Tadalafil should not be given with:
Ref. KDT. Page. 190
TALADAFIL:

More potent and longer acting congener of sildenafil
t1⁄2 18 hours and duration of action 24–36 hours.
Acts faster
Side effects, risks, contraindications and drug interactions are similar to sildenafil.
Because of its longer lasting action, nitrates are contraindicated for 36–48 hours after tadalafil.  (vasodilators)
Vasodilator
Antibiotics
Vasoconstrictors
Valproate