Therapeutic Purpose under Section 4 of the Medicines Act 1981

1. Key takeaways

Whether a product enters New Zealand medical device regulation is first tested against s 4 of the Medicines Act 1981 (1981 No 118). Section 4 was replaced by s 7 of the Medicines Amendment Act 2013 (2013 No 141), in force from 1 July 2014, and defines therapeutic purpose. GRZAN’s verification groups the matters listed in s 4 into 6 classes: first, preventing, diagnosing, monitoring, alleviating, treating, curing or compensating for a disease or injury and the like; second, influencing, suppressing or modifying a physiological process; third, testing susceptibility to a disease or condition; fourth, influencing, controlling or preventing conception; fifth, testing for pregnancy; and sixth, investigating, replacing or modifying a part of the anatomy of a person.

Therapeutic purpose is not device-exclusive in New Zealand: it is referenced by s 3A(a) and by the medicines provisions alike, so s 4 cannot by itself answer device or medicine; it answers only whether the product falls within the therapeutic regulatory field of view. The real boundary work is done by s 3A: once a therapeutic purpose exists, the next question is whether the principal intended action is achieved by pharmacological, immunological or metabolic means. The two provisions work in tandem, and neither suffices alone.

This tandem structure has three practical consequences. First, a product without a therapeutic purpose is outside device regulation altogether, as with ordinary consumer goods. Second, a product with a therapeutic purpose whose principal action is pharmacological falls under medicines. Third, device scope is not drawn by rehabilitation type; as long as a claimed function maps onto one of the six classes in s 4, the claim itself pulls the product into scope.

What follows from device characterisation? No approval process starts: no premarket approval, no registration certificate, no Medsafe technical review; the Sponsor’s duty is to notify WAND after the device arrives. Characterisation decides whether to notify, not whether to be reviewed.

2. Legal basis

The verified sources below locate s 4 within the definitional chain that governs whether a product is regulated as a device.

3. Expert insights

Insight 1: s 4 is a scope provision, not a classification provision. Some companies treat s 4 as a test of high risk, which misreads it. s 4 decides only whether the regulatory field of view applies; risk level is handled separately by the 22 classification rules in Schedule 2 of the 2003 Regulations. Between them sits an intermediate step: s 4 first decides whether the product is regulated at all, s 3A then decides whether it is regulated as a device or a medicine, and Schedule 2 last decides how intensively. The three steps run in series; jumping any one distorts the conclusion.

Insight 2: Claims create purpose, and this is the most common detonator of boundary disputes. Several expressions in s 4, particularly influencing, suppressing or modifying a physiological process, are very broad. A piece of hardware originally positioned as a general wellness electronics product can be found to assert a therapeutic purpose under s 4 the moment marketing mentions improving blood circulation or regulating sleep rhythms. Regulation 7(b) of the 2003 Regulations requires the Sponsor to declare that the product is recommended only by intended purpose, and reg 25(2) of the Medicines Regulations 1984 prohibits false or misleading statements in material supplied or displayed with a device. Together, these mean marketing vocabulary participates directly in the statutory characterisation of the product.

Insight 3: The device-medicine boundary is written in Schedule 1(a). Schedule 1(a) of the 2003 Regulations provides that a device that is also a medicine within s 3(1) of the Medicines Act 1981 is an exempt device, except where Schedule 2 cl 13(2) applies. The substance of the rule: where the drug component of a device plays only an ancillary role (typically drug-eluting stents or dressings with antimicrobial agents), the product is still handled as a device and must complete WAND notification; where the product itself constitutes a medicine, it goes onto the medicines track and the device notification duty does not apply. This is exactly the systemic implementation of the trailing words of s 3A(a), which allow the principal action to be assisted by those means.

Insight 4: Ordinary household consumer goods are not automatically out; the judgement turns on use, not channel. Some companies assume anything sold in a pharmacy is a device and anything sold in a supermarket is not; no such rule exists in New Zealand legislation. The judgement rests on the product’s intended purpose and mechanism, independent of sales channel. Conversely, some traditionally non-device categories, such as consumer electronics with measurement functions, need fresh characterisation once health claims are layered on.

4. Practical recommendations

• Maintain a claims inventory for every SKU. At project start GRZAN collects all external text, including packaging copy, instructions for use, website descriptions, e-commerce detail pages and distributor flyers, and compares each sentence against the six classes of s 4, marking every sentence that touches a therapeutic purpose. This step exposes more than 80% of characterisation risk in advance (the percentage is a practical estimate, not an official statistic).
• Record the s 4 and s 3A judgement as a two-part conclusion. A fixed format works well: conclusion one, whether a therapeutic purpose under s 4 exists, citing the applicable class; conclusion two, how the principal intended action is achieved and whether it falls within the s 3A(a) exclusion. GRZAN places both parts in the product characterisation statement for later review and reuse.
• Prepare written reasoning on component action for drug-device products. The interaction of Schedule 1(a) and Schedule 2 cl 13(2) requires explaining the ancillary position of the drug component in the overall action. Ask the manufacturer for a principal mechanism statement during development, avoiding last-minute document assembly at notification.
• Institute a regulatory review gate for claim changes. Any new health function statement must pass regulatory review before release. Reg 10 adds an independent requirement: an advertisement for a device must, where applicable, include an accurate description of the device, an explanation of its use, and appropriate warnings, precautions and any contra-indications.
• Re-run characterisation periodically. Product iterations, software upgrades and indication expansions can shift a product’s position. Re-run the s 4 and s 3A judgements annually and on major changes, filing results in the product dossier.

5. Verification checklist

• □ All external claim text has been collected and archived
• □ Every sentence has been compared against the 6 therapeutic purpose classes of s 4, with hits marked
• □ A two-part s 4 and s 3A characterisation conclusion has been recorded
• □ Drug-device products have obtained a principal mechanism statement, confirming whether Schedule 1(a) applies
• □ The mistaken approach of judging characterisation by channel rather than use has been ruled out
• □ A claims review workflow is live, covering new health function statements
• □ The Sponsor (New Zealand sponsor) understands the intended purpose commitment in reg 7(b)
• □ The characterisation file is included in an annual review plan
• □ A consistency cross-check against GMDN codes and risk classification is complete

How GRZAN can help. GRZAN provides medical device and IVD registration, quality system, authorised representative and local testing support for the New Zealand market. Our team manages Medsafe sponsor obligations and WAND entry requirements, and supports post-market vigilance obligations. Business enquiries: info@grzanglobal.com