Washington Prescription Pads

In addition to the federal requirements, Washington state law requires that every prescription written in this state by a licensed practitioner must be written on a tamper-resistant prescription pad or paper approved by the commission. For the purposes of this section, "tamper-resistant prescription pads or paper" means a prescription pad or paper that has been approved by the commission for use and contains the following characteristics:

• One or more industry-recognized features designed to prevent unauthorized copying of a completed or blank prescription form;
• One or more industry-recognized features designed to prevent the erasure or modification of information written on the prescription form by the practitioner; and
• One or more industry-recognized features designed to prevent the use of counterfeit prescription forms.

All vendors must have their tamper-resistant prescription pads or paper approved by the commission prior to the marketing or sale of pads or paper in Washington state. The commission shall create a seal of approval that confirms that a pad or paper contains all three industry-recognized characteristics required by this section. The seal must be affixed to all prescription pads or paper used in this state. 

Read documentation here and here.

For the federal requirements, you can refer to the official documentation here and here.