Pharmaceutical marks require lesser degree of confusion

Madras High Court in a dispute between two entities in the pharmaceutical industry restrains use of a deceptively similar mark. The Plaintiff, Sun Pharmaceuticals Limited (Sun Pharma) filed the suit against the Defendant, Kivi Labs Ltd (Kivi Labs) alleging trademark infringement, passing off, damages, etc,. Sun Pharma relying on its rights in the registered mark AMIXIDE seeks to permanently restrain Kivi Labs from using the mark KIMIXIDE. Both parties sell anti-depressant drugs under their respective trademarks.

Sun Pharma in the suit contends:

  1. They are a globally reputed pharmaceutical company. They adopted and commenced use of the mark AMIXIDE in April 1984 in respect of pharmaceutical preparations for treatment of depressive and psychotic disorders.
  2. The AMIXIDE mark is registered in India in Class 5 since the year 2008. On account of long and extensive use the mark has garnered goodwill and reputation and the trade and public associate the mark exclusively with them.
  3. Sun Pharma became aware of the use of the mark KIMIXIDE by Kivi Labs when it was published in the trademark journal. Thay have opposed the KIMIXIDE mark, and the opposition proceedings are ongoing before the Trademark Registry.
  4. Adoption of a deceptively similar mark KIMIXIDE amounts to trademark infringement and passing off. The confusion and deception among the trade and public will be intensified considering that the products have similar compositions and is used to treat the same ailments. The cease-and-desist letter was not complied with by Kivi Labs.

Kivi Labs defended the suit raising the following contentions:

  1. They honestly adopted the mark KIMIXIDE for products containing Chlordiazepoxide and Amitriptyline. They derived the mark by taking ‘Ki’ from Kivi and ‘Mixide’ from the ingredient names. Such adoption is in line with common practise in the pharmaceutical industry. Both the products will be sold only prescription and there will be no confusion.
  2. They are using the mark KIMIXIDE since 2002 and they are an honest concurrent user of the mark. There is no evidence to prove Sun Pharma’s claim of use of the mark AMIXIDE since 1984.
  3. Sun Pharma was aware of the use of the mark KIMIXIDE by Kivi Labs since 2002. The longstanding use of the KIMIXIDE mark eliminates any potential for confusion or deception.
  4. There is delay in filing the suit and acquiescence on the part of Sun Pharma.

Court Ruling

Further to the completion of the pleadings, Court framed issues. Both sides did not adduce oral evidence and relied on documents to substantiate their case. The Court after considering the pleadings, documents, arguments and case laws held:

  1. The rival marks AMIXIDE and KIMIXIDE are both anti-depression medications and schedule – H drugs. It is judicially settled that the burden of proving trademark infringement is lighter in the case of medicinal drugs, more particularly Schedule – H drugs.
  2. The likelihood of confusion or deception is the crucial factor in cases of trademark infringement and passing off. Several parameters are considered in assessing this likelihood, including the goods and services involved, the type of consumers, and the trade channels. Deceptive similarity is determined based on visual, phonetic, and structural resemblances between the marks.
  3. From the pleadings and the documents on record, in the instant case Sun Pharma is the prior user of the mark AMIXIDE. The rival products ‘AMIXIDE’ and ‘KIMIXIDE,’ are anti-depression drugs and classified as Schedule-H drugs. Sun Pharma’s sales turnover for the AMIXIDE product also far exceeds that of KIMIXIDE.
  4. Sun Pharma has coined the trademark ‘AMIXIDE’ by taking three letters from ‘Amitriptyline’ and the last four letters from ‘Chlordiazepoxide’. Kivi Labs contention that they adopted the mark KIMIXIDE by taking ‘Ki’ from the trade name Kivi is not convincing considering that they are using the prefix ‘Kivi’ in other marks.
  5. Kivi Labs cannot justify their adoption by picking and choosing from Sun Pharma’s prior adopted, used and registered mark AMIXIDE. Considering that the AMIXIDE mark has acquired a distinct identity and goodwill, adoption of a deceptively similar mark KIMIXIDE in relation to identical goods amounts to infringement and passing off.
  6. The test for passing off considers the potential for confusion among the trade and public with average intelligence and imperfect recollection. The argument that the rival products are Schedule -H drugs sold only on medical prescription will not succeed. The marks AMIXIDE and KIMIXIDE are phonetically similar to pose a risk of confusion more so in handwritten prescriptions. Such confusion can lead to disastrous consequences.
  7. Kivi Labs argument regarding honest concurrent use ought to fail. They have not let in any oral and documentary evidence to prove honesty in adoption of a deceptively similar mark in relation to identical products.
  8. Sun Pharma has successfully established trademark infringement on the triple identity test. Kivi Labs use of the mark KIMIXIDE amounts to infringement on account of it deceptively similar nature to AMIXIDE mark in relation to identical goods having identical trade channels.
  9. The defence of acquiescence set up by Kivi Labs also ought to be rejected as there is no oral or documentary evidence to support such contention.

Considering the above findings the Court decreed the suit in favour of Sun Pharma permanently restraining Kivi Labs from using the mark KIMIXIDE.


The Court order reaffirms that the onus is on the person arguing honest adoption to prove his case. The defendant in this case did not lead any oral or documentary evidence to prove its honesty in adoption. Therefore, the court drew an adverse inference as the marks were held to deceptively similar and were used as ant-depressant drugs.

Please follow and like us: