Common Use

Seroquel is an oral antipsychotic medication prescribed for treating schizophrenia and acute manic episodes linked to bipolar I disorder. It has a higher affinity for serotonin receptors (5-HT2) compared to dopamine receptors (D1 and D2) in the brain. Additionally, it interacts with the alpha 1 adrenoreceptor and less so with the alpha 2 adrenoreceptor. Its binding duration with 5-HT2-serotonin and D2 dopamine receptors is under 12 hours. While the exact mechanism of Quetiapine is unknown, its therapeutic effects are believed to result from a combination of dopamine type 2 (D2) and serotonin type 2 (5HT2) receptor antagonism. This medication is effective for both acute and chronic psychosis, particularly in schizophrenia patients.

Dosage and Direction

Seroquel should be taken twice or thrice daily, with or without food, accompanied by a full glass of water. Extended-release tablets must be swallowed whole and not crushed or chewed. The initial four-day dosage schedule is as follows: 50 mg (first day), 100 mg (second day), 200 mg (third day), and 300 mg (fourth day). From the fourth day onward, the dosage should be adjusted to an effective level, which may reach up to 750 mg daily. For patients with liver or kidney failure, the starting dose is 25 mg/day, gradually increased by 25-50 mg until the effective dose is achieved. Always follow your doctor's instructions and avoid exceeding the recommended dose.

Precautions

Seroquel may impair concentration, affecting your ability to drive or operate machinery. Inform your doctor if you have a history of liver or kidney disease, heart disease, high blood pressure, heart rhythm issues, heart attack, stroke, low white blood cell counts, thyroid disorders, high cholesterol or triglycerides, diabetes, or trouble swallowing, as dosage adjustments or special safety tests may be required.

Contraindications

Seroquel is contraindicated in cases of hypersensitivity, pregnancy, and breastfeeding. It should be used cautiously in patients with hypotension, epilepsy, or a history of seizures. In older adults with dementia-related conditions, Seroquel may increase the risk of heart failure, pneumonia, sudden death, and other complications.

Possible Side Effects

Seroquel's antagonism of adrenergic a1 receptors can lead to orthostatic hypotension. Common side effects include headache, agitation, dizziness, drowsiness, weight gain, and stomach upset. Long-term use may cause irreversible tardive dyskinesia, characterized by involuntary movements of the jaw, lips, and tongue. Other nervous system-related effects include anxiety, fatigue, hostility, insomnia, tremors, convulsions, depression, and neuroleptic malignant syndrome. Cardiovascular side effects include tachycardia and QT interval prolongation. Additional side effects may include dry mouth, nausea, vomiting, abdominal pain, diarrhea, constipation, elevated liver enzymes, pharyngitis, rhinitis, skin rash, and eosinophilia.

Drug Interaction

Seroquel's absorption in the intestines is reduced by phenytoin (Dilantin) and thioridazine (Mellaril). It interacts with narcotic pain relievers, hypertension medications, and other substances, including oxycodone, acetaminophen, barbiturates, alprazolam, clonazepam, ethanol, prazosin, and terazosin. Its toxicity may increase when co-administered with drugs that affect cytochrome P450 enzymes, such as ketoconazole, itraconazole, fluconazole, erythromycin, clarithromycin, nefazodone, verapamil, and diltiazem.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is nearly time for your next dose, skip the missed one and resume your regular schedule. Do not double the dose to compensate for the missed one.

Overdose

An overdose of Seroquel may cause extreme drowsiness, rapid heart rate, light-headedness, or fainting. Seek immediate medical attention if you suspect an overdose.

Storage

Store Seroquel at room temperature, between 15-30°C (59-86°F), away from sunlight, moisture, children, and pets.

Disclaimer

This information provides a general overview of Seroquel and does not cover all directions, drug interactions, or precautions. It should not be used for self-treatment or self-diagnosis. Always consult your healthcare provider for specific instructions tailored to your condition. We disclaim any responsibility for the accuracy of this information or any consequences of its use.