The USCIS followed up on plans announced last fall to increase the vailidity period of TN visas from 1 year to 3 years. This applies to both new admissions as well as extensions. The proposed rule is expected to be published in the Federal Register shortly.

A range of Mexican and Canadian healthcare occupations qualify for the TN visa, for occupations such as:

Dentist, Dietitian, Medical Laboratory Technologist (Canada)/Medical Technologist (Mexico and the United States), Nutritionist, Occupational Therapist, Pharmacist, Physician (teaching or research only), Physiotherapist/Physical Therapist, Psychologist, Recreational Therapist, Registered Nurse, and Veterinarian.

UPDATE: Here is the published Fed Reg notice.