Quetiapine fumarate

Brand names: Seroquel

Why is Quetiapine fumarate prescribed?

Seroquel is prescribed for the treatment of schizophrenia, a mental disorder marked by delusions (false beliefs), hallucinations, disrupted thinking, and loss of contact with reality. It is also used for the treatment of manic and depressive episodes associated with bipolar disorder.

Seroquel belongs to one of the newer classes of antipsychotic medications. Researchers believe that it works by diminishing the action of dopamine and serotonin, two of the brain's chief chemical messengers.

Most important fact about Quetiapine fumarate

Seroquel may cause tardive dyskinesia, a condition characterized by uncontrollable muscle spasms and twitches in the face and body. This problem can be permanent, and appears to be most common among older adults, especially women.

Seroquel is not approved for use in elderly patients with dementia (including Alzheimer's disease) due to the increased risk of sudden death, heart failure, and pneumonia.

Antidepressants can increase the risk of suicidal thinking and behavior in children and teenagers. Both adult and pediatric patients taking antidepressants should be watched closely for changes in moods or actions, especially when they first start therapy or when their dose is increased or decreased. Patients and their families should contact the doctor immediately if new symptoms develop or seem to get worse. Signs to watch for include anxiety, hostility, insomnia, restlessness, impulsive or dangerous behavior, and thoughts about suicide or dying. Seroquel is not approved for use in pediatric patients.

How should you take Quetiapine fumarate?

Your doctor will increase your dose gradually until the drug takes effect. If you stop Seroquel for more than 1 week, you'll need to build up to your ideal dosage once again.

  • If you miss a dose...Take it as soon as you remember. If it is almost time for the next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at once.
  • Storage instructions...Store at room temperature.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Seroquel.

  • Side effects may include:Abdominal pain, constipation, diminished movement, dizziness, drowsiness, dry mouth, excessive muscle tone, headache, indigestion, low blood pressure (especially upon standing), nasal inflammation, neck rigidity, rapid or irregular heartbeat, rash, sleepiness, tremor, uncontrollable movements, weakness

Why should Quetiapine fumarate not be prescribed?

If Seroquel gives you an allergic reaction, you will not be able to use Quetiapine fumarate.

Special warnings about Quetiapine fumarate

Call your doctor immediately if you develop muscle stiffness, confusion, irregular or rapid heartbeat, excessive sweating, and high fever. These are signs of Neuroleptic Malignant Syndrome (NMS), a serious—and potentially fatal—reaction to the drug. Be especially wary if you have a history of heart attack, heart disease, heart failure, circulation problems, or irregular heartbeat.

Particularly during the first few days of therapy, Seroquel can cause low blood pressure, with accompanying dizziness, fainting, and rapid heartbeat. To minimize these effects, your doctor will increase your dose gradually. If you are prone to low blood pressure, take blood pressure medication, or become dehydrated, use Seroquel with caution.

Seroquel also tends to cause drowsiness, especially at the start of therapy, and can impair your judgment, thinking, and motor skills. Until you are certain of the drug's effect, use caution when operating machinery or driving a car.

Certain antipsychotic drugs, including Seroquel, are associated with an increased risk of developing high blood sugar, which on rare occasions has led to coma or death. See your doctor right away if you develop signs of high blood sugar, including dry mouth, unusual thirst, increased urination, and tiredness. If you have diabetes or have a high risk of developing it, see your doctor regularly for blood sugar testing.

People at high risk of suicide attempts should be prescribed the lowest dose possible to reduce the risk of intentional overdose.

Animal studies suggest that Seroquel may increase the risk of breast cancer, although human studies have not confirmed such a risk. If you have a history of breast cancer, see your doctor regularly for checkups.

If you are having problems with your vision, tell your doctor. There is a chance that Seroquel may cause cataracts, and you may be asked to see an eye doctor when you start Seroquel therapy, and every 6 months thereafter.

Seroquel poses a very slight risk of seizures, especially if you are over 65, have epilepsy, or have a condition that increases the risk of seizures. The drug can also suppress an underactive thyroid, and generally causes a minor increase in cholesterol levels. There is also a remote chance that it will trigger a prolonged and painful erection.

Other antipsychotic medications have been known to interfere with the body's temperature-regulating mechanism, causing patients to overheat. Although this problem has not occurred with Seroquel, caution is still advisable. Avoid exposure to extreme heat, strenuous exercise, and dehydration.

Seroquel is prescribed for the short-term treatment of rapid-onset bipolar mania; it is not approved for preventing future episodes. The effectiveness of the drug for treating mania for more than 3 weeks has not been studied.

The safety and effectiveness of Seroquel have not been studied in children.

Possible food and drug interactions when taking Quetiapine fumarate

Seroquel increases the effects of alcohol. Avoid alcoholic beverages while on Seroquel therapy.

If Seroquel is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Seroquel with the following:

Barbiturates such as phenobarbitalCarbamazepineCimetidineErythromycinFluconazoleItraconazoleKetoconazoleLevodopaLorazepamPhenytoinRifampinSteroid medications such as hydrocortisone and prednisoneThioridazine

Special information if you are pregnant or breastfeeding

The possibility of harm to a developing baby has not been ruled out. You should take Seroquel during pregnancy only if the benefits outweigh this potential risk. Notify your doctor as soon as you become pregnant or decide to become pregnant.

It is not known whether Seroquel appears in breast milk, and breastfeeding is not recommended.

Recommended dosage for Quetiapine fumarate

SCHIZOPHRENIA

Adults

The usual dosage range is 300 to 400 milligrams a day, divided into two or three smaller doses. Doses as low as 150 milligrams a day sometimes prove effective, and the dose rarely exceeds 750 milligrams per day. Doses above 800 milligrams per day have not been tested for safety. The dose is gradually increased over 4 days until the most effective dose is reached, using the following schedule: Day 1: Take 25 milligrams twice a day. Days 2, 3, and 4: The doctor will increase each daily dose by 25 to 50 milligrams, taken either two or three times a day. Day 5 and up: If needed, the doctor may increase each dose by 25 to 50 milligrams every 2 or more days.

BIPOLAR MANIA (SHORT-TERM TREATMENT OF ACUTE EPISODES)

Adults

The usual dosage range is 400 to 800 milligrams a day. Doses above 800 milligrams a day have not been tested for safety. The dosage will be gradually increased over 4 to 6 days until the most effective dose is reached, using the following schedule: Day 1: Take 50 milligrams twice a day. Day 2: The doctor will increase the dose to 100 milligrams twice a day. Day 3: The doctor will increase the dose to 150 milligrams twice a day. Day 4: The doctor will increase the dose to 200 milligrams twice a day. Days 5 and 6: If needed, the doctor may increase each dose by no more than 200-milligram increments to a total daily dose of 800 milligrams.

BIPOLAR DEPRESSION

Adults

The usual dose is 300 milligrams once a day at bedtime. The dosage will be gradually increased over 4 days using the following schedule: Day 1: Take 50 milligrams at bedtime. Day 2: The doctor will increase the dose to 100 milligrams at bedtime. Day 3: The doctor will increase the dose to 200 milligrams at bedtime. Day 4: The doctor will increase the dose to 300 milligrams at bedtime.

DOSAGE ADJUSTMENT

If you have liver problems, you may be started at 25 milligrams a day. The doctor will increase the dose as needed in increments of 25 to 50 milligrams a day based on your body's response.

The dosage may also need to be lowered if you are weak, elderly, or prone to low blood pressure reactions. You may also need your dose adjusted if you're taking certain drugs, including Dilantin, Tegretol, and phenobarbital.

Overdosage

Any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical help immediately.

  • Symptoms of Seroquel overdose may include:Dizziness, drowsiness, fainting, rapid heartbeat