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: The role of brain norepinephrine in clonidine suppression of isolation-induced distress in the domestic chick. Distress vocalizations (DV) induced by social isolation were measured in 1-day-old domestic chicks after intracerebroventricular injections of drugs believed to exert their effects through the noradrenergic system. The alpha-adrenoreceptor agonist clonidine reliably suppressed DV rates at doses low as 0.08 micrograms. When given alone, phentolamine, phenoxybenzamine, propranolol, sotalol, and yohimbine (adrenoreceptor antagonists) did not reliably alter DV rates at doses that were not toxic. The clonidine DV suppression was reliably reversed by yohimbine ( 1.75 micrograms ) , but by none of the other adrenoceptor antagonists or naloxone . 6-Hydroxydopamine at doses as high as 120 micrograms, which essentially eliminated forebrain norepinephrine, failed to suppress DV rates reliably when given alone and, when given in combination with clonidine (0.1 micrograms) or morphine (0.05 micrograms), failed to reverse the severe DV suppression imposed by these drugs. The results suggest that clonidine suppresses DV rates in or by some means other than prejunctional alpha 2-adrenoreceptor stimulation.

sentence: The clonidine DV suppression was reliably reversed by yohimbine ( 1.75 micrograms ) , but by none of the other adrenoceptor antagonists or naloxone .
[]