Nursing Mother Taking Antibiotics for Gum Inflammation Regarding the Fast

I am nursing a 3-month-old baby and have started taking antibiotics due to gum inflammation.What is the halacha regarding fasting Tisha Be'Av?

Shalom u'vracha 

Regarding nursing – one should begin the fast. However, if there is a lack of milk, she should immediately break the fast and drink a large amount.

If there is significant weakness, she should also break the fast.

It is important to try to rest in an air-conditioned place.

Regarding taking antibiotics – if the antibiotics add to the weakness caused by nursing, she should not fast.

In general, regarding someone who is sick and requires antibiotics, the ruling of our teacher, HaRav Amram Fried shlit”a, is as follows:

• If there is a fever, or the person is weak or feeling unwell – they may eat and drink as usual.
• If there is no fever and the person feels fine – during the first five days of treatment, they may take the antibiotics on Tisha B’Av without eating or drinking beforehand, since most types of antibiotics do not require eating, except for the types listed below:
• Types of antibiotics that do require eating beforehand include:
  sulfa-based medications, strong antibiotics for gallbladder or kidney infections — in such cases, one is exempt from fasting and should eat and drink normally.
• After five days, if there is no fever and the person feels fine – the general instruction is to take the medication before and after the fast.

For example:

• Twice-daily antibiotics (e.g., Augmentin): take the evening dose before the fast begins (even if it's earlier than usual), and then after the fast, take the next dose. Four hours later, to compensate (even skipping one dose in a day is not critical.)
• Three-times-daily antibiotics (e.g., Cefovit): take the second pill before the fast. Skip the third pill during the fast. After the fast, take one pill, and four hours later another. One pill may be skipped, or alternatively, two pills can be taken right after the fast and one more four hours later—either way is acceptable it's really based on personal preference.