Drug-induced thrombocytopenia results from an immune reaction that causes the destruction of platelets or from the suppression of platelet production in the bone marrow, the Mayo Clinic states. Platelets help blood clot by clumping together and plugging damaged areas of the blood vessels. Thrombocytopenia can cause excessive bleeding and a rash known as petechiae, small red dots made by leaking of the small blood vessels under the skin. Many drugs can cause low platelets, which require stopping of the drug and possible steroid treatment to suppress the immune reaction.
Heparin
Heparin, a drug given to thin blood in people with a tendency to form clots, may be the most common drug cause of thrombocytopenia, according to Medline Plus. Up to 5 percent of people taking heparin develop thrombocytopenia, the Merck Manual reports. Platelets in heparin-induced thrombocytopenia may paradoxically clump and block blood vessels, leading to blood clots in arteries and veins rather than excessive bleeding, Merck explains.
Quinidines
Quinine and other quinidines, medications given to treat abnormal heart rhythms, nocturnal leg cramps and malaria, commonly cause thrombocytopenia. Lead author Allen Brinker of the Food and Drug Administration reports in a July 26, 2002 article published in the "American Journal of Hematology" entitled "Spontaneous reports of thrombocytopenia in association with quinine" that clinical attributes and timing related to regulatory action that sudden, severe thrombocytopenia may result after taking quinine and dietary supplements and foods containing quinine.
Gold Salts
Gold salts, used to treat rheumatoid arthritis, are more likely to cause thrombocytopenia in patients who have the antigen HLA-DR3 in their blood, editor of "Journal of Rheumatology" and author, Duncan Gordon, M.D., reports in an "UpToDate" article entitled "Major side effects of gold".
Other Medications
Many other drugs have been implicated in causing DITP, including non-steroidal anti-inflammatory medications, acetaminophen, or Tylenol, oral diabetic medications, ranitidne (Zantac) and diuretics. Drugs that suppress manufacture of platelets rather than destroying them include chemotherapy medications and valproic acid, a medications used to treat seizures, according to Medline Plus.
Several antibiotic classes can also cause drug induced thrombocytopenia (DITP). Sulfonamides such as Bactrim, Vancomycin and penicillin are among the common antibiotic causes of DITP.
References
- Mayo Clinic: Thrombocytopenia
- Merck Manual: Thrombocytopenia
- Medline Plus: Thrombocytopenia: Drug Induced
- American Journal of Hematology: Spontaneous reports of thrombocytopenia in association with quinine: Clinical attributes and timing related to regulatory action; A. Brinker
- UpToDate: Major Side Effects of Gold; Daniel Gordon, M.D.
