Ethylenimines

Ethylenimines

Thiotepa, an ethylenimine derivative, is a multifunctional alkylat-ing drug.

Pharmacokinetics

After I.V. administration, thiotepa is 100% bioavailable. Significant systemic absorption may occur when thiotepa is administered into pleural (around the lungs) or peritoneal (abdominal) spaces to treat malignant effusions or is instilled into the bladder.

Metabolism and excretion

Thiotepa crosses the blood-brain barrier and is metabolized exten-sively in the liver. Thiotepa and its metabolites are excreted in urine.

Pharmacodynamics

Thiotepa exerts its cytotoxic activity by interfering with DNA replication and RNA transcription. Ultimately, it disrupts nucleic acid function and causes cell death.

Pharmacotherapeutics

Thiotepa is used to treat bladder cancer. This alkylating drug is also prescribed for palliative (symptom-relief) treatment of lym-phomas and ovarian or breast cancers.

Wait! There’s more

Thiotepa is used for the treatment of intracavitary effusions (accu-mulation of fluid in a body cavity). It may also prove useful in the treatment of lung cancer.

Drug interactions

Thiotepa may interact with other drugs.

·                 Concurrent use of thiotepa, anticoagulants, and aspirin may in-crease the risk of bleeding.

·                 Taking thiotepa with neuromuscular blocking drugs may pro-long muscular paralysis.

·                 Concurrent use of thiotepa and other alkylating drugs or radia-tion therapy may intensify toxicity rather than enhance the thera-peutic response.

It’ll take your breath away

When used with succinylcholine, thiotepa may cause prolonged respirations and apnea (periods of not breathing). Thiotepa ap-pears to inhibit the activity of cholinesterase, the enzyme that de-activates succinylcholine. (See Adverse reactions to thiotepa.)