From the FDA Drug Label
Hemic and Lymphatic Systems: Anemia, including hemolytic anemia, thrombocytopenia, thrombocytopenic purpura, eosinophilia, leukopenia, and agranulocytosis have been reported. These reactions are usually reversible on discontinuation of therapy and are believed to be hypersensitivity phenomena
The incidence of thrombocytopenia associated with Amoxicillin (Amoxicillin) Clavulanic Acid (Clavulanate) is not explicitly stated in the drug label, but it is listed as one of the reported adverse reactions in the Hemic and Lymphatic Systems category 1.
From the Research
Thrombocytopenia is a rare side effect of amoxicillin-clavulanic acid, occurring in less than 1% of patients taking this antibiotic, as reported in a case study from 2014 2. The exact incidence is difficult to determine precisely due to limited reporting and the challenge of establishing causality. When it does occur, thrombocytopenia typically develops within 7-14 days after starting the medication, though it can appear earlier in patients previously exposed to the drug. The mechanism is usually immune-mediated, where the drug or its metabolites trigger antibody formation that targets platelets for destruction. Risk factors include previous drug allergies, older age, and longer duration of treatment. Some studies suggest that the incidence of drug-induced thrombocytopenia is estimated to occur at a minimum of 10 cases per million per year 3. However, a more recent study from 2020 highlights the importance of recognizing antibiotic-induced thrombocytopenia in the postoperative patient, especially with the increasing use of antibiotics in perioperative prophylaxis protocols 4. Patients taking amoxicillin-clavulanic acid should be aware of symptoms such as unusual bruising, petechiae (small red or purple spots on the skin), or bleeding from gums or nose, which warrant immediate medical attention. If thrombocytopenia is suspected, the medication should be discontinued immediately, and platelet counts typically recover within 7-10 days after stopping the drug. Healthcare providers should consider alternative antibiotics for patients with a history of drug-induced thrombocytopenia. It is also important to note that amoxicillin-clavulanic acid can interact with other medications, such as warfarin, and increase the risk of bleeding 5. In rare cases, amoxicillin-clavulanic acid can also cause extreme thrombocytosis, as reported in a case study from 2006 6. However, the most recent and highest quality study on this topic is from 2020, which highlights the importance of recognizing antibiotic-induced thrombocytopenia in the postoperative patient 4. Key points to consider include:
- Thrombocytopenia is a rare side effect of amoxicillin-clavulanic acid
- The exact incidence is difficult to determine precisely
- Risk factors include previous drug allergies, older age, and longer duration of treatment
- Patients should be aware of symptoms such as unusual bruising or bleeding
- If thrombocytopenia is suspected, the medication should be discontinued immediately
- Healthcare providers should consider alternative antibiotics for patients with a history of drug-induced thrombocytopenia.