Severe. These medicines may interact and cause very harmful effects and are usually not taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
The cause of the interaction is not known.
What might happen:
You may experience an increased risk for seizures.
What you should do about this interaction:
Contact your healthcare professionals (e.g. doctor or pharmacist) as soon as possible about using these two medicines together. They may already be aware of this interaction and may be monitoring you for it. It may be necessary to stop your dose of phenothiazine at least 48 hours prior to giving you metrizamide. Do not start, stop, or change the dosage of any medicine before checking with them first.
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