Question

What time can I take isoniazid with TLD, cotrimoxazole and multivitamins?

27 November 2025. Related: All topics, Drug interactions.

What’s the ideal time should I take isoniazid?

I am taking TLD at 1:30 PM, then cotrimoxazole on 8:30 PM along with my multivitamins.

Answer

Answer: Simon Collins

Hi there

Thanks – please don’t worry about TLD and the isoniazid or cotrimoxazole.

The online drug interaction database at Liverpool University shows there are no interactions between any of these meds:
hiv-druginteractions.org/checker

This means that you can take the isoniazid whenever you want to.

This includes taking it at the same time as your HIV meds and the cotrimoxazole.

The multivitamins can interaction with TLD though and make the TLD less effective if taken at the same time. The multivitamin need to be taken either 2 hours before TLD or 6 hours afterwards. See:
i-base.info/guides/14970