🧠 Why Some Medications Can't Be Prescribed by GPs

In the UK, the NHS uses a tiered prescribing system that sometimes prevents GPs from prescribing certain medications, even if those medicines are available elsewhere in the NHS.

Here’s a clear explanation of how and why this happens:

🔒 1. Shared Care or Specialist-Only Medications

Some medicines are designated as “specialist-only” or “shared care” treatments. This means:

• GPs are not authorised to initiate them.

• In some cases, they can continue a prescription once a specialist starts it — but only if a formal shared care agreement is in place.

Examples include:

• Biologics for asthma, ABPA, or autoimmune disease

• High-risk antifungals like voriconazole or posaconazole

• Certain cancer, transplant, or hormone drugs

This system ensures that:

• The medication is closely monitored by someone with specialist knowledge

• Risks like interactions, side effects, and required blood tests are safely managed

📜 2. Local Prescribing Formularies

Each NHS Integrated Care Board (ICB) or local NHS Trust maintains a formulary — a list of medicines approved for use in that area.

• If a medicine isn’t on the local formulary, the GP may be unable to prescribe it, even if NICE (the National Institute for Health and Care Excellence) says it’s effective.

• These decisions are based on local budget priorities, agreements with hospitals, and clinical capacity.

💷 3. Cost Controls and Prior Approvals

Some medications are expensive or highly specialised, and require:

• Prior approval by a funding panel

• A hospital-based consultant to apply for and justify the treatment

GPs usually cannot access these approval pathways directly.

⚠️ 4. Liability and Risk

Even if a GP understands the condition, they may not have:

• Access to monitoring protocols

• Up-to-date knowledge of rare drug interactions or side effects

• The ability to interpret complex blood results needed for safe prescribing

For legal and safety reasons, GPs must follow guidance from their local ICB or NHS England on what they can and can’t prescribe.

✅ What Patients Can Do

• Ask the hospital team if the medication can be prescribed under shared care, and whether your GP has agreed to it.

• Ask your GP to request guidance from the local medicines management team.

• Request a hospital prescription if urgent — but note this often requires collection from hospital pharmacies.