DRUG-DRUG INTERACTIONS

I think the following will be useful to learn:

• Cisplatin can lead to renal damage which can therefore reduce the renal clearance of methotrexate
• If cisplatin is given before topotecan, exposue to topotecan increases, due to reduced renal clearance of topotecan

• Allopurinol reduces the metabolic inactivation of 6-mercaptopurine and increases its toxicity.
• Penicillins, Probenacid and sulfonamides and NSAIDs reduce the renal clearance of Methotrexate. Compete for the tubular secretion pathway

• If Carboplatin/Cisplatin are administered simultaneously with paclitaxel there is less myelosuppression compared to when platinum preceeds paclitaxel.
• There is increased neurotoxicity when cisplatin ans paclitaxel are administered together. This interaction is worse when paclitaxel infusion has along duration.

• Methotrexate can be displaced from Albumin by 1.sulphonamides 2.tetracycline 3.chloramphenicol 4.phenytoin 5.NSAIDs. This will increase the plasma concentration, causing more side effects such as mucositis and myelosuppression

RANDOM PHARM FACTS

• MESNA binds acrolein (metabolite of ifosamide) that is irritant to urothelium
• Dexrasone iv is used with anthracycline extravasation
• Epirubicin and Doxorubicin are a red solution and can cause urine and sweat to appear pink after treatment.
• Methotrexate is yellow
• Mitomycin C is a light blue solution
• You can give vincristine, bleomycin and gemcitabine on day 8 as they have less myeloosuprresive effects on the pre-cursor cells.
• Gemcitabine and Fludarabine have synergy with cisplatin by inhibiting the repair of cisplatin adducts (by NER)
• 5-FU as a BOLUS affects RNA metabolism
• 5-FU as an INFUSION affects DNA metabolism