The article by Dr. Lighthizer (“ How to Rx the Lowest Cost Drug for Your Patient,” February 2014) was both interesting and informative, but plain misleading. It did not address product performance, manufacturing, professional liability, or concerns about counterfeit products. We feel this article was well intended but does nothing for the patient or the doctor in management. It gives the insurance companies a stronger argument under a false pretense that generic agents are lower in cost and equal in treatment to brand drugs, thus dictating to the physician what he or she can prescribe.

The US Supreme Court has made legal opinions that exempt generic drug manufacturers from liability. A 2011 decision by the US Supreme Court was based on the premise that generic products are identical to brand-name products approved by the FDA. This ruling made generic drug manufacturers not liable for not warning clinicians of safety risks associated with the use of the generic product._¹

A second opinion came in June 2013 when the US Supreme Court overturned a lower New Hampshire jury that awarded monetary damages to a patient harmed by a generic medication. In this case, the Supreme Court stated that the generic manufacturer had no liability because the FDA had approved the innovator product and the generic medication had provided safety information based on the brand-name product._² In the event that the product fails to perform in such a case, who would be liable?

In manufacturing, the chemistry of the innovator or brand product is strictly controlled in the production process, but not so for the generic version. Generic manufacturers are allowed a wider margin of formulation, with acceptable analytical variations typically of 5% of the innovator product, plus variations in inactive ingredients. Often, different manufacturers use their own formulations. This detail makes generics less consistent in therapeutic benefit, safety and effectiveness. The discrepancies can be such that when comparing generic latanoprost to brand-name Xalatan, the average IOP reduction of the generic counterpart was 25% while Xalatan’s reduction was 38%, with much fewer adverse events._³

Lastly, with the access to foreign pharmacy suppliers, the issue of counterfeit medications is one of concern. In 2012, for example, the FDA warned surgeons of the dangers of counterfeit Avastin._⁴

As clinicians, we are held accountable for both diagnostic and therapeutic outcomes of our patients. Without head-to-head studies, it is difficult to ascertain clinical outcomes of safety and efficacy of generic drugs. Unlike systemic medications, it is also difficult to evaluate therapeutic levels of medications in the eye. To the discerning clinician, clinical trials make safety and efficacy data valuable as it guarantees patient safety and clinical outcomes.

With the long history of topical ophthalmic medication failing to perform and new legal implications, it is important that we are both aware and discuss these issues with our patients. Failure to do so is bad medicine.

—Agustin L. Gonzalez, OD, Dallas
Mel Freidman, OD, Memphis, Tenn.

1. Hovanesian JA. Can we afford to make generic substitutions? Ocular Surgery News. March 29, 2012. Available at: www.healio.com/ophthalmology/blogs/hovanesian/can-we-afford-to-make-generic-substitutions. Accessed Feb. 25, 2014.
2. Thomas K. In 5-4 Ruling, Justices Say Generic Makers Are Not Liable for Design of Drugs. The New York Times. June 24, 2013. Available at: www.nytimes.com/2013/06/25/business/justices-rule-generic-makers-not-liable-for-drugs-design.html. Accessed April 3, 2014.
3. Narayanaswamy A, Neog A, Baskaran M, et al. A randomized, crossover, open label pilot study to evaluate the efficacy and safety of Xalatan in comparison with generic Latanoprost (Latoprost) in subjects with primary open angle glaucoma or ocular hypertension. Indian J Ophthalmol. 2007 Mar-Apr;55(2):127-31.
4. US FDA website. Counterfeit Version of Avastin in U.S. Distribution. Feb. 14, 2012. Available at: www.fda.gov/Drugs/DrugSafety/ucm291960.htm. Accessed Feb. 25, 2014.

Dr. Lighthizer responds:
The purpose of the article was to provide doctors an avenue to access potential resources that could allow less expensive medication options for patients, including both generics and cheaper brand names if possible.  I was not advocating that all prescribing should be generic, nor should it go the other way and be entirely brand name. 

Simply put, many patients have compliance issues and cost is a major factor in that. It was my hope that the article informed doctors of potential resources to research in order to perhaps find a cheaper option for certain patients.