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: [Current and future aspects of intravenous thrombolysis for acute stroke]. Intravenous thrombolysis using alteplase was approved for clinical use for acute ischemic stroke treatment in Japan in 2005, on the basis of the results of a domestic clinical trial, Japan alteplase Clinical Trial. This therapeutic strategy has become the standard strategy during the following 8 years. However, this therapy still has room for improvement. One of the important drawbacks of intravenous thrombolysis is the limited therapeutic time window. On the basis of the results of the European Cooperative Acute Stroke Study III and the pooled analysis, the current time window is within 4.5 h of stroke onset. The window may be extended to 6 h or longer, probably by appropriate determination of the eligibility of a patient for receiving therapy by using penumbral imaging techniques, such as diffusion-weighted imaging (DWI)/perfusion-weighted imaging mismatch and DWI/magnetic resonance imaging mismatch. Newer-generation recombinant tissue-type plasminogen activators , such as desmoteplase and tenecteplase , will also help extend the time window . Patients with wake-up and unclear-onset strokes are generally ineligible for thrombolysis; therefore, the optimal therapeutic strategy for such patients should be established. Another important drawback is acute stroke therapy paralleling or following intravenous thrombolysis. Mechanical recanalization by endovascular therapy, antithrombotic therapy, neuroprotective therapy (e.g., using intravenous free radical scavenger), and sonothrombolysis are promising candidates for combined use with intravenous thrombolysis.

sentence: Newer-generation recombinant tissue-type plasminogen activators , such as desmoteplase and tenecteplase , will also help extend the time window .
[]