Itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itch leads to a scratch reflex. Hydroxychloroquine coat Difficulty sleeping side effect of plaquenil Will plaquenil help irritable bowel syndrome Hydroxychloroquine 200 mg tablet Drugs that release histamine can cause itching. Example Opioids, Chloroquine. Cholinergic Urticaria. It is a skin rash appearing on thighs shortly after running, walking or taking hot shower that lasts upto an hour or two. One should avoid scratching, stop running in hot weather and use lukewarm shower. The itching reactions caused by chloroquine or cowhage don't respond to anti-histamines. Certain opioids used to treat pain, such as morphine, can also cause a histamine-independent itch as a side. Several studies have suggested that there could be heredo-familial factors influencing chloroquine induced pruritus2,9,10. Study has shown that, 133 40.20% of 331 patients experienced itching to chloroquine and all those prone to itching to chloroquine did so after oral administration of the drug. Pain and itch have very different behavioral response patterns. Unmyelinated nerve fibers for itch and pain both originate in the skin; however, information for them is conveyed centrally in two distinct systems that both use the same nerve bundle and spinothalamic tract. How chloroquine causes itch Mechanisms of Chloroquine-Induced Body-Scratching Behavior in., How a new understanding of itch leads to better pain. Plaquenil and lupus rash Itchy skin is a common problem that can be hard to diagnose. WebMD looks at the possible causes, from minor irritants to serious illnesses. Itchy Skin & Itching 22 Possible Causes You Feel Itchy All Over. Chloroquine-induced Pruritus. Itch - Wikipedia. Chloroquine phosphate may cause an upset stomach. Take chloroquine phosphate with food. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use chloroquine phosphate exactly as directed. Do not use more or less of it or use it more often than prescribed by your. Effects of chloroquine? Chloroquine is a relatively well-tolerated. medicine. The most common adverse reactions reported are stomach pain, nausea, vomiting, and headache. These side effects can often be lessened by taking chloroquine with food. Chloroquine may also cause itching in some people. All medicines may have some side effects. A severe eye problem has happened with chloroquine. This may lead to lasting eyesight problems. The risk may be higher if you have some types of eye or kidney problems. The risk may also be higher with some doses of chloroquine, if you use chloroquine for longer than 5 years, or if you take certain other drugs like tamoxifen.