A rescreening of the hormones should be done to look for the hormonal aberrations responsible for the hot flashes. Abnormal thyroid or adrenal gland functions can be responsible for these symptoms. Otherwise it can be considered as premenstrual syndrome (PMS). Most evidence suggests that PMS results from the alterations in or interactions between the levels of sex hormones and brain chemicals known as neurotransmitters. Following measures can be helpful;
1) Dietary restriction of coffee, tea, cola soft drinks, and chocolate.
2) Alternative therapies; St. John's wort, hyssop, sage, and black walnut bark can be brewed into a tea. Evening primrose oil may also be effective.
3) Medications like Gabapentin, Clonidine, Atropine, Propranolol (prescription products)
4) Following would be helpful (if you do);
a) quit smoking;
b) reduce alcohol intake; and
c) reduce intake of refined sugars.
5) Mild aerobic exercises
Please feel free for your follow up questions.