Eliodoro Mercado

Eliodoro Donato Mercado (1866–1933), or Eliodoro Mercado y Donato,^[1] was a Filipino physician and army surgeon who, along with Victor Heiser, made a method of injecting chaulmoogra oil on treating leprosy.^[2] His work was published in 1914 titled, "Leprosy in the Philippines and its Treatment".^[3][4] He was considered as the "greatest leprologist of the Philippines" according to Zoilo M. Galang.^[5]

He was one of the famed graduates of the University of Santo Tomas at the time when the university first opened its medical course since 1871.^[6]

Mercado served at the San Juan de Dios Hospital in 1885 where he dealt with cholera cases.^[7] At the time he was a medical student during the 1882 cholera epidemic in Manila, Mercado described that people would avoid Calle Cervantes and San Lazaro estate due to the unbearable stench of decaying bodies.^[8][7] He also became a resident physician in the Leper Department at San Lazaro Hospital.^[3][4]

He was also founding member of Colegio Médico-Farmacéutico of the Philippines and ex-supernumerary surgeon in the Spanish Army.^[4][3]

Victor Heiser who was Chief Quarantine Officer and Director of Health for the Philppine Islands at the time visited the Louisiana Leprosy Home. There, he gained a favourable impression of using chaulmoogra oil for leprosy patients and learned better techniques on how to administer the oil orally from Ralph Hopkins and Isadore Dyer.^[2]

Mercado, who was in immediate charge as a physician at the San Lazaro Hospital in Manila, helped Heiser to give a thorough trial for the oil on leprosy patients.^[2][1] The new method was initiated at the hospital in 1909. The results were successful but oral administration gave patients nausea and resistance for taking the drug. Physicians at the hospital also tried using hypodermic injection but did not satisfactorily absorbed the oil.^[2]

Later, both Heiser and Mercado made a camphor-resorcin solution of chaulmoogra oil. Results were positive as the solution was readily absorbed.^[2] After the first case was treated, Heiser wrote in his autobiography:^[2]

Few can imagine with what a thrill we watched the first case to which chaulmoogra was administered in hypodermic form, how we watched for the first faint suspicion of eyebrows beginning to grow in again and sensation returning to paralyzed areas.

In 1913, Heiser published the first two cases under the Public Health Reports. According to his publication, leprosy bacilli was no longer found using clinical microscopical examination on two patients.^[2] As for Mercado, his findings were published in 1914 and presented before the Second Regional Assembly of Filipino physicians and pharmacists.^[3]

The "Mercado mixture", named after him, was a treatment for leprosy first developed in the Philippines. It is composed of 60 cubic centimetres of chaulmoogra oil and camphorated oil and 4 grams of resorcin. While initially showing promise with a high recovery rate according to Heiser in 1914, many patients experienced relapses. Later reports indicated some improvement or arrest of the disease, but the method was painful and not considered a cure. Nevertheless, the mixture was considered a milestone on further studies about the therapeutic effects of chaulmoogra oil.^[9]