Interactions between anticancer drugs and other clinically used pharmaceuticals. A review

Anesthesia Medications and Interaction with Chemotherapeutic Agents

Cancer is now a leading health concern worldwide. In an effort to provide these patients with adequate care, coordination between anesthesiologists and surgeons is crucial. In cancer-related treatment, it is very clear that radio-chemotherapy and medical procedures are important. There are some obstacles to anesthesia when dealing with cancer treatment, such as physiological disturbances, tumor-related symptoms, and toxicity in traditional chemotherapy treatment. Therefore, it is important that a multisystemic, multidisciplinary and patient-centered approach is used to preserve perioperative homeostasis and immune function integrity. Adding adjuvants can help increase patient safety and satisfaction and improve clinical efficacy. Correctly paired anesthetic procedures and medications will reduce perioperative inflammatory and immune changes that could potentially contribute to improved results for future cancer patients. Further research into best practice strategies is required which will help to enhance the acute and long-term effects of cancer care in clinical practice.

Design of polymeric core-shell carriers for combination therapies

Particle engineering for co-delivery of drugs has the potential to combine multiple drugs with different pharmaceutical mechanisms within the same carrier, increasing the therapeutic efficiency while improving patient compliance. This work proposes a novel approach for producing polymer-polymer core-shell microparticles by multi-step processing of emulsion and spray drying. The particle core was obtained by an oil-in-water emulsion of poly(ε-caprolactone) (PCL) loaded with curcumin (CM), followed by the resuspension in poly(vinyl alcohol) (PVA) containing ciprofloxacin (CPx) forming the shell layer by spray-drying. The obtained core-shell particles showed an average size of 3.8 ± 1.2 μm, which is a suitable size for inhalation therapies. The spatial distribution of the drugs was studied using synchrotron-based macro attenuated total reflection Fourier transform infrared (macro ATR-FTIR) microspectroscopy to map the chemical distribution of the components within the particles and supported the presence of CM and CPx in the core and shell layers, respectively. The formation of the core-shell structure was further supported by the differences in the release profile of CM from these particles, when compared to the release profile observed for the single particle structure (PCL-CM). Both empty and drug-loaded carriers (up to 100 μg.mL^-1) showed no cytotoxic effects on A549 cells while exhibiting the antibacterial activity of CPx against Gram-positive and Gram-negative bacteria. These polymer core-shell microparticles provide a promising route for the combination and sequential drug release therapies, with the potential to be used in inhalation therapies.

Revolutionizing technologies of nanomicelles for combinatorial anticancer drug delivery

Insufficient efficacy of current single drug therapy of cancers have led to the advancement of combination drug-loaded formulations. Specifically, polymeric micelles have been focused on as efficient injectable vehicles for the delivery of several anticancer drugs simultaneously to cancer cells. These nano delivery systems have evolved with advancements in the area of nanotechnology. The current review presents a summary of the past events that have led to the procession of nanomicelles and novel nanotechnologies for combinatorial drug delivery. It also focuses on the advantages, disadvantages, and considerations for the design of nanotechnologies for combinatorial drug delivery systems. The opportunities and challenges of nanotechnologies in drug delivery to overcome current disadvantages are also discussed. Furthermore, we have added findings regarding the trends and perspectives regarding nanotechnologies for combinatorial anticancer drug delivery.

A small oxazine compound as an anti-tumor agent: a novel pyranoside mimetic that binds to VEGF, HB-EGF, and TNF-α

A novel pyranoside mimetic compound, DMBO (2-(2,6-difluorophenyl)-5-(4-methoxyphenyl)-1-oxa-3-azaspiro[5.5]undecane), was designed and synthesized. The sugar mimicking behavior of DMBO was addressed by its ability to bind several growth factors/cytokines such as vascular endothelial growth factor (VEGF), heparin-binding epidermal growth factor-like growth factor (HB-EGF), and tumor necrosis factor (TNF)-α as demonstrated by the recently developed surface plasmon resonance assay. DMBO exhibited strong anti-proliferation activity in vitro against tumor cells including a highly metastatic murine osteosarcoma cell line LM8G7 that secretes VEGF as well as two human ovarian cell lines, OVSAHO and SKOV-3, which secrete TNF-α and HB-EGF respectively. Furthermore, DMBO inhibited the metastatic activity to the mouse liver of LM8G7 cells injected from a lateral tail vein, and affected the heparan-degrading activity of LM8G7 cells. Here, we report that DMBO acts as a human heparanase inhibitor in vitro possibly as a substrate mimetic. DMBO also inhibited the migration and invasion of LM8G7 cells and angiogenic events such as endothelial cell proliferation, migration and capillary tube-like formation in vitro. More prominently, the administration of DMBO with heparin resulted in synergistic anti-tumor effects in mouse modelofosteosarcoma. These preclinical data shows the potential anti-cancer effects of DMBO.

Drug–drug interactions in oncology: Why are they important and can they be minimized?

Adverse drug-drug interactions are a major cause of morbidity and mortality. Cancer patients are at particularly high risk of such interactions because they commonly receive multiple medications, including cytotoxic chemotherapy, hormonal agents and supportive care drugs. In addition, the majority of cancer patients are elderly, and so require medications for co-morbid conditions such as cardiovascular, gastrointestinal, and rheumatological diseases. Furthermore, the age-related decline in hepatic and renal function reduces their ability to metabolize and clear drugs and so increases the potential for toxicity. Not all drug-drug interactions can be predicted, and those that are predictable are not always avoidable. However, increased awareness of the potential for these interactions will allow healthcare providers to minimize the risk by choosing appropriate drugs and also by monitoring for signs of interaction. This review considers the basic principles of drug-drug interactions, and presents specific examples that are relevant to oncology.

The importance of drug interactions in epilepsy therapy

Long-term antiepileptic drug (AED) therapy is the reality for the majority of patients diagnosed with epilepsy. One AED will usually be sufficient to control seizures effectively, but a significant proportion of patients will need to receive a multiple AED regimen. Furthermore, polytherapy may be necessary for the treatment of concomitant disease. The fact that over-the-counter drugs and nutritional supplements are increasingly being self-administered by patients also must be considered. Therefore the probability of patients with epilepsy experiencing drug interactions is high, particularly with the traditional AEDs, which are highly prone to drug interactions. Physicians prescribing AEDs to patients with epilepsy must, therefore, be aware of the potential for drug interactions and the effects (pharmacokinetic and pharmacodynamic) that can occur both during combination therapy and on drug discontinuation. Although pharmacokinetic interactions are numerous and well described, pharmacodynamic interactions are few and usually concluded by default. Perhaps the most clinically significant pharmacodynamic interaction is that of lamotrigine (LTG) and valproic acid (VPA); these drugs exhibit synergistic efficacy when coadministered in patients with refractory partial and generalised seizures. Hepatic metabolism is often the target for pharmacokinetic drug interactions, and enzyme-inducing drugs such as phenytoin (PHT), phenobarbitone (PB), and carbamazepine (CBZ) will readily enhance the metabolism of other AEDs [e.g., LTG, topiramate (TPM), and tiagabine (TGB)]. The enzyme-inducing AEDs also enhance the metabolism of many other drugs (e.g., oral contraceptives, antidepressants, and warfarin) so that therapeutic efficacy of coadministered drugs is lost unless the dosage is increased. VPA inhibits the metabolism of PB and LTG, resulting in an elevation in the plasma concentrations of the inhibited drugs and consequently an increased risk of toxicity. The inhibition of the metabolism of CBZ by VPA results in an elevation of the metabolite CBZ-epoxide, which also increases the risk of toxicity. Other examples include the inhibition of PHT and CBZ metabolism by cimetidine and CBZ metabolism by erythromycin. In recent years, a more rational approach has been taken with regard to metabolic drug interactions because of our enhanced understanding of the cytochrome P450 system that is responsible for the metabolism of many drugs, including AEDs. The review briefly discusses the mechanisms of drug interactions and then proceeds to highlight some of the more clinically relevant drug interactions between AEDs and between AEDs and non-AEDs. Understanding the fundamental principles that contribute to a drug interaction may help the physician to better anticipate a drug interaction and allow a graded and planned therapeutic response and, therefore, help to enhance the management of patients with epilepsy who may require treatment with polytherapy regimens.

The role of human cytochrome P450 enzymes in the metabolism of anticancer agents: implications for drug interactions

1. Little information is available about the pharmacokinetic interactions of anticancer drugs in man. However, clinically significant drug interactions do occur in cancer chemotherapy, and it is likely that important interactions have not been recognized. 2. Specific cytochrome P450 (CYP) enzymes have been recently shown to be involved in the metabolism of several essential anticancer agents. In particular, enzymes of the CYP3A subfamily play a role in the metabolism of many anticancer drugs, including epipodophyllotoxins, ifosphamide, tamoxifen, taxol and vinca alkaloids. CYP3A4 has been shown to catalyse the activation of the prodrug ifosphamide, raising the possibility that ifosphamide could be activated in tumour tissues containing this enzyme. 3. As examples of recently found, clinically significant interactions, cyclosporin considerably increases plasma doxorubicin and etoposide concentrations. Although cyclosporin and calcium channel blockers may influence the pharmacokinetics of certain anticancer agents by inhibiting their CYP3A mediated metabolism, it is more likely that these P-glycoprotein inhibitors inhibit P-glycoprotein mediated drug elimination. 4. Appropriate caution should be exercised when combining P-glycoprotein inhibitors and potential CYP3A inhibitors with cancer chemotherapy.

Interaction of the antiemetics ondansetron and granisetron with the cytotoxicity induced by irradiation, epirubicin, bleomycin, estramustine, and cisplatin in vitro

At cancer treatment, the use of antiemetics are often needed due to induction of nausea and vomiting. Some antiemetics have been shown to interact with the direct cytotoxic effects. The newly developed antiemetics have, as far as we know, not been studied in this respect. In the present study, the effects of the 5-HT3 receptor antagonists ondansetron and granisetron were evaluated on the cytotoxicity, induced by irradiation, bleomycin, epirubicin, estramustine, and cisplatin using fibroblasts (V79) and lung cancer cells (P31) in vitro. Ondansetron or granisetron (10(-5) mol/l) had no effect on the survival of irradiated cells. Granisetron (10(-5) mol/l) significantly potentiated cytotoxicity of 2.5 mg/l epirubicin on fibroblasts whereas the effect of granisetron (10(-7) mol/l) on the cytotoxic effect of 25 mg/l bleomycin, and estramustine (80 mg/l) seemed additive to lung cancer cells. Ondansetron was non-interactive with the cytotoxicity induced by any of the anti-cancer drugs. Although the encountered observation with an enhancing effect of granisetron on the epirubicin-induced cytotoxicity is seen in a specific experimental situation in vitro, the fact that 5-HT3 receptor antagonists are routinely used during cancer treatment indicate that attention should be given to a possible interaction with the antineoplastic action of cancer treatment.

Effects of clonidine-induced hypotension and dopamine-induced hypertension on blood flows in prostatic adenocarcinoma (Dunning R3327) and normal tissues

In the present study it was investigated whether hypertension induced by dopamine or hypotension induced by clonidine could influence the relative blood distribution in a s.c. transplanted prostatic adenocarcinoma in relation to blood flow in normal tissues in rats. The blood flow was measured by using a radioactive microspheres technique. A bolus injection of 5 micrograms clonidine caused a decrease in the systemic blood pressure with 15-45 mm Hg, and blood flow to the central parts of the tumor, decreased with more than 50%. In the prostate, testes and ileo-psoas muscle a similar reaction was seen. During an infusion of 95-120 micrograms/kg/min dopamine, the blood pressure increased with 15-30 mm Hg, but the blood flow to the tumor was unchanged. However, in the testes and kidneys a decreased blood flow was observed. Moreover, mean blood flow to the central parts of the tumor decreased with increase in tumor size. The results further indicated that hyper- or hypotension or concomitantly given vasoactive drugs with the specific cancer treatment can have unwarranted effects on the distribution of cytotoxic drugs and oxygenation of the tumor.