Loxapine
Loxapine
Definition
Loxapine is a prescription-only drug used to treat serious mental, nervous, and emotional disorders. Loxapine is sold under the brand name Loxitane in the United States. Loxapine is also available in generic form.
Purpose
Loxapine is used to treat a variety of mental disorders including anxiety , mania, depression , and psychotic disorders.
Description
Loxapine is in the class of drugs known as anti-psychotic agents. The exact mode of action of loxapine has not been precisely determined, but this drug has a tranquilizing effect on patients with anxiety, mania, and other psychotic disorders. It is known that loxapine reduces the amount of dopamine transmitted within the brain. Loxapine is available in 5-, 10-, 25-, and 50-mg tablets.
Recommended dosage
Loxapine is available in oral solution, capsules, tablets, and injectable form. The typical starting dose for adults and children over the age of 16 years is 10 mg given two to four times daily. The maximum range after the initial period is between 60 mg and 100 mg given two to four times per day. After a period of time, the dose is usually lowered to 20-60 mg per day given in divided doses. Injections are usually given only during the initial phase and are delivered into muscle (IM) in doses ranging from 12.5 mg to 50 mg every four to six hours until a desired level of response is reached. Then, the patient is usually put on the oral (PO) form for maintenance therapy. Guidelines for use in people under the age of 16 years have not been established.
Precautions
People taking loxapine should not stop taking this medication suddenly. The dosage should be gradually decreased over time. Loxapine should not be combined with other agents that depress the central nervous system, such as antihistamines, alcohol, tranquilizers, sleeping medications, and seizure medications. Loxapine can cause the skin to become more sensitive to the sun. People taking this drug should use sunscreen with a skin protection factor (SPF) greater than 15.
Loxapine is typically not administered to people who are in severe drug-induced states or in a coma. People with a history of seizures , heart disease, prostate enlargement, glaucoma, or chronic obstructive pulmonary disorder should receive loxapine only after careful evaluation. Guidelines for use in children under the age of 16 years have not been established. Loxapine has not been thoroughly studied in pregnant and nursing women, but such women should exercise great caution when using loxapine.
Side effects
Rare side effects, but ones that need to be reported immediately to a doctor, include seizures, breathing
KEY TERMS
Anticholinergic —Related to the ability of a drug to block the nervous system chemical acetylcholine. When acetylcholine is blocked, patients often experience dry mouth and skin, increased heart rate, blurred vision, and difficulty in urinating. In severe cases, blocking acetylcholine may cloud thinking and cause delirium.
Chronic obstructive pulmonary disease —A disorder characterized by the decreasing ability of the lungs to adequately ventilate.
Dopamine —A chemical in brain tissue that serves to transmit nerve impulses (is a neurotransmitter) and helps to regulate movement and emotions.
Glaucoma —A group of eye diseases characterized by increased pressure within the eye significant enough to damage eye tissue and structures. If untreated, glaucoma results in blindness.
Mania —An elevated or euphoric mood or irritable state that is characteristic of bipolar I disorder. This state is characterized by mental and physical hyperactivity, disorganization of behavior, and inappropriate elevation of mood.
Neurotransmitter —A chemical in the brain that transmits messages between neurons, or nerve cells.
Psychotic —Having a mental disorder characterized by disturbances of personality and a loss of normal association with reality.
Respiratory depression —A significant impairment of the respiratory system.
difficulties, irregular heartbeat, significant changes in blood pressure, increased sweating, severe stiffness, extreme weakness, and unusually pale skin. Patients who experience these symptoms should stop using the medication immediately, as these symptoms are considered an emergency. More common but less serious side effects include uncontrolled movement of the arms or legs, lip smacking, unusual movements of the tongue, puffing of the cheeks, and uncontrolled chewing movements. These symptoms should also be reported immediately to a doctor.
More common and even less serious side effects include difficulty in speaking or swallowing, restlessness, stiffness of arms and legs, trembling, and loss of balance. These symptoms also need to be reported to a doctor. Less common and not especially significant side effects include urination problems, muscle spasms, skin rash, and severe constipation. Rare and not particularly serious side effects include uncontrolled twisting and movement of the neck, fever, sore throat, unusual bleeding, yellowing of the eyes or skin, and changes in facial expression.
Overdose symptoms include significant drowsiness, severe dizziness, significant breathing difficulties, severe weakness, trembling muscles, and severe uncontrolled movements.
Interactions
Loxapine should not be combined with anticholinergic drugs because of the potential of decreased anti-psychotic effects. Loxapine should not be combined with bromocriptine because the combination can decrease the effectiveness of bromocriptine in patients with pituitary tumors. The combination of loxapine with lithium increases the toxicity of both drugs significantly. Likewise, loxapine and lorazepam should not be combined because the combination of the two has produced very low blood pressure, severe drowsiness, and respiratory depression in rare cases.
See alsoAnxiety and anxiety disorders; Depression and depressive disorders.
Resources
BOOKS
Consumer Reports Complete Drug Reference. 2002 ed. Denver: Micromedex Thomson Healthcare, 2001.
Ellsworth, Allan J., and others. Mosby’s Medical Drug Reference. 2001-2002. St.Louis: Mosby, 2001.
Preston, John D., John H. O’Neal, and Mary C. Talaga. Handbook of Clinical Psychopharmacology for Therapists. 4th ed. Oakland, CA: New Harbinger Publications, 2004.
PERIODICALS
Bourin, Michel, Olivier Lambert, and Bernard Guitton. “Treatment of Acute Mania—From Clinical Trials to Recommendations for Clinical Practice.” Human Psychopharmacology: Clinical and Experimental 20.1 (Jan. 2005): 15–26.
Janowsky, David S., and others. “Minimally Effective Doses of Conventional Antipsychotic Medications Used to Treat Aggression, Self-Injurious and Destructive Behaviors in Mentally Retarded Adults.” Journal of Clinical Psychopharmacology 25.1 (Feb. 2005): 19–25.
Reinblatt, Shauna P., and others. “Advanced Pediatric Psychopharmacology: Loxapine Treatment in an Autistic Child with Aggressive Behavior: Therapeutic Challenges.” Journal of Child and Adolescent Psychopharmacology 16.5 (Oct. 2006): 639–43.
Mark Mitchell, MD
Ruth A. Wienclaw, PhD