Cinchona pubescens hence its nickname the red quinine tree. Its flowers form in large panicles. They are pink and fragrant, while in the Galapagos they are light pink. "C. pubescens" has the widest distribution of all "Cinchona" species, with the native range spanning Costa Rica, Panama, Venezuela, Colombia, Ecuador, Peru, and Bolivia. In Ecuador it is distributed within an altitude from . It also grows well in volcanic soil with high nutrient levels. C. pubescens is a resilient species that is able to recover from even extreme damage. If the tree is felled but the stump is left, it can grow back
Analgesic tolerance, which may be of particular concern regarding patients suffering with chronic pain and requiring an analgesic over long periods. Opioid tolerance is often addressed with opioid rotation therapy in which a patient is routinely switched between two or more non-cross-tolerant opioid medications in order to prevent exceeding safe dosages in the attempt to achieve an adequate analgesic effect. Opioid tolerance should not be confused with opioid-induced hyperalgesia. The symptoms of these two conditions can appear very similar but the mechanism of action is different. Opioid-induced hyperalgesia is when exposure to opioids increases the sensation of pain (hyperalgesia) and can