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: Olmesartan Combined With Amlodipine on Oxidative Stress Parameters in Type 2 Diabetics, Compared With Single Therapies: A Randomized, Controlled, Clinical Trial.  To evaluate the effects of a fixed combination of olmesartan/amlodipine compared with olmesartan or amlodipine alone on some parameters of endothelial damage in diabetic , hypertensive patients .We enrolled 221 patients; 74 were randomized to olmesartan 20 mg, 72 to amlodipine 10 mg, and 75 to olmesartan/amlodipine fixed combination 20/5 mg for 12 months. We assessed blood pressure monthly; in addition, we also assessed at baseline, and after 6 and 12 months, the following parameters: lipoprotein (a), myeloperoxidase (MPO), isoprostanes, and paraoxonase-1 (PON-1). Blood pressure values obtained with fixed olmesartan/amlodipine combination were significantly lower than those reached with single monotherapies. There was a reduction of lipoprotein (a), and isoprostanes levels with olmesartan/amlodipine fixed combination, both compared with baseline, and with single monotherapies. On the other hand, there was an increase of PON-1 with fixed olmesartan/amlodipine combination, both compared with baseline, and with single drugs. All treatments reduced MPO compared with baseline; however, in group-to-group comparison, MPO reduction was greater with olmesartan/amlodipine fixed combination. Fixed combination of olmesartan/amlodipine was more effective than single monotherapies in reducing oxidative stress, especially in increasing PON-1, and reducing isoprostanes levels in diabetic and hypertensive patients.

sentence: To evaluate the effects of a fixed combination of olmesartan/amlodipine compared with olmesartan or amlodipine alone on some parameters of endothelial damage in diabetic , hypertensive patients .
[["olmesartan", "amlodipine", "POS"]]