Can dogs have panadol

No!

it thins their blood to dangerous levels. If you have a small breed 5-15 kg, even 250 mg of panadol can be fatal

Correction:

Paracetamol, also known as Panadol, does not thin the blood like aspirin (and ibuprofen) does.

Any reason not to give dogs Paracetamol is because of the risk of liver damage from incorrect dosage. Always check with your vet for correct dosage.