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: Triple therapy with ranitidine or lansoprazole in the treatment of Helicobacter pylori-associated duodenal ulcer . The aim of this study was to verify the efficacy--in the cure of duodenal ulcer associated H. pylori infection--of ranitidine 300 mg taken late in the evening or lansoprazole 30 mg taken before breakfast, coupled with clarithromycin and metronidazole. ### methods Eighty patients with endoscopically proven active duodenal ulcer were randomized to take ranitidine or lansoprazole for 4-8 wk, together with clarithromycin 250 mg b.i.d. and metronidazole 500 mg b.id. for the first 2 wk. Endoscopic controls, as well as histological and urease tests for H. pylori, were performed at entry and after 4 and 8 wk. ### results According to intent-to-treat analysis, ulcers were healed after 4 wk in 36/40 patients (90%) with ranitidine and in 38/40 (95%) with lansoprazole. After 8 wk, the healing percentage with ranitidine and lansoprazole was 97% (39/40) and 95% (38/40), respectively. H. pylori was eradicated in 85% of the patients taking ranitidine and in 90% of those taking lanzoprazole. Side effects were reported in 25% of the patients in both groups. ### conclusions Our results confirm that the combination of ranitidine, clarithromycin, and metronidazole can be considered an alternative to proton pump inhibitors in terms of clinical efficacy and economy.

sentence: Triple therapy with ranitidine or lansoprazole in the treatment of Helicobacter pylori-associated duodenal ulcer .
[]