Drug Interactions between caffeine / ergotamine and clozapine

Alcohol can increase the nervous system side effects of cloZAPine such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with cloZAPine. Do not use more than the recommended dose of cloZAPine, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

Grapefruit juice may increase the blood levels of certain medications such as ergotamine. You may want to limit your consumption of grapefruit and grapefruit juice during treatment with ergotamine. However, if you have been regularly consuming grapefruit or grapefruit juice with the medication, then it is advisable for you to talk with your doctor before changing the amounts of these products in your diet, as this may alter the effects of your medication. Contact your doctor if your condition changes or you experience increased side effects. Orange juice is not expected to interact.

Consumer information for this interaction is not currently available.

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.

Nicotine may increase the effects of ergotamine in narrowing the blood vessels and decreasing blood flow. A severe decrease in blood flow to the brain and other parts of the body can lead to dangerous side effects. Contact your doctor immediately if you experience coldness, paleness, discoloration, numbness, tingling, or pain in your hands or feet; muscle pain or weakness; severe or worsening headache; blurred vision; severe abdominal pain; chest pain; or shortness of breath while using these medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Information for this minor interaction is available on the professional version.

Information for this minor interaction is available on the professional version.