Section 5.1: Texas Prescriptive Authority

Section 5.1: Texas Prescriptive Authority

Prescriptive authority in Texas is divided into two primary categories: independent prescriptive authority and delegated (dependent) prescriptive authority. Understanding who has the legal right to prescribe, what classes of medications they can order, and what restrictions apply is a fundamental area of testing on the Texas MPJE.

Independent Prescriptive Authority

Practitioners with independent prescriptive authority can write prescriptions within their legal scope of practice without supervision or delegation from another practitioner.

Unlimited vs. Limited Independent Scope

Only physicians (MDs and DOs) possess unlimited, independent prescriptive authority. All other independent practitioners are restricted by their professional scope of practice.

Legal Trap: Chiropractors (DC), physical therapists (PT), psychologists (except in very limited military or out-of-state jurisdictions not recognized in Texas), and pharmacists (outside of collaborative practice agreements) do not possess independent prescriptive authority in Texas. A prescription from a chiropractor is completely invalid and must never be filled.

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Optometric Prescriptive Authority: TO vs. OGS

Texas law distinguishes between different levels of optometric licensure, each carrying distinct prescriptive limits. This is a highly tested area on the MPJE.

1. Therapeutic Optometrists (TO)

Therapeutic optometrists are licensed to prescribe:

• Topical ocular pharmaceutical agents (e.g., eye drops for infection, inflammation).
• Over-the-counter (OTC) oral medications.
• A 3-day (72-hour) supply of any analgesic classified as a Schedule III, IV, or V controlled substance (requires a valid DEA registration).
• Oral medications used to treat conditions of the eye or its adnexa (excluding Schedule I and II controlled substances). Historically, this included 10-day supplies of antibiotics, 7-day supplies of NSAIDs, and 3-day supplies of antihistamines; under recent expansions (S.B. 993), they may prescribe appropriate oral medications for these conditions but must strictly observe the 3-day limit on controlled substances.

2. Optometric Glaucoma Specialists (OGS)

An OGS holds advanced certification allowing them to manage glaucoma and prescribe:

• Any topical or oral medication used to treat eye conditions (excluding Schedule I and II controlled substances).
• Oral carbonic anhydrase inhibitors (e.g., acetazolamide) for emergency purposes, followed by a mandatory immediate referral to an ophthalmologist.
• A 3-day (72-hour) supply of Schedule III, IV, or V analgesics.

Glaucoma Management and Referral Rules

Under Texas Occupations Code § 351.3581, an OGS can independently manage glaucoma but must refer the patient to an ophthalmologist within specific clinical thresholds:

1. Patient Age: If the patient is younger than 16 years of age and diagnosed with glaucoma.
2. Specific Glaucoma Subtypes: If the patient is diagnosed with acute closed-angle glaucoma, malignant glaucoma, or neovascular glaucoma.
3. Treatment Failure: If the patient's glaucoma does not respond to non-surgical intervention or if the target intraocular pressure (which must be set at no more than 80% of the patient's initial pressure) is not achieved.
4. Advanced Disease: If the patient displays advanced optic disc, retinal nerve fiber layer, or macular imaging abnormalities combined with visual field loss in both hemifields.

OGS Beta-Blocker Mandate

Before prescribing a beta-blocker (e.g., timolol ophthalmic drops), an OGS must review the patient’s medical history and confirm the patient has had a physical examination within the preceding 180 days. If the patient has not had a physical exam or has a history of congestive heart failure, asthma, bradycardia, or chronic obstructive pulmonary disease (COPD), the OGS must refer the patient to a physician for a physical examination prior to initiating therapy.

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Delegated Prescriptive Authority (APRNs & PAs)

Advanced Practice Registered Nurses (APRNs) and Physician Assistants (PAs) do not have independent prescriptive authority in Texas. They practice under a delegated model through a Prescriptive Authority Agreement (PAA) or facility protocol.

Prescriptive Authority Agreement (PAA)

• Definition: A written, signed, and dated agreement between a delegating physician and an APRN or PA that authorizes the ordering or prescribing of drugs and devices.
• TMB Registration: The delegating physician must register the delegation with the Texas Medical Board (TMB) within 30 days of signing the PAA.
• Ratio Limits: A physician may delegate prescriptive authority to a maximum of 7 active, full-time equivalent (FTE) APRNs or PAs at any given time.
  • Exceptions: The 7-FTE ratio limit does not apply in medically underserved areas (MUAs) or in facility-based practices (such as hospitals or long-term care facilities).

Delegated Controlled Substance Rules

Texas heavily restricts the delegated prescribing of controlled substances by APRNs and PAs:

• Schedules III–V: APRNs and PAs may prescribe Schedule III, IV, and V controlled substances, but the prescription (including refills) is limited to a maximum 90-day supply. Any refill authorization beyond the initial 90 days requires a formal consultation with the delegating physician, which must be documented in the patient’s medical record.
• Schedule II: APRNs and PAs are generally prohibited from prescribing Schedule II controlled substances. There are only two exceptions where Schedule II prescribing is allowed:
  1. Hospital-Based Practice: Under hospital bylaws, for patients admitted to the hospital for 24 hours or longer, or for patients being treated in the hospital's emergency department.
  2. Hospice/Palliative Care: For terminally ill patients receiving hospice care from a certified hospice provider.
• DEA Requirements: APRNs and PAs must obtain their own DEA registration to prescribe controlled substances.
• Prescription Details: The prescription must display the name, address, telephone number, and DEA number of both the delegating physician and the prescribing APRN or PA.

Exam Tip: If you receive a prescription for a Schedule II controlled substance written by a Physician Assistant at a local outpatient clinic (not a hospital or hospice setting), it is legally invalid. Under standard PAAs, Schedule II prescribing is strictly prohibited outside of the hospital-based or hospice-based exceptions.