Drug Availability and Quality

Drug availability and quality concerns whether the medicines a health system needs are reliably present where and when they are required, are affordable to those who need them, and are of assured quality. Access to safe, effective and quality-assured medical products is one of the building blocks of a functioning health system, and failures in availability or quality undermine the value of every other part of the system.

Definition

Drug availability refers to whether needed medicines and medical products are reliably accessible and affordable within a health system; drug quality refers to whether those products meet required standards of identity, strength, purity and safety, as opposed to being substandard (failing specifications) or falsified (deliberately misrepresented).

Scope

The topic covers the availability and affordability of essential medicines, the supply systems that deliver them, and the quality dimension — the threat posed by substandard and falsified products and the regulatory functions that guard against them. It is treated as a reference framework for understanding medicines as a health-system component, and contains no dosing, prescribing or individualized treatment information.

Core questions

• Are needed essential medicines reliably available and affordable to those who require them?
• What supply-system and pricing factors determine medicine access?
• How common are substandard and falsified medicines, and what harm do they cause?
• How do regulatory systems assure the quality of medical products?

Key concepts

• Essential medicines
• Medicine availability and affordability
• Supply chain and stock-outs
• Substandard medicines
• Falsified medicines
• Medicines regulation and quality assurance
• Generic medicines pricing

Key theories

Essential medicines as a system building block

WHO frames access to essential medical products — equitably available, of assured quality and safety, and used in a cost-effective way — as one of the six health-system building blocks, supported by the concept of an essential medicines list that prioritizes products meeting priority health needs.

Mechanisms

Reliable medicine access depends on a chain that selects, procures, finances, distributes and dispenses products, and that protects their quality along the way. Cameron and colleagues show that availability and affordability vary widely and are shaped by prices, the public-private divide and the use of generics, so that essential medicines are often poorly available in the public sector and expensive in the private sector. Quality depends on regulatory oversight: where regulation and supply systems are weak, substandard products that fail specifications and falsified products that misrepresent their identity can enter the chain. Ozawa and colleagues estimate that such products are common in low- and middle-income countries, where they waste resources and can cause direct harm, including treatment failure and contribution to antimicrobial resistance.

Clinical relevance

The availability, affordability and quality of medicines determine whether effective treatments can actually be obtained and trusted; substandard or falsified products can lead to treatment failure and harm at a population level. This entry describes medicines as a system-level component for reference and education and provides no dosing, prescribing or individualized treatment guidance.

Epidemiology

Surveys across many low- and middle-income countries document low public-sector availability and high private-sector prices for essential medicines, leaving many treatments unaffordable. A systematic review and meta-analysis estimated that a substantial share of medicines sampled in these settings were substandard or falsified, representing a large economic burden and a threat to health.

Evidence & guidelines

The WHO Model List of Essential Medicines and the building-blocks framework provide the principal reference standards for what a system should ensure regarding access to quality-assured medical products. These are policy and normative reference documents, not individualized clinical prescribing guidance.

History

The WHO Model List of Essential Medicines, first issued in 1977, established the principle of prioritizing a limited set of medicines to meet priority health needs. Subsequent measurement work in the 2000s quantified poor availability and affordability across many countries, and growing recognition of substandard and falsified products led to coordinated surveillance and regulatory attention, with major evidence syntheses appearing in the 2010s.

Debates

How should medicine prices and the role of generics be managed?

Promoting quality-assured generics can greatly improve affordability, but achieving low prices while sustaining reliable supply and quality, and balancing public versus private provision, remains a contested policy problem.

How large is the substandard and falsified medicines problem?

Estimates of prevalence vary with sampling and detection methods, and improving surveillance and regulatory capacity to measure and curb the problem is an ongoing challenge, especially in settings with weak oversight.

Key figures

• Richard Laing
• Sachiko Ozawa
• Alexandra Cameron

Seminal works

• who-essential-medicines
• cameron-2009
• ozawa-2018

Frequently asked questions

What are essential medicines?

Essential medicines are those that satisfy the priority health-care needs of a population. The WHO Model List identifies them so that systems can prioritize ensuring their availability, affordability and quality, and they are intended to be available at all times in adequate amounts.

What is the difference between substandard and falsified medicines?

Substandard medicines are authorized products that fail to meet quality standards or specifications, whereas falsified medicines deliberately misrepresent their identity, composition or source. Both can cause harm and are more common where regulation and supply systems are weak.