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 be available in generic form.
Loxapine is in the class of drugs known as antipsychotic 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.
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 persons under the age of 16 years have not been established.
Persons 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. Sunscreen with a skin protection factor (SPF) greater than 15 should be used when taking this drug.
Loxapine is typically not used in persons 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 great caution should be exercised when women in these groups use loxapine.
Rare side effects, but ones that need to be reported immediately to a doctor, include seizures, breathing difficulties, irregular heartbeat, significant changes in blood pressure, increased sweating, severe stiffness, extreme weakness, and unusually pale skin. These symptoms are considered an emergency, and the patient should stop using the medication immediately. 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
Overdose symptoms include significant drowsiness, severe dizziness, significant breathing difficulties, severe weakness, trembling muscles, and severe uncontrolled movements.
Loxapine should not be combined with anticholinergic drugs because of the potential of decreased antipsychotic 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.
Consumer Reports Staff, eds. 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.
Hardman, Joel G., Lee E. Limbird, eds. Goodman & Gilman's The Pharmacological Basis of Therapeutics. 10th ed. New York: McGraw-Hill, 2001.
Mosby's GenRx staff. Mosby's GenRx. 9th ed. St. Louis: Mosby, 1999.
Venes, Donald, and others, eds. Taber's Cyclopedic Medical Dictionary19th ed. Philadelphia: F. A. Davis, 2001.
Mark Mitchell, M.D.