psychiatric disorders.
Patients with a history of suicide related events, or those exhibiting a significant degree of suicidal ideation prior to commencement of treatment are known to be at greater risk of suicidal thoughts or suicide attempts, and should receive careful monitoring during treatment.
Close supervision of patients and in particular those at high risk should accompany drug therapy especially in early treatment and following dose changes. Patients (and caregivers of patients) should be alerted about the need to monitor for any clinical worsening, suicidal behaviour or thoughts and unusual changes in behaviour and to seek medical advice immediately if these symptoms present.
Extrapyramidal symptoms: The use of Quetiapine has been associated with the development of akathisia, characterised by a subjectively unpleasant or distressing restlessness and need to move often accompanied by an inability to sit or stand still. This is most likely to occur within the first few weeks of treatment. In patients who develop these symptoms, increasing the dose may be detrimental.
Tardive dyskinesia: Tardive dyskinesia is a syndrome of potentially irreversible, involuntary, dyskinetic movements that may develop in patients treated with antipsychotic drugs including Quetiapine. If signs and symptoms of tardive dyskinesia appear, dose reduction or discontinuation of Quetiapine should be considered. The symptoms of tardive dyskinesia can worsen or even arise after discontinuation of treatment (see ADVERSE REACTIONS).
Somnolence and dizziness: Quetiapine treatment has been associated with somnolence and related symptoms, such as sedation (see ADVERSE REACTIONS). Bipolar depression patients experiencing somnolence of severe intensity may require more frequent contact for a minimum of 2 weeks from onset of somnolence, or until symptoms improve and treatment discontinuation may need to be considered.
Quetiapine treatment has been associated with orthostatic hypotension and related dizziness (see ADVERSE REACTIONS) which, like somnolence has onset usually during the initial dose-titration period. This could increase the occurrence of accidental injury (fall), especially in the elderly population. Therefore, patients should be advised to exercise caution until they are familiar with the potential effects of the medication.
Sleep apnoea syndrome: Sleep apnoea syndrome has been reported in patients using Quetiapine. In patients receiving concomitant central nervous system depressants and who have a history of or are at risk for sleep apnoea, such as those who are overweight/obese or are male, Quetiapine should be used with caution.
Anti-cholinergic (muscarinic) effects: Norquetiapine, an active metabolite of Quetiapine, has moderate to strong affinity for several muscarinic receptor subtypes. This contributes to ADRs reflecting anticholinergic effects when Quetiapine is used at recommended doses, when used concomitantly with other medications having anti-cholinergic effects, and in the setting of overdose. Quetiapine should be used with caution in patients receiving medications having anti-cholinergic (muscarinic) effects. Quetiapine should be used with caution in patients with a current diagnosis or prior history of urinary retention, significant prostatic hypertrophy, intestinal obstruction or related conditions, increased intraocular pressure or narrow angle glaucoma.
Cardiovascular: Quetiapine should be used with caution in patients with known cardiovascular disease, cerebrovascular disease, or other conditions predisposing to hypotension. Quetiapine may induce orthostatic hypotension especially during the initial dose-titration period and therefore, dose reduction or more gradual titration should be considered if this occurs. A slower titration regimen could be considered in patients with underlying cardiovascular disease.
Seizures: No data is available about the incidence of seizures in patients with a history of seizure disorder. As with other antipsychotics, caution is recommended when treating patients with a history of seizures (see ADVERSE REACTIONS).
Neuroleptic malignant syndrome: Neuroleptic malignant syndrome has been associated with antipsychotic treatment, including Quetiapine (see ADVERSE REACTIONS). Manifestations include hyperthermia, altered mental status, muscular rigidity, autonomic instability, and increased creatine phosphokinase. In such an event, Quetiapine should be discontinued and appropriate medical treatment given.
Neutropenia and agranulocytosis: Severe neutropenia (neutrophil count < 0.5 x 109/L) without infection has been reported. There have been reports of agranulocytosis (severe neutropenia with infection) among all patients treated with Quetiapine. Most of these cases of severe neutropenia have occurred within the first two months of starting therapy with Quetiapine. There was no apparent dose relationship. Resolution of leucopenia and/or neutropenia has followed cessation of therapy with Quetiapine. Possible risk factors for neutropenia include pre-existing low white cell count (WBC) and history of drug induced neutropenia.
There have been cases of agranulocytosis in patients without pre-existing risk factors. Neutropenia should be considered in patients presenting with infection, particularly in the absence of obvious predisposing factor(s), or in patients with unexplained fever, and should be managed appropriately.
Quetiapine should be discontinued in patients with a neutrophil count < 1.0 x 109/L. These patients should be observed for signs and symptoms of infection and neutrophil counts followed until they exceed 1.5 x 109/L).
Effects on ability to drive and use machines: Given its primary central nervous system effects, Quetiapine may interfere with activities requiring mental alertness. Therefore, patients should be advised not to drive or operate machinery, until individual susceptibility is known.
Use in pregnancy and lactation: The safety and efficacy of Quetiapine during human pregnancy have not yet been established. Following pregnancies in which Quetiapine was used, neonatal withdrawal symptoms were observed. Therefore, Quetiapine should only be used during pregnancy if the benefits justify the potential risks.
There have been published reports of Quetiapine excretion into human breast milk; however the degree of excretion was not consistent. Women who are breast-feeding should therefore be advised to avoid breast-feeding while taking Quetiapine.
Neonates exposed to antipsychotics (including Quetiapine) during the third trimester of pregnancy are at risk of adverse reactions including extrapyramidal and/or withdrawal symptoms that may vary in severity and duration following delivery. There have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, or feeding disorder. Consequently, newborns should be monitored carefully.
Use In Pregnancy & Lactation
The safety and efficacy of Quetiapine during human pregnancy have not yet been established. Following pregnancies in which Quetiapine was used, neonatal withdrawal symptoms were observed. Therefore, Quetiapine should only be used during pregnancy if the benefits justify the potential risks.
There have been published reports of Quetiapine excretion into human breast milk; however the degree of excretion was not consistent. Women who are breast-feeding should therefore be advised to avoid breast-feeding while taking Quetiapine.
Neonates exposed to antipsychotics (including Quetiapine) during the third trimester of pregnancy are at risk of adverse reactions including extrapyramidal and/or withdrawal symptoms that may vary in severity and duration following delivery. There have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, or feeding disorder. Consequently, newborns should be monitored carefully.
Adverse Reactions
The most reported Adverse Drug Reactions (ADRs) with Quetiapine are somnolence, dizziness, dry mouth, withdrawal (discontinuation) symptoms, elevations in serum triglyceride levels, elevation in total cholesterol (predominantly LDL cholesterol), decrease in HDL cholesterol, weight gain, decreased haemoglobin and extrapyramidal symptoms.
Blood and lymphatic system disorders: Very common: Decreased haemoglobin.
Common: Leucopenia, decreased neutrophil count, eosinophils increased.
Uncommon: Thrombocytopenia, anemia, platelet count decreased.
Rare: Agranulocytosis.
Unknown: Neutropenia.
Immune system disorders: Uncommon: Hypersensitivity (including allergic skin reactions).
Very rare: Anaphylactic reaction.
Endocrine disorders: Common: Hyperprolactinaemia, decreases in total T4, decreases in free T4, decreases in total T3, increases in TSH.
Uncommon: Decreases in free T3, hypothyroidism.
Very rare: Inappropriate antidiuretic hormone secretion.
Metabolism and nutritional disorders: Very common: Elevations in serum triglyceride levels, elevations in total cholesterol (predominantly LDL cholesterol), decreases in HDL cholesterol, weight gain.
Common: Increased appetite, blood glucose increased to hyperglycaemic levels.
Uncommon: Hyponatraemia, diabetes mellitus.
Rare: Metabolic syndrome.
Psychiatric disorders: Common: Abnormal dreams and nightmares, suicidal ideation and suicidal behaviour.
Rare: Somnambulism and related reactions such as sleep talking and sleep related eating disorder.
Nervous system disorders: Very common: Dizziness, somnolence, headache, extrapyramidal symptoms.
Common: Dysarthria.
Uncommon: Seizure, restless legs syndrome, tardive dyskinesia, syncope.
Cardiac disorders: Common: Tachycardia, palpitations.
Uncommon: QT prolongation, bradycardia.
Eye disorders: Common: Vision blurred.
Vascular disorders: Common: Orthostatic hypotension.
Rare: Venous thromboembolism.
Respiratory, thoracic and mediastinal disorder: Common: Dyspnoea.
Uncommon: Rhinitis.
Gastrointestinal disorders: Very common: Dry mouth.
Common: Constipation, dyspepsia, vomiting.
Uncommon: Dysphagia.
Rare: Pancreatitis, intestinal obstruction/ileus.
Hepato-biliary disorders: Common: Elevations in ALT, elevations in gamma-GT levels.
Uncommon: Elevations in AST.
Rare: Jaundice, hepatitis (with or without jaundice).
Skin and subcutaneous tissue disorders: Very rare: Angioedema, Stevens-Johnson syndrome.
Unknown: Toxic Epidermal Necrolysis, erythema multiforme.
Musculoskeletal and connective tissue disorders: Very rare: Rhabdomyolysis.
Pregnancy, puerperium and perinatal conditions: Unknown: Drug withdrawal syndrome neonatal.
Reproductive system and breast disorders: Uncommon: Sexual dysfunction.
Rare: Priapism, galactorrhoea, breast swelling, menstrual disorder.
General disorders and administration site conditions: Very common: Withdrawal (discontinuation) symptoms.
Common: Mild asthenia, peripheral oedema, irritability, pyrexia.
Rare: Neuroleptic malignant syndrome, hypothermia.
Renal and urinary disorders: Uncommon: Urinary retention.
Investigations: Rare: Elevations in blood creatine phosphokinase.
Cases of QT prolongation, ventricular arrhythmia, sudden unexplained death, cardiac arrest and torsades de pointes have been reported with the use of neuroleptics and rare considered class effects.
Drug Interactions
Concomitant use of Quetiapine with a strong hepatic enzyme inducer such as Carbamazepine or Phenytoin substantially decreases Quetiapine plasma concentrations, which could affect the efficacy of Quetiapine therapy. In patients receiving a hepatic enzyme inducer, initiation of Quetiapine treatment should only occur if the physician considers that the benefits of Quetiapine outweigh the risks of removing the hepatic enzyme inducer. It is important that any change in the inducer is gradual, and if required, replaced with a non-inducer (e.g. Sodium valproate).
Weight: Weight gain has been reported in patients who have been treated with Quetiapine, and should be monitored and managed appropriately as in accordance with utilized antipsychotic guidelines (see ADVERSE REACTIONS).
Hyperglycaemia: Hyperglycaemia and/or development or exacerbation of diabetes occasionally associated with ketoacidosis or coma has been reported, including some fatal cases (see ADVERSE REACTIONS). In some cases, a prior increase in body weight has been reported which may be a predisposing factor. Appropriate monitoring is advisable in accordance with utilised antipsychotic guidelines. Patients treated with any antipsychotic agent including Quetiapine, should be observed for signs and symptoms of hyperglycaemia, (such as polydipsia, polyuria, polyphagia and weakness) and patients with diabetes mellitus or with risk factors for diabetes mellitus should be monitored regularly for worsening of glucose control. Weight should be monitored regularly.
Lipids: Increases in triglycerides, LDL and total cholesterol, and decreases in HDL cholesterol have been observed with Quetiapine (see ADVERSE REACTIONS). Lipid changes should be managed appropriately.
Metabolic risk: Given the observed changes in weight, blood glucose (see hyperglycaemia as mentioned) and lipids, patients (including those with normal baseline value) may experience worsening of their metabolic risk profile, which should be managed appropriately (see ADVERSE REACTIONS).
QT Prolongation: As with other antipsychotics, caution should be exercised when Quetiapine is prescribed in patients with cardiovascular disease or family history of QT prolongation. Also caution should be exercised when Quetiapine is prescribed either with medicines known to increase QT interval or with concomitant neuroleptics, especially in the elderly, in patients with congenital long QT syndrome, congestive heart failure, heart hypertrophy, hypokalaemia or hypomagnesaemia.
Cardiomyopathy and myocarditis: Cardiomyopathy and myocarditis have been reported, however a causal relationship to Quetiapine has not been established. Treatment with Quetiapine should be reassessed in patients with suspected cardiomyopathy or myocarditis.
Withdrawl: Acute withdrawl symptoms such as insomnia, nausea, headache, diarrhoea, vomiting, dizziness, and irritability have been described after abrupt cessation of Quetiapine. Gradual withdrawal over a period of at least one to two weeks is advisable (see ADVERSE REACTIONS).
Misuse and abuse: Cases of misuse and abuse have been reported. Caution may be needed when prescribing Quetiapine to patients with a history of alcohol or drug abuse.
Elderly patients with dementia: Quetiapine is not approved for the treatment of dementia-related psychosis.
Dysphagia: Dysphagia (see ADVERSE REACTIONS) and aspiration have been reported with Quetiapine. Although a casual relationship with aspiration pneumonia has not been established, Quetiapine should be used with caution in patients at risk for aspiration pneumonia.
Venous thromboembolism (VTE): Cases of venous thromboembolism (VTE) have been reported with antipsychotic drugs. Since patients treated with antipsychotics often present with acquired risk factors for VTE, all possible risk factors for VTE should be identified before and during treatment with Quetiapine and preventive measures undertaken.
Constipation and intestinal obstruction: Constipation represents a risk factor for intestinal obstruction. Constipation and intestinal obstruction have been reported with Quetiapine (see ADVERSE REACTIONS). This includes fatal reports in patients who are at higher risk of intestinal obstruction, including those that are receiving multiple concomitant medications that decrease intestinal motility and/or may not report symptoms of constipation.
Pancreatitis: Pancreatitis has been reported, many patients had factors which are known to be associated with pancreatitis such as increased triglycerides (see PRECAUTIONS), gallstones, and alcohol consumption.
Concomitant illness: Quetiapine should be used with caution in patients with known cardiovascular disease, cerebrovascular disease, or other conditions predisposing to hypotension. Quetiapine may induce orthostatic hypotension especially during the initial dose-titration period. In patients who have a history of or are at risk for sleep apnoea, and are receiving concomitant central nervous system (CNS) depressants, Quetiapine should be used with caution.
Additional information: Quetiapine data in combination with Divalproex or Lithium in acute moderate to severe manic episodes is limited.
Lactose: Q-PIN Tablet contain lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency, or glucose-galactose malabsorption should not take this medicine.
Interaction with other medicinal products and other forms of interaction: Given the primary central nervous system effects of Quetiapine, Quetiapine should be used with caution in combination with other centrally acting medicinal products and alcohol.
Cytochrome P450 (CYP) 3A4 is the primary enzyme responsible for the cytochrome P450 mediated metabolism of Quetiapine.
Concomitant use of Quetiapine with CYP3A4 inhibitors is contraindicated. It is also not recommended to consume grapefruit juice while on Quetiapine therapy.
Co-administration of Carbamazepine (a known hepatic enzyme inducer) significantly increased the clearance of Quetiapine. As a consequence of this interaction, lower plasma concentrations can occur, which could affect the efficacy of Quetiapine therapy.
Co-administration of Quetiapine and Phenytoin (another microsomal enzyme inducer) caused a greatly increased clearance of Quetiapine. In patients receiving a hepatic enzyme inducer, initiation of Quetiapine treatment should only occur if the physician considers that the benefits of Quetiapine outweigh the risks of removing the hepatic enzyme inducer. It is important that any change in the inducer is gradual, and if required, replaced with a non-inducer (e.g. sodium valproate) (see PRECAUTIONS).
The pharmacokinetics of Quetiapine were not significantly altered by co-administration of the antidepressants Imipramine (a known CYP 2D6 inhibitor) or Fluoxetine (a known CYP 3A4 and CYP 2D6 inhibitor).
The pharmacokinetics of Quetiapine were not significantly altered by co-administration of the antipsychotics Risperidone or Haloperidol.
Concomitant use of Quetiapine and Thioridazine caused an increased clearance of Quetiapine.
The pharmacokinetics of Quetiapine were not altered following co-administration with Cimetidine.
The pharmacokinetics of Lithium were not altered when co-administered with Quetiapine.
The pharmacokinetics of Sodium valproate and Qetiapine were not altered to a relevant extent when co-administered. Children and adolescents who received Valproate, Quetiapine, or both, found a higher incidence of leucopenia and neutropenia in the combination group versus the monotherapy groups.
Caution should be exercised treating patients receiving other medications having anticholinergic (muscarinic) effects (see PRECAUTIONS).
Caution should be exercised when Quetiapine is used concomitantly with medicinal products known to cause electrolyte imbalance or to increase QT interval.
There have been reports of false positive results in enzyme immunoassays for Methadone and tricyclic antidepressants in patients who have taken Quetiapine. Confirmation of questionable immunoassay screening results by an appropriate chromatographic technique is recommended.
Storage
Store below 30°C.
MIMS Class
ATC Classification
N05AH04 - quetiapine ; Belongs to the class of diazepines, oxazepines and thiazepines antipsychotics.
Presentation/Packing
FC tab 25 mg x 6 x 10's. 100 mg x 6 x 10's. 200 mg x 6 x 10's. 300 mg x 6 x 10's.
Register or sign in to continue
Asia's one-stop resource for medical news, clinical reference and education
Sign up for free
Already a member? Sign in