From the Guidelines
Certain medications used to treat meningitis, such as trimethoprim-sulfamethoxazole (TMP-SMX) and vancomycin, have been associated with thrombocytopenia, a condition characterized by low platelet count [ 1 ].
Key Medications
- Trimethoprim-sulfamethoxazole (TMP-SMX): High-dose TMP-SMX administered for extended durations may increase the risk of thrombocytopenia [ 1 ].
- Vancomycin: has also been linked to thrombocytopenia, particularly when used at high doses for prolonged periods [ 1 ].
- Pipericillin/tazobactam: is another medication that has been implicated in causing thrombocytopenia [ 1 ].
Important Considerations
- The risk of thrombocytopenia associated with these medications may be increased with high doses and prolonged durations of use.
- Laboratory testing, such as demonstrating the presence of drug-dependent platelet antibodies, is necessary to confirm the diagnosis of drug-induced immune thrombocytopenia [ 1 ].
From the FDA Drug Label
Thrombocytopenia Sulfamethoxazole and trimethoprim-induced thrombocytopenia may be an immune-mediated disorder. Severe cases of thrombocytopenia that are fatal or life threatening have been reported In elderly patients concurrently receiving certain diuretics, primarily thiazides, an increased incidence of thrombocytopenia with purpura has been reported
- Sulfamethoxazole and trimethoprim can cause thrombocytopenia (low platelet count) as an immune-mediated disorder, with severe cases being fatal or life-threatening 2.
- The risk of thrombocytopenia may be increased when sulfamethoxazole and trimethoprim is co-administered with certain diuretics, primarily thiazides, in elderly patients 2 2.
From the Research
Meningitis Medications and Thrombocytopenia
- Trimethoprim/sulfamethoxazole (TMP/SMX) is a commonly used antibiotic for the treatment and prophylaxis of various infections, including meningitis.
- TMP/SMX has been associated with thrombocytopenia, a condition characterized by a low platelet count, in several studies 3, 4.
- The incidence of thrombocytopenia due to TMP/SMX can be as high as 12.5% in some patient populations 4.
- Thrombocytopenia associated with TMP/SMX can be severe and potentially life-threatening, with platelet counts ≤10×10^9/L 3.
- The exact mechanism of TMP/SMX-induced thrombocytopenia is not fully understood, but it is thought to be dose- and duration-independent 3.
Other Side Effects of TMP/SMX
- In addition to thrombocytopenia, TMP/SMX has been associated with other side effects, including aseptic meningitis, hepatitis, and cholestasis 5, 6, 7.
- Aseptic meningitis is a rare but potentially life-threatening side effect of TMP/SMX, and clinicians should be aware of this possibility in patients presenting with meningeal signs and symptoms 5, 6, 7.
- The diagnosis of TMP/SMX-induced aseptic meningitis can be challenging, and a thorough evaluation for infectious causes is necessary to rule out other etiologies 6, 7.