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: [ Intraoperative anaphylactic shock induced by methylergometrine and oxytocin ] . We report a case of intraoperative anaphylactic shock in a 32-year-old multigravida woman undergoing elective cesarean section for partial placenta previa. Anesthesia was performed using combined spinal and epidural technique. After the baby was born, methylergometrine was administered i.v. simultaneously with oxytocin, the latter injected directly into the uterine muscle by an obstetrician. Several minutes later, she presented with dyspnea and became agitated. Because of the potential risk of pulmonary embolism, the patient was immediately intubated and mechanical ventilation was started. Her systolic blood pressure decreased to 50 mmHg and SpO2 to 87% under 100% oxygen administration. After catecholamine infusion, however, her respiratory condition soon improved. Postoperatively, her conjunctiva and vulva were not edematous. From the clinical course, it was considered that the patient was very likely to have suffered an anaphylactic reaction to oxytocin or methylergometrine. Forty days later, serological examinations as well as skin tests for those two drugs were carried out. While the serological tests were negative, the skin tests indicated the patient was allergic to both drugs. It is concluded that the endogenous peptide oxytocin can induce anaphylactic shock in multiparous women.

sentence: [ Intraoperative anaphylactic shock induced by methylergometrine and oxytocin ] .
[["methylergometrine", "oxytocin", "COMB"]]