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: Management of bleeding irregularities among etonogestrel implant users: Is combined oral contraceptives pills or nonsteroidal anti-inflammatory drugs the better option? This study is to evaluate whether unacceptable bleeding among the etonogestrel implant user could be better alleviated using combined oral contraceptive pills (COCP) or nonsteroidal anti-inflammation drugs (NSAID). ### methods This is a prospective randomized study for evaluation of 84 etonogestrel implant (Implanon) users with prolonged or frequent bleeding. They were assigned to either receiving a COCP containing 20 mcg ethinyl estradiol/150 mg desogestrel for two continuous cycle or NSAID ; mefenamic acid 500 mg TDS for 5 days , 21 days apart for two cycles . Bleeding pattern during the treatment was recorded and analyzed. ### results A total of 32 women (76.2%) in COCP group and 15 women (35.7%) in NSAID group stop bleeding within 7 days after the initiation of treatment which was statistically significant (P < 0.05). The mean duration of bleeding and spotting days in women treated with COCP was significantly lesser compared to NSAID group (7.29 ± 3.16 vs 10.57 ± 4.14 days (P < 0.05). ### conclusion We conclude that COCP is more efficient compared to NSAID in managing bleeding irregularities among etonogestrel implant users.

sentence: They were assigned to either receiving a COCP containing 20 mcg ethinyl estradiol/150 mg desogestrel for two continuous cycle or NSAID ; mefenamic acid 500 mg TDS for 5 days , 21 days apart for two cycles .
[["ethinyl", "desogestrel", "POS"]]