THIOXANTHENES (Systemic)

Some commonly used brand names are:

In the U.S.—

  • Navane 3
  • Taractan 1
  • Thiothixene HCl Intensol 3

In Canada—

  • Fluanxol 2
  • Fluanxol Depot 2
  • Navane 3

Note:

For quick reference, the following thioxanthenes are numbered to match the corresponding brand names.

This information applies to the following medicines:
1. Chlorprothixene (klor-proe-THIX-een)
2. Flupenthixol (floo-pen-THIX-ole)*
3. Thiothixene (thye-oh-THIX-een)
* Not commercially available in the U.S.
† Not commercially available in Canada
‡ Generic name product may be available in the U.S.

Category

  • Antipsychotic—Chlorprothixene; Flupenthixol; Thiothixene

Description

This medicine belongs to the family of medicines known as thioxanthenes (thye-oh-ZAN-theens). It is used in the treatment of nervous, mental, and emotional conditions. Improvement in such conditions is thought to result from the effect of the medicine on nerve pathways in specific areas of the brain.

Thioxanthene medicines are available only with your doctor's prescription, in the following dosage forms:

  • Oral
  • Chlorprothixene
    • Suspension (U.S.)
    • Tablets (U.S.)
  • Flupenthixol
    • Tablets (Canada)
  • Thiothixene
    • Capsules (U.S. and Canada)
    • Solution (U.S.)
  • Parenteral
  • Chlorprothixene
    • Injection (U.S.)
  • Flupenthixol
    • Injection (Canada)
  • Thiothixene
    • Injection (U.S.)

Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For thioxanthenes, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to thioxanthene or to phenothiazine medicines. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Studies have not been done in pregnant women. Although animal studies have not shown that thioxanthenes cause birth defects, the studies have shown that these medicines cause a decrease in fertility and fewer successful pregnancies.

Breast-feeding—It is not known if thioxanthenes pass into the breast milk. However, similar medicines for nervous, mental, or emotional conditions do pass into breast milk and may cause drowsiness and increase the risk of other problems in the nursing baby. Be sure you have discussed the risks and benefits of this medicine with your doctor.

Children—Certain side effects, such as muscle spasms of the face, neck, and back, tic-like or twitching movements, inability to move the eyes, twisting of the body, or weakness of the arms and legs, are more likely to occur in children, who are usually more sensitive than adults to the side effects of thioxanthenes.

Older adults—Constipation, dizziness or fainting, drowsiness, dryness of mouth, trembling of the hands and fingers, and symptoms of tardive dyskinesia (such as rapid, worm-like movements of the tongue or any other uncontrolled movements of the mouth, tongue, or jaw, and/or arms and legs) are especially likely to occur in elderly patients, who are usually more sensitive than younger adults to the effects of thioxanthenes.

Other medicines—Although certain medicines should not be used together at all, in other cases 2 different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking thioxanthenes, it is especially important that your health care professional know if you are taking any of the following:

  • Amoxapine (e.g., Asendin) or
  • Methyldopa (e.g., Aldomet) or
  • Metoclopramide (e.g., Reglan) or
  • Metyrosine (e.g., Demser) or
  • Other antipsychotics (medicine for mental illness) or
  • Pemoline (e.g., Cylert) or
  • Pimozide (e.g., Orap) or
  • Promethazine (e.g., Phenergan) or
  • Rauwolfia alkaloids (alseroxylon [e.g., Rauwiloid], deserpidine [e.g., Harmonyl], rauwolfia serpentina [e.g., Raudixin], reserpine [e.g., Serpasil]) or
  • Trimeprazine (e.g., Temaril)—Taking these medicines with thioxanthenes may increase the chance and severity of certain side effects
  • Central nervous system (CNS) depressants (medicine that causes drowsiness) or
  • Tricyclic antidepressants (medicine for depression)—Taking these medicines with thioxanthenes may add to the CNS depressant effects
  • Epinephrine (e.g., Adrenalin)—Severe low blood pressure (hypotension) and fast heartbeat may occur if epinephrine is used with thioxanthenes
  • Levodopa (e.g., Sinemet)—Thioxanthenes may keep levodopa from working properly in the treatment of Parkinson's disease
  • Quinidine (e.g., Quinidex)—Unwanted effects on your heart may occur

Other medical problems—The presence of other medical problems may affect the use of thioxanthenes. Make sure you tell your doctor if you have any other medical problems, especially:

  • Alcohol abuse—Drinking alcohol will add to the central nervous system (CNS) depressant effects of thioxanthenes
  • Blood disease or
  • Enlarged prostate or
  • Glaucoma or
  • Heart or blood vessel disease or
  • Lung disease or
  • Parkinson's disease or
  • Stomach ulcers or
  • Urination problems—Thioxanthenes may make the condition worse
  • Liver disease—Higher blood levels of thioxanthenes may occur, increasing the chance of side effects
  • Reye's syndrome—The risk of liver problems may be increased
  • Seizure disorders—The risk of seizures may be increased

Proper Use of This Medicine

This medicine may be taken with food or a full glass (8 ounces) of water or milk to reduce stomach irritation.

For patients taking thiothixene oral solution :

  • This medicine must be diluted before you take it. Just before taking, measure the dose with the specially marked dropper. Mix the medicine with a full glass of water, milk, tomato or fruit juice, soup, or carbonated beverage.

Do not take more of this medicine or take it more often than your doctor ordered . This is particularly important when this medicine is given to children, since they may react very strongly to its effects.

Sometimes this medicine must be taken for several weeks before its full effect is reached .

Dosing—The dose of these medicines will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.

The number of capsules or tablets or the amount of liquid that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking thioxanthenes.

  • For chlorprothixene
  • For treatment of psychosis:
    • Oral dosage forms (suspension or tablets):
      • Adults and teenagers—25 to 50 milligrams (mg) three or four times a day.
      • Children 6 to 12 years of age—10 to 25 mg three or four times a day.
      • Children up to 6 years of age—Use and dose must be determined by your doctor.
    • Injection dosage form:
      • Adults and teenagers—25 to 50 mg, injected into a muscle, three or four times a day.
      • Children up to 12 years of age—Use and dose must be determined by your doctor.
  • For flupenthixol
  • For treatment of psychosis:
    • Oral dosage form (tablets):
      • Adults—To start, 1 milligram (mg) three times a day. Your doctor may increase your dose if needed, depending on your condition.
      • Children—Use and dose must be determined by your doctor.
    • Long-acting injection dosage form:
      • Adults—To start, 20 to 40 milligrams (mg) injected into a muscle. Your doctor will determine whether your dose needs to be changed, depending on your condition.
      • Children—Use and dose must be determined by your doctor.
  • For thiothixene
  • For treatment of psychosis:
    • Oral dosage forms (capsules and solution):
      • Adults and teenagers—To start, 2 milligrams (mg) three times a day, or 5 mg two times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 60 mg a day.
      • Children up to 12 years of age—Use and dose must be determined by your doctor.
    • Injection dosage form:
      • Adults and teenagers—4 milligrams (mg), injected into a muscle, two to four times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 30 mg a day.
      • Children up to 12 years of age—Use and dose must be determined by your doctor.

Missed dose—If you miss a dose of this medicine, take it as soon as possible. However, if it is within 2 hours of your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—To store this medicine:

  • Keep out of the reach of children.
  • Store away from heat and direct light.
  • Do not store the capsule or tablet form of this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
  • Keep the liquid form of this medicine from freezing.
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

Your doctor should check your progress at regular visits. This will allow the dosage of the medicine to be adjusted when necessary and also will reduce the possibility of side effects.

Do not stop taking this medicine without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping completely. This is to prevent side effects and to prevent your condition from becoming worse.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that slow down the nervous system, possibly causing drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any such depressants while you are using this medicine .

Do not take this medicine within an hour of taking antacids or medicine for diarrhea. Taking them too close together may make this medicine less effective.

Before having any kind of surgery, dental treatment, or emergency treatment, tell the medical doctor or dentist in charge that you are using this medicine . Taking thioxanthenes together with medicines that are used during surgery or dental or emergency treatments may increase the CNS depressant effects.

This medicine may cause some people to become drowsy or less alert than they are normally, especially during the first few weeks the medicine is being taken. Even if you take this medicine only at bedtime, you may feel drowsy or less alert on arising. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert .

Dizziness, lightheadedness, or fainting may occur while you are taking this medicine , especially when you get up from a lying or sitting position. Getting up slowly may help. If the problem continues or gets worse, check with your doctor.

This medicine may make you sweat less, causing your body temperature to increase. Use extra care not to become overheated during exercise or hot weather while you are taking this medicine , since overheating may result in heat stroke. Also, hot baths or saunas may make you feel dizzy or faint while you are taking this medicine.

Thioxanthenes may cause your skin to be more sensitive to sunlight than it is normally. Exposure to sunlight, even for brief periods of time, may cause a skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking this medicine:

  • Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.
  • Wear protective clothing, including a hat. Also, wear sunglasses.
  • Apply a sun block product that has a skin protection factor (SPF) of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your health care professional.
  • Apply a sun block lipstick that has an SPF of at least 15 to protect your lips.
  • Do not use a sunlamp or tanning bed or booth.

If you have a severe reaction from the sun, check with your doctor .

This medicine may cause dryness of the mouth. For temporary relief, use sugarless gum or candy, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

If you are taking a liquid form of this medicine, try to avoid spilling it on your skin or clothing . Skin rash and irritation have been caused by similar medicines.

If you are receiving this medicine by injection:

  • The effects of the long-acting injection form of this medicine may last for up to 3 weeks. The precautions and side effects information for this medicine applies during this period of time .

Side Effects of This Medicine

Along with their needed effects, thioxanthenes can sometimes cause serious side effects. Tardive dyskinesia (a movement disorder) may occur and may not go away after you stop using the medicine. Signs of tardive dyskinesia include fine, worm-like movements of the tongue, or other uncontrolled movements of the mouth, tongue, cheeks, jaw, or arms and legs. Other serious but rare side effects may also occur. Some of these side effects, including severe muscle stiffness, fever, unusual tiredness or weakness, fast heartbeat, difficult breathing, increased sweating, loss of bladder control, and seizures, may be the sign of a condition called neuroleptic malignant syndrome. You and your doctor should discuss the good this medicine will do as well as the risks of taking it .

Although not all of these side effects may occur, if they do occur they may need medical attention.

Stop taking this medicine and get emergency help immediately if any of the following side effects occur:

Rare

Convulsions (seizures); difficulty in breathing; fast heartbeat; high fever; high or low (irregular) blood pressure; increased sweating; loss of bladder control; muscle stiffness (severe); unusually pale skin; unusual tiredness

Also, check with your doctor as soon as possible if any of the following side effects occur:

More common

Difficulty in talking or swallowing; inability to move eyes; lip smacking or puckering; loss of balance control; mask-like face; muscle spasms, especially of the neck and back; puffing of cheeks; rapid or worm-like movements of tongue; restlessness or need to keep moving (severe); shuffling walk; stiffness of arms and legs; trembling and shaking of fingers and hands; twisting movements of body; uncontrolled chewing movements; uncontrolled movements of the arms and legs

Less common

Blurred vision or other eye problems; difficult urination; fainting; skin discoloration; skin rash

Rare

Hot, dry skin or lack of sweating; increased blinking or spasms of eyelid; muscle weakness; sore throat and fever; uncontrolled twisting movements of neck, trunk, arms, or legs; unusual bleeding or bruising; unusual facial expressions or body positions; yellow eyes or skin

Symptoms of overdose

Difficulty in breathing (severe); dizziness (severe); drowsiness (severe); muscle trembling, jerking, stiffness, or uncontrolled movements (severe); small pupils; unusual excitement; unusual tiredness or weakness (severe)

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Constipation; decreased sweating; dizziness, lightheadedness, or fainting; drowsiness (mild); dryness of mouth; increased appetite and weight; increased sensitivity of skin to sunlight (skin rash, itching, redness or other discoloration of skin, or severe sunburn); stuffy nose

Less common

Changes in menstrual period; decreased sexual ability; swelling of breasts (in males and females); unusual secretion of milk

After you stop taking this medicine your body may need time to adjust, especially if you took this medicine in high doses or for a long time. If you stop taking it too quickly, the following withdrawal effects may occur and should be reported to your doctor:

Dizziness; nausea and vomiting; stomach pain; trembling of fingers and hands; uncontrolled, continuing movements of mouth, tongue, or jaw

Although not all of the side effects listed above have been reported for all thioxanthenes, they have been reported for at least one of them. However, since these medicines are very similar, any of the above side effects may occur with any of them.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Revised: 08/18/1998

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