Indications and Usage
Loxapine Capsules, USP are indicated for the treatment of schizophrenia. The efficacy of loxapine in schizophrenia was established in clinical studies which enrolled newly hospitalized and chronically hospitalized acutely ill schizophrenic patients as subjects.
Dosage and Administration
Loxapine Capsules, USP are administered, usually in divided doses, two to four times a day. Daily dosage (in terms of base equivalents) should be adjusted to the individual patient's needs as assessed by the severity of symptoms and previous history of response to antipsychotic drugs.
Oral Administration
Initial dosage of 10 mg twice daily is recommended, although in severely disturbed patients initial dosage up to a total of 50 mg daily may be desirable. Dosage should then be increased fairly rapidly over the first seven to ten days until there is effective control of symptoms of schizophrenia. The usual therapeutic and maintenance range is 60 mg to 100 mg daily. However, as with other drugs used to treat schizophrenia, some patients respond to lower dosage and others require higher dosage for optimal benefit. Daily dosage higher than 250 mg is not recommended.
Maintenance Therapy
For maintenance therapy, dosage should be reduced to the lowest level compatible with symptom control; many patients have been maintained satisfactorily at dosages in the range of 20 to 60 mg daily.
Contraindications
Loxapine is contraindicated in comatose or severe drug-induced depressed states (alcohol, barbiturates, narcotics, etc.).
Loxapine is contraindicated in individuals with known hypersensitivity to dibenzoxazepines.
Adverse Reactions
CNS Effects:Manifestations of adverse effects on the central nervous system, other than extrapyramidal effects, have been seen infrequently. Drowsiness, usually mild, may occur at the beginning of therapy or when dosage is increased. It usually subsides with continued loxapine therapy. The incidence of sedation has been less than that of certain aliphatic phenothiazines and slightly more than the piperazine phenothiazines. Dizziness, faintness, staggering gait, shuffling gait, muscle twitching, weakness, insomnia, agitation, tension, seizures, akinesia, slurred speech, numbness, and confusional states have been reported. Neuroleptic malignant syndrome (NMS) has been reported (see WARNINGS ).
Extrapyramidal Symptoms - Neuromuscular (extrapyramidal) reactions during the administration of loxapine have been reported frequently, often during the first few days of treatment. In most patients, these reactions involved parkinsonian-like symptoms such as tremor, rigidity, excessive salivation, and masked facies. Akathisia (motor restlessness) also has been reported relatively frequently. These symptoms are usually not severe and can be controlled by reduction of loxapine dosage or by administration of antiparkinson drugs in usual dosage.
Dystonia - Class effect: Symptoms of dystonia, prolonged abnormal contractions of muscle groups, may occur in susceptible individuals during the first few days of treatment. Dystonic symptoms include: spasm of the neck muscles, sometimes progressing to tightness of the throat, swallowing difficulty, difficulty breathing, and/or protrusion of the tongue. While these symptoms can occur at low doses, they occur more frequently and with greater severity with high potency and at higher doses of first generation antipsychotic drugs. An elevated risk of acute dystonia is observed in males and younger age groups.
Persistent Tardive Dyskinesia - As with all antipsychotic agents, tardive dyskinesia may appear in some patients on long-term therapy or may appear after drug therapy has been discontinued. The risk appears to be greater in elderly patients on high-dose therapy, especially females. The symptoms are persistent and in some patients appear to be irreversible. The syndrome is characterized by rhythmical involuntary movement of the tongue, face, mouth or jaw (e.g., protrusion of tongue, puffing of cheeks, puckering of mouth, chewing movements). Sometimes these may be accompanied by involuntary movements of extremities.
There is no known effective treatment for tardive dyskinesia; antiparkinson agents usually do not alleviate the symptoms of this syndrome. It is suggested that all antipsychotic agents be discontinued if these symptoms appear. Should it be necessary to reinstitute treatment, or increase the dosage of the agent, or switch to a different antipsychotic agent, the syndrome may be masked. It has been suggested that fine vermicular movements of the tongue may be an early sign of the syndrome, and if the medication is stopped at that time the syndrome may not develop.
Cardiovascular Effects:Tachycardia, hypotension, hypertension, orthostatic hypotension, lightheadedness, and syncope have been reported.
A few cases of ECG changes similar to those seen with phenothiazines have been reported. It is not known whether these were related to loxapine administration.
Hematologic:Rarely, agranulocytosis, thrombocytopenia, leukopenia.
Skin:Dermatitis, edema (puffiness of face), pruritus, rash, alopecia, and seborrhea have been reported with loxapine.
Anticholinergic Effects:Dry mouth, nasal congestion, constipation, blurred vision, urinary retention, and paralytic ileus have occurred.
Gastrointestinal:Nausea and vomiting have been reported in some patients. Hepatocellular injury (i.e., SGOT/SGPT elevation) has been reported in association with loxapine administration and rarely, jaundice and/or hepatitis questionably related to loxapine treatment.
Other Adverse Reactions:Weight gain, weight loss, dyspnea, ptosis, hyperpyrexia, flushed facies, headache, paresthesia, and polydipsia have been reported in some patients. Rarely, galactorrhea, amenorrhea, gynecomastia, and menstrual irregularity of uncertain etiology have been reported.
Drug Interactions
There have been rare reports of significant respiratory depression, stupor and/or hypotension with the concomitant use of loxapine and lorazepam.
The risk of using loxapine in combination with CNS-active drugs has not been systematically evaluated. Therefore, caution is advised if the concomitant administration of loxapine and CNS-active drugs is required.
Overdosage
Signs and symptoms of overdosage will depend on the amount ingested and individual patient tolerance. As would be expected from the pharmacologic actions of the drug, the clinical findings may range from mild depression of the CNS and cardiovascular systems to profound hypotension, respiratory depression, and unconsciousness. The possibility of occurrence of extrapyramidal symptoms and/or convulsive seizures should be kept in mind. Renal failure following loxapine overdosage has also been reported.
The treatment of overdosage is essentially symptomatic and supportive. Early gastric lavage and extended dialysis might be expected to be beneficial. Centrally-acting emetics may have little effect because of the antiemetic action of loxapine. In addition, emesis should be avoided because of the possibility of aspiration of vomitus. Avoid analeptics, such as pentylenetetrazol, which may cause convulsions. Severe hypotension might be expected to respond to the administration of norepinephrine or phenylephrine. EPINEPHRINE SHOULD NOT BE USED SINCE ITS USE IN A PATIENT WITH PARTIAL ADRENERGIC BLOCKADE MAY FURTHER LOWER THE BLOOD PRESSURE.Severe extrapyramidal reactions should be treated with anticholinergic antiparkinson agents or diphenhydramine hydrochloride, and anticonvulsant therapy should be initiated as indicated. Additional measures include oxygen and intravenous fluids.
Description
Loxapine, a dibenzoxazepine compound, represents a subclass of tricyclic antipsychotic agents, chemically distinct from the thioxanthenes, butyrophenones, and phenothiazines. Chemically, it is 2-Chloro-11-(4-methyl-1-piperazinyl)dibenz[ b,f][1,4]oxazepine. It is present as the succinate salt.
Each capsule for oral administration, contains loxapine succinate, USP 6.8, 13.6, 34.0 or 68.1 mg equivalent to 5, 10, 25 or 50 mg of loxapine base respectively. It also contains the following inactive ingredients: anhydrous lactose, colloidal silicon dioxide, gelatin, magnesium stearate, polacrilin potassium, sodium lauryl sulfate, talc, titanium dioxide, D&C Yellow #10 and FD&C Blue #1. Additionally, the 5 mg capsule contains D&C Red #33, the 10 mg capsule contains D&C Red #33 and D&C Red #28, and the 25 mg capsule contains FD&C Yellow #6.
In addition, the black imprinting ink contains shellac glace in ethanol, iron oxide black, n-butyl alcohol, propylene glycol, FD&C Blue #2/indigo carmine aluminum lake, FD&C Red #40/Allurea Red AC aluminum lake, FD&C Blue #1/brilliant Blue FCF aluminum lake, D&C Yellow #10 aluminum lake, SDA 3A alcohol, and methanol. The white imprinting ink contains pharmaceutical glaze in SD-45, titanium dioxide, isopropyl alcohol, ammonium hydroxide, propylene glycol, n-butyl alcohol and simethicone.
Clinical Pharmacology
Pharmacodynamics
Pharmacologically, loxapine is an antipsychotic for which the exact mode of action has not been established. However, changes in the level of excitability of subcortical inhibitory areas have been observed in several animal species in association with such manifestations of tranquilization as calming effects and suppression of aggressive behavior.
In normal human volunteers, signs of sedation were seen within 20 to 30 minutes after administration, were most pronounced within one and one-half to three hours, and lasted through 12 hours. Similar timing of primary pharmacologic effects was seen in animals.
Absorption, Distribution, Metabolism, and Excretion
Absorption of loxapine following oral or parenteral administration is virtually complete. The drug is removed rapidly from the plasma and distributed in tissues. Animal studies suggest an initial preferential distribution in lungs, brain, spleen, heart, and kidney. Loxapine is metabolized extensively and is excreted mainly in the first 24 hours. Metabolites are excreted in the urine in the form of conjugates and in the feces unconjugated.
How Supplied / Storage and Handling
Loxapine Capsules, USP are available in the following strengths:
Loxapine Succinate, USP 6.8 mg equivalent to 5 mg loxapine, opaque, with a dark green body and cap, imprinted with logo "LANNETT" on the cap and "1394" on the body are supplied as follows:
NDC 0527-1394-01 –Bottle of 100s
NDC 0527-1394-10 –Bottle of 1000s
Loxapine Succinate, USP 13.6 mg equivalent to 10 mg loxapine, yellow opaque body and dark green opaque cap, imprinted with logo "LANNETT" on the cap and "1395" on the body are supplied as follows:
NDC 0527-1395-01 –Bottle of 100s
NDC 0527-1395-10 –Bottle of 1000s
Loxapine Succinate, USP 34.0 mg equivalent to 25 mg loxapine, light green opaque body and dark green opaque cap, imprinted with logo "LANNETT" on the cap and "1396" on the body are supplied as follows:
NDC 0527-1396-01 –Bottle of 100s
NDC 0527-1396-10 –Bottle of 1000s
Loxapine Succinate, USP 68.1 mg equivalent to 50 mg loxapine, light blue opaque body and dark green opaque cap, imprinted with logo "LANNETT" on the cap and "1397" on the body are supplied as follows:
NDC 0527-1397-01 –Bottle of 100s
NDC 0527-1397-10 –Bottle of 1000s
Store at 20°-25°C (68°-77°F). [See USP controlled room temperature.] Dispense in a tight, child-resistant container.
Distributed by:
Lannett Company, Inc.
Philadelphia, PA 19136
CIB70541F
Rev. 11/24
Patient Counseling Information
Given the likelihood that some patients exposed chronically to antipsychotics will develop tardive dyskinesia, it is advised that all patients in whom chronic use is contemplated be given, if possible, full information about this risk. The decision to inform patients and/or their guardians must obviously take into account the clinical circumstances and the competency of the patient to understand the information provided.