Thiotepa
Thiotepa is a highly potent, cell-cycle non-specific **alkylating antineoplastic agent**. In veterinary medicine, it is primarily utilized for: * **Intracavitary instillation** to manage malignant neoplastic effusions (e.g., pleural or peritoneal). * **Intravesical instillation** for transitional cell carcinomas of the bladder (though studies indicate it is significantly less effective than systemic doxorubicin/cyclophosphamide protocols). * Systemic adjunctive therapy for various carcinomas. > **Clinical Pearl:** Thiotepa has a very narrow therapeutic index. Because it is a hazardous cytotoxic drug, strict handling precautions (e.g., use of biologic safety cabinets, closed-system transfer devices, and appropriate PPE) are mandatory to protect veterinary personnel from mutagenic and teratogenic risks.
Mecanismo: Thiotepa acts as a polyfunctional alkylating agent. * **Mechanism:** It undergoes conversion to its active metabolite, **TEPA**, which directly cross-links DNA strands by binding to guanine bases. * **Pathway:** DNA cross-linking → interference with DNA replication and RNA transcription → cell cycle arrest and apoptosis. * **Specificity:** It is **cell-cycle non-specific**, meaning it exerts cytotoxic effects on both resting and actively dividing cells. * When administered via the intracavitary route, it is believed to control malignant effusions through a direct, localized antineoplastic effect on the serosal surfaces.
Dosificación por especie
- Intracavitary use for neoplastic effusions or systemically for adjunctive therapy of carcinomas · 0.2-0.5 mg/m 2 · intracavitary; IV · Not specified · Not specified · Consultation with a veterinary oncologist and referral to current veterinary oncology references are strongly recommended.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Hypersensitivity to thiotepa
- Pregnancy (teratogenic and mutagenic - FDA Category D)
Efectos adversos
- Leukopenia (most common)
- Thrombocytopenia
- Anemia
- Pancytopenia
- Vomiting
- Diarrhea
- Stomatitis
- Intestinal ulceration
- Dizziness (reported in humans)
- Headache (reported in humans)
Interacciones farmacológicas
- Immunosuppressive drugs (e.g., azathioprine, cyclophosphamide, corticosteroids) · May increase the risk of severe infections due to additive immunosuppression.
- Myelosuppressive drugs (e.g., chloramphenicol, flucytosine, amphotericin B, colchicine) · Extreme caution required; bone marrow depression may be additive and lead to severe pancytopenia.
- Live Vaccines · Increased risk of vaccine-induced infection or reduced vaccine efficacy; use with extreme caution, if at all.
Monitorización
- Clinical efficacy (tumor response or reduction in effusion)
- CBC with platelets (monitor closely for myelosuppression)
- Serum uric acid levels
Sobredosis
There is **no specific antidote** for a thiotepa overdose. Treatment is primarily supportive and symptomatic. If severe hematologic toxicity (profound myelosuppression) occurs, aggressive supportive therapy is required, which may include **transfusions of appropriate blood products**, broad-spectrum prophylactic antibiotics, and isolation to prevent secondary infections.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.