flask-debugtoolbar ImportError: No module named flask_debugtoolbar

I've done pip install flask-debugtoolbar but im still getting an import error

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_debugtoolbar import DebugToolbarExtension

# Create application
app = Flask(__name__)
app.config.from_pyfile('config.py')
db = SQLAlchemy(app)
app.debug = True
toolbar = DebugToolbarExtension(app)

@app.route('/', methods=['GET', 'POST'])
def index():
    return '<a href="/admin/">Click me to get to Home!</a>'

import views
import models