Unsure of Cialis dosage

I was given a 20 mg tablet of Cialis by my General Practitioner and i was wondering if i can break the
tablet in half to get a 10 mg dosage? Will this effect the potency of the drug?
She suggested i take 10 mg but its hard to break the 20mg pill and be sure you have a 10 mg dose.

Should i just take the 20mg ?

Thanks in advance

[metropolis]

Yes, you can break the tablet in two to get a 10 mg dose. My urologist told me to do just that. If half a pill works for you, then fine - it will save you a lot of money.