What Does "Reasonable and Necessary" Mean for Medications in Insurance Claims?

The definitive guide to assessing medication reasonableness across workers compensation, NDIS, CTP, and life insurance.

Published: 4 April 2026

Definition: What Are Reasonable and Necessary Medications?

In insurance claims management, a medication is "reasonable and necessary" when it is clinically indicated for the diagnosed condition, supported by evidence-based practice, appropriately dosed and timed, and cost-effective relative to the benefit provided to the claimant. This concept sits at the heart of entitlement decisions across workers compensation, NDIS, CTP, and life insurance schemes in Australia.

The term "reasonable and necessary" is not fixed. It shifts slightly across different legislative frameworks, but the core principle remains consistent: the medication must serve a legitimate therapeutic purpose that directly supports the claimant's recovery, functional improvement, or disability management within the scope of the scheme.

The Four Core Principles of Reasonable and Necessary Medications

When assessing whether a medication meets the reasonable and necessary threshold, you should evaluate four interconnected principles:

1. Clinical Effectiveness

The medication must have demonstrated efficacy for the specific condition being treated. This means there should be evidence, ideally from clinical trials or recognised treatment guidelines, that the drug works for that indication. For example, metformin is clinically effective for type 2 diabetes, but prescribing it for weight loss alone in a claimant without diabetes may not meet the clinical effectiveness threshold. You should check whether the prescriber is using the medication for its approved indication or for off-label use, and whether off-label use is supported by credible evidence.

2. Safety and Quality

The medication must be safe for the individual claimant, considering their age, renal and hepatic function, other medications, and comorbidities. A medication listed on the Pharmaceutical Benefits Scheme (PBS) or approved by the Therapeutic Goods Administration (TGA) carries inherent quality assurance, but safety also depends on appropriate dosing, monitoring, and duration of therapy. If a claimant is on a medication at a dose substantially higher than standard, or for a duration that exceeds evidence-based recommendations, the safety principle may not be met.

3. Appropriateness to the Claimant and the Treatment Goal

The medication must be suitable for this particular claimant and aligned with the stated treatment goal. A second-line antidepressant may be appropriate for one claimant but not another, depending on tolerability, prior medication history, and concurrent health conditions. Appropriateness also asks: does this medication support functional improvement, pain relief, or symptom control that enables the claimant to engage in rehabilitation or return-to-work activities? If a medication is masking pain but preventing engagement in rehabilitation, its appropriateness may be questionable.

4. Cost-Effectiveness

The cost of the medication must be proportionate to the benefit provided. Cost-effectiveness does not mean cheapest; it means value for money. If a more expensive branded medicine offers no additional clinical benefit over a cheaper generic equivalent, the expensive option is not cost-effective. Similarly, if a medication costs significantly more than alternatives without superior outcomes, it may not pass the cost-effectiveness test. This principle protects insurers from unnecessary expenditure while ensuring claimants have access to medications that genuinely improve outcomes.

How Reasonable and Necessary Differs Across Insurance Schemes

While the four core principles apply universally, the legislative and contractual context for "reasonable and necessary" varies across Australian insurance schemes. The table below summarises the key differences:

The Four-Part Test: Assessing Medication Reasonableness

To determine whether a specific medication is reasonable and necessary, apply this four-part test:

How Pharmacist-Led Review Determines Reasonableness

Independent medication review by a pharmacist provides a structured, evidence-based assessment of whether medications meet the reasonable and necessary threshold. During a comprehensive medication review, the pharmacist examines:

• Appropriateness of each medication for the diagnosed condition(s) and the individual claimant
• Dosing relative to clinical guidelines, PBS criteria, and the claimant's age, weight, and organ function
• Duration of therapy and whether continuation is justified by ongoing clinical benefit
• Potential drug-drug interactions, particularly in claimants on multiple medicines
• Adherence and tolerability issues that might suggest a safer or more suitable alternative
• Alignment with functional recovery goals and return-to-work objectives in compensation cases
• Comparative cost-effectiveness of the current regimen against alternatives

The pharmacist then prepares a detailed report that either confirms the reasonableness of current medications or identifies specific concerns, such as off-label use without sufficient evidence, excessive dosing, inappropriate duration, or available alternatives that are equally effective but more cost-effective. This report gives you a defensible, clinically sound basis for decisions about medication entitlement.

Red Flags: Medications That May Not Be Reasonable and Necessary

Watch for these warning signs that a medication may fail the reasonable and necessary test:

• No documented diagnosis for which the medication is indicated: If a claimant is on antidepressants but has no documented depression diagnosis, or on a specific anticonvulsant without a seizure disorder or approved off-label indication, the medication is not clinically indicated.
• Doses substantially exceeding standard recommendations: Opioid doses in the high analgesic range without documented cancer pain or palliative care context, or antidepressant doses at ceiling levels without evidence of efficacy, raise red flags.
• Indefinite prescribing of short-term medications: Benzodiazepines, sedating antihistamines, or other drugs intended for acute or short-term use prescribed for years without documented reassessment are frequently not reasonable.
• Multiple medications for the same condition without justification: Two antidepressants, two anticonvulsants, or multiple pain medications prescribed simultaneously may indicate failure to optimise a single agent, or may be justified in specific cases; clarification is needed.
• Lack of documented response to treatment: If a claimant has been on a medication for months or years without documented improvement in symptoms or functional status, its continued use may not be reasonable.
• No evidence-based justification for off-label use: If a medication is used off-label (outside its approved indication) without reference to credible clinical evidence or guidelines, it may not meet the clinical effectiveness standard.
• High cost without superior outcomes: Branded medications, new agents, or exotic preparations prescribed when equivalent alternatives exist at lower cost may not be cost-effective.
• Medication masking pain or symptoms without enabling functional improvement: In rehabilitation or return-to-work contexts, if a medication merely masks symptoms but prevents engagement in therapy or work, its role in recovery is questionable.

Applying the Framework Across Schemes

The reasonable and necessary framework applies to all insurance schemes, but with different emphases. In workers compensation, the focus is on whether the medication supports return to work and functional recovery from the injury. In NDIS, the emphasis is on whether the medication supports participation in the community and pursuit of participant goals, and whether it represents value for money relative to alternative uses of NDIS funds. In CTP, the assessment is similar to workers compensation but framed around recovery from motor accident injury. In life insurance, the focus is on medical necessity and consistency with the covered condition.

Regardless of scheme, the four core principles (clinical effectiveness, safety, appropriateness, and cost-effectiveness) remain the constant reference point.

Documentation and Defensibility

Your assessment of medication reasonableness must be documented clearly in the claim file. Record:

• The diagnosis for which each medication is prescribed
• The date the medication was commenced and any changes to dose or duration
• Any clinical guidelines or references you consulted to confirm indication and appropriateness
• Cost information, including any consideration of generic alternatives
• Any red flags identified and how you addressed them
• Whether independent pharmacy review was obtained and, if so, the key findings
• The basis for your decision regarding entitlement (approved, approved with condition, or not approved)

This documentation protects you from dispute and provides a clear audit trail should the decision be challenged by the claimant or their legal representative.