Quinine the Quechua, who are indigenous to Peru, Bolivia and Ecuador, to halt shivering due to low temperatures. The Quechuas would mix the ground bark of cinchona trees with sweetened water to offset the bark's bitter taste, thus producing tonic water. The Jesuits were the first to bring cinchona to Europe. The Spanish were aware of the medicinal properties of cinchona bark by the 1570s or earlier: Nicolás Monardes (1571) and Juan Fragoso (1572) both described a tree that was subsequently identified as the cinchona tree and whose bark was used to produce a drink to treat diarrhea. Quinine has been
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