| | Medication Information:
Clozapine (generic) ~ Clozaril (brand) Classification: Atypical antipsychotic
Common Usage: Clozapine is indicated for treatment-resistant psychosis
and for suicidal behavior in patients with schizophrenia or schizoaffective
disorder who are at chronic risk. CommonDosages: The usual starting dose of clozapine is one-half of a 25-mg
tablet (12.5) mg) given at bedtime and then twice daily, and then dosage
increases of 25 to 50 mg daily. Depending on the side effects, the
clozapine dose is typically about 300 mg daily at the end of two weeks.
Slow titration avoids several problems such as low blood pressure, seizures,
excessive sedation and an unnecessarily high dose. Based upon response and
adverse effects, the dosage should be increased every two to four weeks by 25 to
50 mg per day. The maximum dose is 900 mg per day. To avoid
seizures, the dose should never be increased by more than 100 mg per day.
Clinical response may require three months to become evident, and is known to
increase for at least two years in some patients. Important Side Effects:
Due to potentially dangerous side effects, clozapine should only be used in
people with psychosis that does not respond to adequate trials of two or three
other antipsychotics. It is not uncommon for people taking clozapine to
experience drowsiness or sedation, dizziness, headache, tremor, fainting, fast
heartbeat, low blood pressure, excessive salivation, sweating, dry mouth and
fever. Agranulocytosis:
The most dangerous potential side effect of clozapine is agranulocytosis, a
potentially life-threatening blood disorder in which the white blood cells,
needed to fight infections, are decreased. Agranulocytosis occurs in
approximately 1.3 percent of people who take clozapine every year. Most
often this happens between six and 12 weeks after starting clozapine, but
agranulocytosis has appeared after two years. For this reason , anyone
taking clozapine needs to have a blood test weekly for the first six months of
treatment, and then every other week indefinitely. If an abnormal blood
event is detected, weekly blood tests will be needed for an additional six
months. Only a one- or two-week supply of medication will be provided,
enough to last until the next blood text. If a patient has had
agranulocytosis or another blood disorder while on clozapine, they must stop
clozapine and not restart is. Blood tests will be needed for four weeks
after the last dose of clozapine is taken. Seizures: Seizures
have also been associated with clozapine, especially at higher doses; clozapine
should be used with caution in patients with a history of seizure. Myocarditis:
Clozapine may also be associated with myocarditis (inflammation of the muscle
walls of the heart) and should be discontinued immediately if myocarditis is
suspected. Other cardiovascular and respiratory effects, including
orthostatic hypotension, have been found in patients. The most serious
cardiovascular and respiratory effects have been in patients also taking
benzodiazepines or other psychotropic drugs. Caution should be taken when
administering clozapine with benzodiazepines or other psychotropic drugs. Other: Some of the
other possible side effects of clozapine include abdominal discomfort or
heartburn; akathisia (internal sense of the need to move); blurred near vision;
chest pain; chills; confusion; constipation; decreased sexual ability;
difficulty breathing; difficulty urinating; high blood pressure; increase blood
sugar; increased sweating; increased watering mouth or drooling; insomnia; liver
problems (dark urine, decreased appetite, nausea, vomiting, yellow eyes, or
skin); loss of bladder control; mental depression; nausea or vomiting; low blood
pressure when standing up quickly; sore throat; sores, ulcers or white spots on
lips or in mouth; swelling or pain in leg; trembling or shaking; unusual
anxiety, nervousness, or irritability; unusual bleeding or bruising; unusual
tiredness or weakness; unusually pale skin; weight gain. As with any
dopamine blocking agent, there is a risk of tardive dyskinesia, the development
of abnormal movements that may not go away when the medication is discontinued,
but this risk is smaller with clozapine than with other typical antipsychotic
drugs. This is not a complete
list of all known or potential adverse effects. Notify your prescriber or
pharmacist of any symptoms that have started since you began taking this
medication, changing its dose, or adding or changing other medication or diet.
Take care when performing any tasks (for example, driving or operating
machinery) that requires your attention until you have experience with this drug
and are confident you can perform the tasks safely. Interactions with Other Medications: Clozapine should not be taken with
other drugs that can cause low white blood cell counts, such as carbamazepine
(Tegretol). Because it has primary effects on the central nervous system
(CNS), clozapine should be taken carefully with other psychotropic medications.
Taking warfarin (Coumadin) or digoxin (Lanoxin) with clozapine may cause an
increase in blood concentrations of those drugs. Cimetidine (Tagamet),
erythromycin (E-Mycin) and fluvoxamine (Lubox) may increase blood levels of
clozapine. Clozapine may interact with anticholinergics, bone marrow
depressants, fluvoxamine, hypotension-producing medications, and lithium. This is not a complete
list of all known or potential drug interactions. To help prevent
problems, always make sure that your pharmacist and all prescribers know about
all medications you are taking, including over-the-counter drugs; dietary herbal
supplements; folk or home remedies; or unusual foods, drinks, or dietary habits. Identification: Clozapine is available as Clozaril in 25- and 100-mg
pale-yellow tablets. Clozapine is also available in a variety of generic
formulations. Storage: Store this medication at normal room temperature (59° F to 86°
F) in a tightly closed, light- and moisture-resistant container. If you have
difficulty opening child-resistant containers, your pharmacist can provide a
container that is easier to open. Keep the medication out of direct sunlight
and avoid storing it in a warm or humid area - such as the bathroom or kitchen -
to prevent deterioration. To prevent accidental poisoning, keep all mediations
out of the reach of children. Do not take an expired medication. Do not
transfer medication from one container to another. Carefully discard
discontinued medication where children cannot find it. Edited by Lawrence H.
Price, M.D. ASERVICE OF…. The Brown University Psychopharmacology Update
Note: These guidelines are for general information only.For more specific information, consult your physician orpharmacist. |
