The State Food and Drug Administration (SFDA) has sent a three-member team to investigate the medical injection suspected of killing up to four people.
Clindamycin phosphate glucose, used to treat bacterial infections, has been reportedly linked to four deaths, with 63-year-old Sun Xueying the latest possible victim to be identified.
The SFDA team is now at Anhui Huayuan Worldbest Biology Pharmacy Co, where the drug is produced, in East China's Anhui Province.
Liu Zilin, of the Anhui Provincial Food and Drug Administration, was quoted by The Beijing News on Monday as saying the investigation would last at least until the middle of August.
Liu also noted that most patients, mainly from rural areas, who suffered adverse reactions to the antibiotic, received injections at local clinics before being sent to hospital for emergency treatment.
More than 80 cases of severe adverse reactions to the drug, including the four possible deaths, have been reported in 10 provinces, according to the Adverse Drug Reaction Monitoring Centre of the SFDA.
The SFDA team is looking for proof of a link between the injections and the deaths
A Ministry of Health team has also been sent to No 2 Hospital Affiliated to Harbin Medical University, in Heilongjiang, where a 6-year-old girl died after using the drug.
More than 10 patients who had adverse reactions to the injections are receiving treatment at the hospital.
An increasing number of patients from Qinghai, Guangxi, Zhejiang, Heilongjiang and Shandong have complained about symptoms ranging from chest and stomach pain, diarrhoea, nausea, vomiting and even anaphylactic shock after being injected with the Anhui Huayuan drug.
Sun Xueying, from Xianyang, the drug's fourth possible victim, experienced a severe adverse reaction while receiving the injection to treat rheumatism on July 30, according to the Chinese Business View, a Shaanxi-based newspaper.
She died two days later due to multiple organ failure, including liver and kidney failure.
It was only when Sun's relatives read newspaper reports about the drug on August 4 that they began to suspect she might have been killed by it.
The Ministry of Health issued an urgent circular last week suspending use of the injection.
Of the 3.68 million bottles of clindamycin phosphate glucose it has produced since June, the Anhui company has sold 3.18 million units to 26 provinces, regions and municipalities. Some 1.4 million units have now been impounded.
Wang Xinchun, director of the emergency ward of the No 2 Hospital, said the hazardous drug was widely used in rural clinics because it was cheap.
Li Jun, director of the Heilongjiang Provincial Food and Drug Administration in Harbin, said the adverse reactions may also be a result of incorrect storage or use of the drug.
Source: China Daily,/em>