Schizophrenia Meds: Drug Interactions to Check On

Antipsychotic medicines help keep your schizophrenia under control and prevent symptoms. But these medicines sometimes don't mix well with other drugs you take. They can also interact with herbal supplements you buy without a prescription, and with some foods and drinks.

The result can be side effects, or even problems with your medicines not working as well as they should. The effects of combining these drugs can range from constipation to low blood pressure. Some interactions are mild. Others are more serious.

Ask your doctor what signs to look for, and when to call.

Your Schizophrenia Medicines

Two types of antipsychotic drugs treat schizophrenia:

“Atypical” antipsychotics are newer, and have fewer side effects than the older drugs. They include:

“Typical” antipsychotics are older medicines. They include:

Some of these medicines come in long lasting injectable forms (insert link to WebMD injectable antipsychotics which you take only once every 1-3 months. This can help with making blood levels more regular and help with not forgetting to take the medications.

Many of these medicines interact with other drugs you might take. One study found that haloperidol interacts with 58 different drugs. And clozapine interacts with 55 drugs. Antipsychotics can also interact with herbal supplements, foods, and drinks.

Drugs, Supplements, and Foods

If you take antipsychotic medicines, you’ll also want to watch out for these possible problems:

Foods and Drinks

Alcohol. Antipsychotic medicines already cause drowsiness as a side effect. Drinking alcohol with your medicine can make you extra sleepy.

Caffeine. Coffee and other caffeinated drinks and foods like chocolate can raise the amount of Clozaril in your blood. This could lead to more side effects.

Grapefruit. This fruit and its juice can dangerously raise blood levels of some antipsychotic drugs, such as quetiapine (Seroquel) ziprasidone (Geodon) and lurasidone (Latuda).

Nicotine: Smoking can decrease levels of medicines for schizophrenia which are active in your body. Let your doctor know if you smoke or use nicotine.

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Other Drugs

Anticholinergic drugs for COPD or incontinence. Clozaril, chlorpromazine, and other antipsychotic drugs cause constipation as a side effect. Anticholinergic drugs such as ipratropium (Atrovent), ipratropium plus albuterol (Combivent), or tiotropium (Spiriva), used in chronic obstructive pulmonary disease (COPD), can make constipation worse.

Antidepressants. Older tricyclic antidepressants can cause an irregular heartbeat if you take them with schizophrenia drugs.

Both tricyclic and SSRI (selective serotonin reuptake inhibitor) antidepressants can make seizures more likely, usually when given at high doses. SSRIs include:

Tricyclics include:

Other antidepressants your doctor should be aware of include:

The SSRI fluvoxamine (Luvox) can also dangerously raise blood levels of clozapine, haloperidol, and olanzapine.

Your doctor can check to see if you’re on the right type of medicine for your depression.

Antihistamines. These medicines are used to treat colds and allergies, and  are used as sleep aids. They can make you more drowsy., especially when combined with other medications. They rea often sold over the counter.

Anti-ifection medicines: Medicines to treat infections, especially HIV and tuberculosis can significantly change blood levels of antipsychotic medications.

Benzodiazepines. These meds, which include alprazolam (Xanax), clonazepam (Klonopin), and diazepam (Valium) treat anxiety. They can make you extra drowsy when you take them with antipsychotic medicines.

Blood pressure medicines. ACE inhibitors, beta-blockers, calcium channel blockers, and other blood pressure drugs can interact with antipsychotics. Together, they may make your heart beat in an abnormal rhythm or lower your blood pressure too much.

Heart rhythm drugs. Doctors may prescribe medicines such as amiodarone (Cordarone), disopyramide (Norpace), and sotalol (Betapace) to treat an abnormal heart rhythm. But when you take them with antipsychotic drugs, these medicines can cause even more serious heart rhythm problems.

Mood stabilizers and anti-seizure medicines. Meidince such as carbamazepine (Tegretol), phenytoin (Dilantin), and valproate (Depakote) can alter blood levels of anticsychotic medications. 

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Opioid pain relievers. These pain-relieving drugs can make you very sleepy.

Parkinson's drugs. Taking levodopa or other medications to treat Parkinson's disease with an antipsychotic can make both drugs less effective. This interaction could bring abnormal muscle movements and make your schizophrenia symptoms worse.

Corticosteroids. Taking these plus schizophrenia medicines can cause weight gain and raise your chance of having diabetes.

 

Herbal Supplements

Chasteberry. Some people take this dietary supplement for menopause symptoms, infertility, and other conditions. It could interfere with antipsychotic drugs and make them less effective.

Ginkgo biloba. This supplement can boost the effects of antipsychotic drugs in your body. It might also cause seizures in some people. Taking ginkgo plus risperidone (Risperdal) might also make a man more likely to have an erection that lasts more than 4 hours -- a condition called priapism.

Ginseng. This supplement can raise the effects of antipsychotic drugs, which could make you more likely to have side effects.

Kava. This herb is used to treat anxiety and improve sleep. It can boost side effects from chlorpromazine.

Signs of an Interaction

Call your doctor if you have any of these side effects:

  • Constipation
  • Dizziness, especially when you stand up
  • Excess sleepiness
  • Fast or unsteady heartbeat
  • Muscle stiffness or spasms
  • Seizures
  • Weight gain

Use Schizophrenia Drugs Safely

Every time you get a new prescription, go over your whole list of medicines with your doctor and pharmacist. Ask them to check that none of your prescriptions you take interact with each other.

Tell your doctor about any vitamins, supplements, and over-the-counter drugs you buy without a prescription.

Always read the medicine label and follow the directions your doctor or pharmacist gave you. And if you have any signs of an interaction, call your doctor.

WebMD Medical Reference Reviewed by Jennifer Casarella on August 06, 2019

Sources

SOURCES:

Agins, Alan P. ADA Quick Guide to Drug-Supplement Interactions, 2011.

BioMed Research International: "Characterization of schizophrenia adverse interactions through a network approach and drug classification."

British Journal of Medical Practitioners: "Drug Interactions With Grapefruit Juice."

FDA: "Avoid Food-Drug Interactions," "Drug Interactions: What You Should Know,” “Selective Serotonin Reuptake Inhibitors (SSRIs) Information.”

African Journal of Traditional, Complementary and Alternative Medicines: "Patient counseling about herbal-drug interactions."

Mayo Clinic: "Schizophrenia: Treatment."

Mayo Clinic Proceedings: "Association between priapism and concurrent use of risperidone and ginkgo biloba."

Medicines and Healthcare products Regulatory Agency: "Antipsychotics learning module."

National Center for Complementary and Integrative Health: "Chasteberry."

Progress in Neurology and Psychology: "Identifying and reducing the risk of antipsychotic drug interactions."

Standard Process: "Potential herb-drug interactions for commonly used herbs."

Winterton, M. Pharmacology for the Primary Care Provider, 2013.

UpToDate.

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