A QCD is an exclusion from income, not a deduction on Schedule A, so the 50%-of-AGI limit on charitable deductions does not apply. For someone eligible to make a QCD, the only limitation is that the total of your QCDs in a given year cannot exceed $100,000.
Also be aware that some States do not recognize QCD's, so you may owe state taxes.
The following is from IRS Publication 590-B at https://www.irs.gov/publications/p590b#en_US_2016_publink100041439
Qualified charitable distributions.
A qualified charitable distribution (QCD) is generally a nontaxable distribution made directly by the trustee of your IRA (other than a SEP or SIMPLE IRA) to an organization eligible to receive tax deductible contributions. You must be at least age 70½ when the distribution was made. Also, you must have the same type of acknowledgment of your contribution that you would need to claim a deduction for a charitable contribution. See Records To Keep in Pub. 526.
The maximum annual exclusion for QCDs is $100,000. Any QCD in excess of the $100,000 exclusion limit is included in income as any other distribution. If you file a joint return, your spouse can also have a QCD and exclude up to $100,000. The amount of the QCD is limited to the amount of the distribution that would otherwise be included in income. If your IRA includes nondeductible contributions, the distribution is first considered to be paid out of otherwise taxable income.
A QCD will count towards your required minimum distribution,