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 Table of Contents  
REVIEW ARTICLE
Year : 2017  |  Volume : 55  |  Issue : 3  |  Page : 220-222

Generic drugs in ophthalmic practice: Boon or bane?


Deparment of Ophthalmology, Sundaram Medical Foundation, Shanthi Colony, Chennai, India

Date of Web Publication9-Mar-2018

Correspondence Address:
Dr. Murali Ariga
M. N. Eye Hospital Private Limited, Chennai, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/tjosr.tjosr_34_17

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  Abstract 


Generic pharma products are inexpensive as compared to the original innovator branded drugs. True generics are not freely available in India. There have been concerns about efficacy and quality of generics that are available. This review outlines these issues and the legislation regarding the availability and use of generics in our practice.

Keywords: Generics, branded generics, innovator brands, efficacy, cost effectiveness


How to cite this article:
Ariga M, Rajalakshmi M, Praveena C. Generic drugs in ophthalmic practice: Boon or bane?. TNOA J Ophthalmic Sci Res 2017;55:220-2

How to cite this URL:
Ariga M, Rajalakshmi M, Praveena C. Generic drugs in ophthalmic practice: Boon or bane?. TNOA J Ophthalmic Sci Res [serial online] 2017 [cited 2018 Dec 15];55:220-2. Available from: http://www.tnoajosr.com/text.asp?2017/55/3/220/226866




  Introduction Top


A generic drug is a pharmaceutical product, usually intended to be interchangeable with an innovator product that is manufactured without a licence from the innovator company and marketed after the expiry date of the patent or other exclusive rights. For instance, Xalatan (originally made by Pharmacia and now marketed by Pfizer) is the original research product containing Latanoprost. Generics should be identical in dose, strength, route of administration, safety, efficacy, and intended use. The Food and Drug Administration of USA (FDA) requires the bioequivalence of the generic product to be at least 80% of that of the innovator product.

When generic products become available, the market competition often leads to substantially lower prices for both the original brand name product and the generic forms. The time it takes a generic drug to appear on the market varies. The patient protection and affordable care act allow the FDA to approve generic versions of drugs and grant manufacturers 12 years of exclusive use before generics can be developed.

In India, there is very few true generic topical glaucoma medication that is available at local pharmacies. Most of the available drugs are either the multinational company original brands (MNC) or generic brands.

Generic brands are sold as a lesser-known brand name which may not be aggressively advertised or marketed. They are identified more by product characteristics and may be manufactured by less prominent companies, or manufactured on the same production line as a “named” brand. Generic brands are usually less expensive than the original brands. For example, Lumigan is the original brand name of Bimatoprost manufactured and marketed by Allergan worldwide, but Bimatoprost is also sold as Careprost by Sun pharma and Bimat LS by Ajanta Pharma in India. Similarly, Travatan made by Alcon is the international brand name of Travoprost while Travaxo/Travo are Indian generic brands.


  Why Are Generics Less Expensive Top


Generic drugs can save patients substantial costs.[1] The main reason for the relatively low price of generic medicines is that competition increases among producers when drugs are no longer are protected by patents. Companies incur fewer costs in creating the generic drug and are therefore able to maintain profitability at a lower cost to consumers. The costs of these generic drugs are so low that many developing countries can easily afford them. For example, Thailand has imported millions of doses of a generic version of the drug Plavix (blood-thinning drug used to help prevent heart attacks), at the cost of 3 US cents per dose. Cipla has done the same for drugs used in AIDS management in Africa.

Generic manufacturers do not incur the cost of drug discovery and instead can reverse-engineer known drug compounds to allow them to manufacture bioequivalent versions. Generic manufacturers also do not bear the burden of proving the safety and efficacy of the drugs through clinical trials since these trials have already been conducted by the brand name company. The average cost to brand-name drug companies of discovering and testing a new innovative drug (with a new chemical entity) may be millions of dollars.

Generic drug companies also receive the benefit of the previous marketing efforts of the brand-name drug company. Many of the drugs introduced by generic manufacturers have already been on the market for a decade or more and may already be well-known to patients and providers. As long as a drug patent lasts, a brand name company enjoys a period of “market exclusivity” or monopoly, in which the company can set the price of the drug at a level which maximizes profitability. This price often greatly exceeds the production costs of the drug, which can enable the drug company to make a significant profit on their investment in research and development, thus enabling them to fund the research and development of new medicines which most generic companies cannot afford to do. The advantage of generic drugs to consumers comes in the introduction of competition, which prevents any single company from dictating the overall market price of the drug.

Generic drugs can be legally produced for drugs where as follows:

  1. The patent has expired
  2. The generic company certifies the brand company's patents are either invalid, unenforceable or will not be infringed
  3. The drugs which have never held patents
  4. In countries where a patent (s) is/are not in force.


Brand-name drug companies have used a number of strategies to extend the period of market exclusivity on their drugs and prevent generic competition. Patents are typically issued on novel pharmacological compounds quite early in the drug development process, at which time the “clock” to patent expiration begins ticking. Later in the process, drug companies may seek new patents on the production of specific forms of these compounds, such as single enantiomers of drugs which can exist in both “left-handed” and “right-handed” forms, different inactive components in a drug salt, or a specific hydrate form of the drug salt. If granted these patents “reset the clock” on patent expiration. This kind of patents may be contested by generic drug manufacturers as being invalid.

Large pharmaceutical companies often spend millions of dollars protecting their patents from generic competition. Apart from litigation, companies use other methods such as reformulation or licensing a subsidiary (or another company) to sell generics under the original patent. Generics sold under license from the patent holder are known as authorized generics – for example, Dr. Reddy's Laboratories markets an authorized generic version of simvastatin under license from Merck and Co., and even show Merck as the actual manufacturer and have Merck's logo on the bottom.


  Glaucoma Medication in India Top


Currently, there are five major classes of medications that are used to lower the intraocular pressure (IOP): beta-adrenergic antagonists, adrenergic agonists, parasympathomimetics, prostaglandin analogs, and carbonic anhydrase inhibitors.

Today in India, one has free access to topical glaucoma medication to the extent that one would be able to obtain any brand or type of glaucoma medication sometimes even without a doctor's prescription.[3] Prices vary across the MNC brands for the different classes of medication. True generic medication (sold only by pharmacological names such as Timolol or Latanoprost) is not freely available, but only Generic brands of various Indian companies (Sun pharma, Cipla, Microvision, Ajanja, Intas etc.) are freely available.

Prostaglandin analogs are fast becoming the mainstay of therapy for subjects with glaucoma. While generic latanoprost may be chemically equivalent to Xalatan ®, there was no available information on their therapeutic or clinical equivalence. A pilot study [2] was performed to compare the efficacy and tolerability of Xalatan ® with generic latanoprost in subjects with primary open-angle glaucoma or ocular hypertension.[2]

This was a randomized, crossover, open-label pilot study to evaluate the efficacy and safety of Xalatan ® in comparison with generic brand latanoprost (Latoprost). Results showed that Xalatan ® reduced the IOP significantly more than Latoprost at the end of week 12. It was also noted that there was a further decrease in IOP when subjects receiving Latoprost were crossed over to Xalatan® and increase in IOP when subjects receiving Xalatan ® were crossed over to Latoprost.

Chemical analysis of samples has revealed that as compared to Xalatan ®, Latoprost has higher levels of particulate matter, which could potentially cause greater ocular irritation.[3] Since latanoprost is a prodrug, the higher pH of Latoprost could also potentially affect stability as well as release of active drug in the eye. This may possibly explain the higher incidence of ocular irritation seen in the group receiving generic latanoprost as compared to the group receiving Xalatan ®.

Study limitations – the small number of patients and unequal numbers of subjects in the two groups is the limitation of the study. Since there was no washout period, limited inferences could be drawn on the safety and tolerability especially in the second phase.

In another study in North America, Kahook et al.[4] found that generic latanoprost formulations had significant loss of active ingredient concentration after exposure to 25°C and 50°C for 30 days and bottles of generic medications had higher levels of particulate matter compared to brand name versions.[4]


  Other Concerns About Generics Top


Concerns about ophthalmic medication not being therapeutically equivalent have been raised in the past. It has been reported that three of the five brands of generic Ciprofloxacin eye drops that were tested had a significant proportion of suboptimal drug concentration. Studies in the past have demonstrated nonequivalence of the generic drug with the branded prednisolone, diclofenac sodium ophthalmic solution, and ketorolac. Use of generic diclofenac was associated with high incidence of corneal melting and superficial punctate keratopathy. Similar concerns have been raised with use of generic versions of timolol gel-forming solution. There is no original brand of timolol gel in India, but Glucomol OD and Timolet GFS were available till recently. Both have now been withdrawn.

Retention time on the ocular surface, pH, inactive ingredients and preservative concentrations differed between the branded and generic versions. Many physicians are not comfortable in allowing their patients to take the branded generic equivalent agents and in many countries the pharmacist may not substitute brand names if a doctor has written the prescription out using a brand name and ticked the box on the prescription marked “Brand substitution not permitted.”

There are many counterfeit medicines and drugs whose expiry date has passed which are still for sale on the market, posing as both generic and proprietary brands. The counterfeits may be less effective than the real drug or may have no active ingredients at all. This is a particular problem in areas poor supervision of the pharmaceutical sector, which often also has many patients with low incomes and illiteracy. Medicines bought over the Internet are also often found to be counterfeit. This can make saving on prescription costs risky.


  Price Control Top


The cost of glaucoma medication is an important barrier to continued use of the medication which is essential for IOP control. In a survey conducted on 243 glaucoma patients who were on at least one glaucoma medication in an eye clinic in Southern India, it was found that 21.8% of patients reported problems in paying for their glaucoma medications.[1]

Governments want to promote the use of unbranded generic medicines – they are inexpensive compared to branded drugs. At a recent meeting of the pharmaceutical advisory committee in India, it was decided that there should be a cap on the prices of drugs. Drug control means that a particular class of drug should not exceed the price specified by the Drug controller, for example, lubricants, topical steroids, and steroid-antibiotic combinations manufactured and sold in India come under this category now and cannot be sold beyond the stipulated price (most of these steroids are used postoperatively after cataract surgery which is the most cause for blindness in India. Glaucoma is another common cause for blindness, and topical medication is the mainstay of management – it is, therefore, it may be useful to have a cap on prices for commonly used glaucoma medication too.


  Jan Aushadi Stores Top


The Government of India has championed setting up Jan Aushadhis, which are pharmacies selling only generic name medicines to the extent possible, giving preference to pharmaceutical public sector undertakings too. There are not enough Jan Aushadhis, possibly <3000 against the more than 8 lakh retail pharmacies in existence, with many rural areas still underserved. To facilitate Jan Aushadhis, the Drugs Technical Advisory Board (DTAB) in May 2016 considered amending Rule 65 (11A) of the Drugs and Cosmetics Act, 1940 so that pharmacists can dispense generic name medicines and/or equivalent brands against prescriptions in brand names. The DTAB rejected the idea citing that the bioavailability of a generic drug may not be as good as that of the prescribed brand.


  Conclusion Top


There is now a wide variety of glaucoma medication available in India including MNC and generic brands. By and large, most practitioners use both these types of medication in their practice as cost is a significant consideration,[5] particularly with prostaglandins.[5] Available studies comparing efficacy and cost-effectiveness among medication available in India have many limitations. Generic brands are here to stay and have a definite role in glaucoma management in India. True generics may become available for all medication at conveniently located Jan Aushadi stores in railway stations and bus stations. One has to balance cost, efficacy, availability of drugs, and clinical judgment and then consider their use in his or her practice milieu.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Sleath BL, Krishnadas R, Cho M, Robin AL, Mehta R, Covert D, et al. Patient-reported barriers to glaucoma medication access, use, and adherence in Southern India. Indian J Ophthalmol 2009;57:63-8.  Back to cited text no. 1
[PUBMED]  [Full text]  
2.
Narayanaswamy A, Neog A, Baskaran M, George R, Lingam V, Desai C, 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;55:127-31.  Back to cited text no. 2
[PUBMED]  [Full text]  
3.
Ariga M, Rajalakshmi M, Nivean M, Ramyaa V. The Chennai glaucoma drops study. Int J Pharmacol Biosci 2017;8:238-249.  Back to cited text no. 3
    
4.
Kahook MY, Fechtner RD, Katz LJ, Noecker RJ, Ammar DA. A comparison of active ingredients and preservatives between brand name and generic topical glaucoma medications using liquid chromatography-tandem mass spectrometry. Curr Eye Res 2012;37:101-8.  Back to cited text no. 4
[PUBMED]    
5.
Chambers WA. Ophthalmic generics – Are they really the same? Ophthalmology 2012;119:1095-6.  Back to cited text no. 5
[PUBMED]    




 

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  In this article
Abstract
Introduction
Why Are Generics...
Glaucoma Medicat...
Other Concerns A...
Price Control
Jan Aushadi Stores
Conclusion
References

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