This e-newsletter is a monthly publication of the Platelet Disorder Support Association. The information in this newsletter is for educational purposes only. For advice on your unique medical condition, please consult a health care professional.
ITP and Platelet Disorders Research and Treatments
- Common Drugs can Cause Low Platelets: A New List
- Antidepressants Associated with Brain Hemorrhage
- B-cells Go and Come in ITP
- Anti-Platelet Antibody Types May Determine Therapy Success
Hospitals, Insurance, and Medical Care
General Health and Medicine
ITP and Platelet Disorders
Research and Treatments
Some people have low platelets because of their sensitivity to over-the-counter or prescribed drugs, called drug-induced thrombocytopenia. Researchers evaluated blood tests for drug-induced thrombocytopenia and compiled a list of drugs that are likely to cause low platelets. They are: quinine (treats malaria, also found in tonic water), quinidine (for abnormal heart rhythms), trimethoprim/sulfamethoxazole (antibiotic), vancomycin (kills bacteria in intestines), penicillin (antibiotic), rifampin (antibiotic), carbamazepine (controls seizures), ceftriaxone (antibiotic), ibuprofen (relieves pain and swelling, ex: Advil, Motrin), mirtazapine (anti-depressant), oxaliplatin and suramin (chemotherapies); the glycoprotein IIbIIIa inhibitors abciximab, tirofiban and eptifibatide; and heparin (anti-clotting agents).
For more information on drug-induced thrombocytopenia see PDSA's 'Warnings' page:
Arnold DM et al. "A systematic evaluation of laboratory testing for drug-induced immune thrombocytopenia." J Thromb Haemost. 2012 Nov 3.
Selective serotonin reuptake inhibitors (SSRIs), common types of antidepressants marketed under nearly 50 brand names (ex: Prozac,and Zoloft), can increase the risk of bleeding in the brain, according to new research that examined prior studies on the subject. While the increased risk is small, about 1 in 10,000 people per year, the findings are consistent and logical. SSRIs can reduce the ability of platelets to clot, can decrease the platelet count, and have been associated with bleeding in the stomach. An editorial about the research concludes: "these findings emphasize the importance of appropriate patient selection and avoidance of inappropriate prescribing, which assumes particular importance in patients at increased risk of (brain hemorrhage).
Norton A. "Antidepressants linked to risk of brain bleeds." Reuters. Oct. 17, 2012.
McGrath ER, O'Donnell MJ. "Estimating treatment effects in observational studies." Neurology. 2012;79:1844–1845.
Hackam DG, Mrkobrada M. "Selective serotonin reuptake inhibitors and brain hemorrhage: A meta-analysis." Neurology. 2012 Oct 30;79(18):1862-5.
Researchers knew that people with ITP had deficient T-regulatory cells (Tregs, a type of white blood cell) and that these cells increased upon remission. New research shows that people with ITP also have deficient B-regulatory cells (Bregs, another type of white blood cell) and these cells also increase with remission. Both Tregs and Bregs are involved in regulating autoimmunity by helping to determine whether something is a normal part of the body or a foreign invader. In addition to a lower number of Bregs in ITP, the Bregs that are present don't function normally. When ITP research subjects were given a thrombopoietin agent, both their Breg numbers and their functionality increased. This research raises many questions. Among them: Do all ITP therapies enhance Bregs? Is the increase in Tregs and Bregs a natural function of having more platelets?
Semple J. "Bregging rights in ITP." Blood, October 18, 2012 vol. 120 no. 16 3169.
People with ITP can have antibodies attached in two different places on platelets: glycoprotein (GP)IIbIIIa or GPIb. The location of anti-platelet antibodies affects how the body eliminates platelets and can make a difference in which treatments work best. In the past researchers found that IVig didn't work well in people with the GPIb antibody placement. Now they have determined that people with GPIb antibodies don't respond as well to steroids.
Li J et al. "Fc-independent phagocytosis: Implications for IVIG and other therapies in immune-mediated thrombocytopenia." Cardiovasc Hematol Disord Drug Targets. 2012 Oct 18.
and Medical Care
About 180,000 people die each year and another 1.4 million are seriously hurt from hospital-induced infections and mistakes. That's the bad news. The good news is that you can help prevent hospital errors. Consumer Reports published suggestions for preventing problems during a hospital stay (free) and ranked hospitals on various safety criteria (subscription required). See the Consumer Reports' guide at:
Hospitals can obviously do more to prevent medical errors. Some recommendations are a simple as making patient safety a priority and sharing more information with patients and the public. You can access free hospital safety ratings at: http://www.hospitalsafetyscore.org and hospital ratings using Medicare data at: http://www.hospitalcompare.hhs.gov
Makary M. "How to Stop Hospitals From Killing Us: Medical errors kill enough people to fill four jumbo jets a week. A surgeon with five simple ways to make health care safer." Wall Street Journal. Sept. 21, 1012:
It is not easy to balance the pros and cons of various treatments for ITP. However, to make a good treatment plan for any disease, doctors need to fully understand patient preferences and the trade-offs patients would make. Many doctors think they are taking people's desires into account, but when closely examined, that is often not the case. To make sure the treatments are in line with patient values, researchers have some suggestions for doctors: fully understand the patient's preferences, adopt a mindset of scientific detachment, and include the patient as part of the decision team.
Huston M et al. "New Style and New Content for ClinicalTrials.gov." NLM Tech Bull. 2012 Jul-Aug;(387):e5 (editor note added September 20, 2012Mulley AG et al. "Stop the silent misdiagnosis: patients' preferences matter." BMJ 2012;345:e6572.
General Health and Medicine
Fruit juice, not just grapefruit juice, can prevent prescription drugs from working as intended. Fruit juice can inhibit organic anion–transporting polypeptides (OATP), proteins involved in breaking down drugs and getting them into the blood stream. Researchers tested orange and apple juice and found that even drinks containing small amounts of fruit juice hindered drug action. Because apple and orange juice are consumed in much larger quantities than grapefruit juice, this research shows that the juice/drug interaction could have a greater impact on medical practice.
Important Note: The OATP/fruit juice connection is especially important for people with ITP taking eltrombopag (Promacta®) since OATP is involved in metabolizing that drug.
Dolton MJ et al. "Fruit juices as perpetrators of drug interactions: the role of organic anion-transporting polypeptides." Clin Pharmacol Ther. 2012 Nov;92(5):622-30.
Takeuchi K et al. "Pharmacokinetics and hepatic uptake of eltrombopag, a novel platelet-increasing agent." Drug Metab Dispos. 2011 Jun;39(6):1088-96.
The Environmental Working Group has published its 2012 Shopper's Guide to Pesticides in Produce. This useful guide, available in a grocery-story-ready print version, lists vegetables that are most frequently contaminated with pesticides and those with the least contamination. This is helpful for people who want to reduce both their pesticide exposure and their food budget. View the guide at:
Important Note: Pesticides have been linked to increased platelet destruction. For more information about this and other environmental influences on platelet count see the 'Warnings' page.
This e-newsletter is published by the Platelet Disorder Support Association, 133 Rollins Avenue, Suite 5, Rockville, MD 20852, phone 1-87-Platelet, fax: 301-770-6638, web: http://www.pdsa.org, e-mail: firstname.lastname@example.org