Thioxanthenes (Systemic)

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