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: Aspirin in the treatment of acute migraine attacks. Acetylsalicylic acid (aspirin or ASA) has been used for many years as an analgesic, antipyretic and anti-inflammatory drug. In recent years, evidence for its effectiveness in migraine headache has been demonstrated in several clinical trials. The effervescent highly buffered preparation of aspirin was shown to be effective, safe and well tolerated compared with placebo or other treatment options. The effervescent aspirin preparation is at least as effective as the combination of aspirin plus metoclopramide , but has fewer side effects . This review summarizes and analyzes clinical data of aspirin in the treatment of acute migraine attacks with respect to the different galenic formulations.

sentence: The effervescent aspirin preparation is at least as effective as the combination of aspirin plus metoclopramide , but has fewer side effects .
[["aspirin", "metoclopramide", "COMB"]]