On my bottle of pills it says TRIAM/HCTZ 37.5-25 CAP SANDOZ whats that mean , what are side effect?

It means the pills contain 37.5mg of triamterene and 25mg of hydrochlorothiazide.

Hydrochlorothiazide is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention.

Triamterene is a potassium-sparing diuretic that also prevents your body from absorbing too much salt and keeps your potassium levels from getting too low.

The combination of hydrochlorothiazide and triamterene is used to treat fluid retention (edema) and high blood pressure (hypertension).

https://www.drugs.com/mtm/hydrochlorothiazide-and-triamterene.html

A comprehensive list of side effects of hydrochlorthiazide and triamterene are in the links below.

https://www.drugs.com/sfx/hydrochlorothiazide-side-effects.html

https://www.drugs.com/sfx/triamterene-side-effects.html