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:
- Aripiprazole (Abilify)
- Asenapine (Saphris)
- Brexpiprazole (Rexulti)
- Cariprazine (Vraylar)
- Clozapine (Clozaril)
- Iloperidone (Fanapt)
- Lumateperone tosylate (Caplyta)
- Lurasidone (Latuda)
- Olanzapine (Zyprexa)
- Paliperidone (Invega)
- Quetiapine (Seroquel)
- Risperidone (Risperdal)
- Ziprasidone (Geodon)
“Typical” antipsychotics are older medicines. They include:
- Chlorpromazine (Thorazine)
- Fluphenazine (Prolixin)
- Haloperidol (Haldol)
- Perphenazine (Trilafon)
- Thioridazine (Mellaril)
Some of these medicines come in long-lasting injectable forms that 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
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.
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.
- Citalopram (Celexa)
- Escitalopram (Lexapro)
- Fluoxetine (Prozac, Sarafem, Symbyax)
- Paroxetine (Paxil, Paxil CR, Pexeva)
- Sertraline (Zoloft)
- Vilazodone (Viibryd)
Other antidepressants your doctor should be aware of include:
- Desvenlafaxine (Pristiq)
- Duloxetine (Cymbalta)
- Esketamine (Spravato)
- Mirtazapine (Remeron)
- Venlafaxine (Effexor)
- Wellbutrin (Buproprion)
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 are often sold over the counter.
Anti-infection 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 heartbeat 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.
Parkinson's drugs. Taking levodopa (Sinemet) 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.
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.
Signs of an Interaction
Call your doctor if you have any of these side effects:
- Dizziness, especially when you stand up
- Excess sleepiness
- Fast or unsteady heartbeat
- Muscle stiffness or spasms
- 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.