Brief Answer:
Kindly check the details given below:

Detailed Answer:
Hi & Welcome to HCM.
I appreciate your concern for the safety of Domtal (Domperidone).

Both the drugs are effective in treating nausea and vomiting.
But it is Doxinate that is usually prescribed to treat the nausea and vomiting seen in early pregnancy ("morning sickness").

Domperidone is a pregnancy Category -C drug.
Which means animal studies have shown an adverse effect on the fetus. However the well-controlled studies in humans failed to show any harmful effects on the growing fetus. Thus medication should be used only if clearly needed during pregnancy.
Since she has taken one tablet of Domstal accidentally it should not be a matter of concern, however she is advised to consult a gynecologist for proper antenatal checkup, like periodic ultrasound, routine urine and blood tests, etc.
Meanwhile let her take iron and folic supplements that are prescribed.

Hope this answers your query.
Best regards.

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