You will be shown a paragraph from a biomedical research article. Your task is to extract all drug combinations appearing in a specific sentence within in the paragraph. Each drug combination should be assigned to one of the following three categories:

- POS: Indicates a positive interaction between the drugs in the combination; for instance, drugs that have an additive or synergistic effect.
- NEG: Indicates a negative interaction between the drugs in the combination; for instance, combining these drugs might result in adverse side effects, or might reduce their efficacy.
- COMB: Indicates that the drugs are given in combination, but the type of interaction between the drugs cannot be determined based on the provided context.

Please format your answer as a json array. Each entry in the array should itself be an array formatted as [<drug_1>, <drug_2>, ..., <drug_n>, <category>] where <category> is one of the three categories listed above and <drug_1>, ..., <drug_n> are drug names copied verbatim from the input sentence. Different combinations may involve different numbers of drugs; in other words, the `n` in <drug_n> may vary.

As an example, the following output describes two extracted drug combinations; one between two drugs, and one between three drugs:

[["artesunate", "artemether", "COMB"], ["Nifedipine", "Labetalol", "Prazosin", "POS"]]

The paragraph and specific sentence are below. You should only extract relationships expressed in the specific sentence; the paragraph is provided for context.

In your output, return only the json array and no other text. If no drug combinations appear, return an empty array `[]`.

paragraph: Prescription pattern in the department of surgery in a tribal district hospital of andhra pradesh, India. Usually, surgical management cannot be completed without the use of antimicrobial and analgesic drugs. Irrational prescription may lead to severe postoperative complications. ### aim The objective of this study was to evaluate the prescription trend in the surgery department of a tribal district hospital so as to determine the extent of rational use of medicines. ### Materials And Methods It was a retrospective study in which 50 cases were selected randomly. Case records were analyzed for prescription trend. Data was analyzed using Microsoft Office Excel 2007 and values were presented descriptively. ### results Most of the cases were between the age group of 21 and 40 years, 18 cases (36%). Commonest cause of hospitalization was renal calculi (10 (20%)) followed by acute abdomen and abscess (6, (12%)). Total of 255 numbers of drugs were used with an average of 5.1 drugs per patient. Most preferred route was intravenous route (174 drugs, 68.2%). Antimicrobial was the most common (97 (38.0%)) group of drugs followed by analgesic/antipyretics (50 (19.6%)). Among antimicrobials , ciprofloxacin ( 22 ( 22.7 % ) ) was the most common drug followed by metronidazole ( 21 ( 18.5 % ) ) . All the cases were managed by empirical treatment. Two different antimicrobials were prescribed to 20 (40%) of cases. Dosage of 83 (32.6%) drugs was inappropriate while frequency was inappropriate in 26 (10.2%) cases. ### conclusion Urgent steps like specific guidelines, training, and monitoring of drugs use are needed to correct some irrational approaches.

sentence: Among antimicrobials , ciprofloxacin ( 22 ( 22.7 % ) ) was the most common drug followed by metronidazole ( 21 ( 18.5 % ) ) .
[]