Nifedipine Doxorubicin

CALCIUM CHANNEL BLOCKERS DOXORUBICIN t serum concentrations and efficacy of doxorubicin when co-administered with verapamil, nicardipine and possibly diltiazem and nifedipine however, no cases of doxorubicin toxicity have been reported Uncertain however, verapamil is known to inhibit intestinal P-gp, which may t the bioavailability of doxorubicin Watch for symptoms/signs of toxicity (tachycardia, heart failure and hand-foot syndrome)... 

A review of the literature shows that photochemical reactions generally follow first-order kinetics. However, pseudo first-order, zero-order, and even fractional-order kinetics have been reported. Drugs reported to follow first-order kinetics include nifedipine (8) doxepin (41), riboflavin (28), minoxidil (48), adriamycin (52), doxorubicin, daunorubicin and epirubicin (61), folic acid (66), menadione sodium bisulfite (67), tetracycline hydrochloride (71), decarbazine (73), furosemide (74), democlocycline (76) and hydrocortisone, and prednisolone (90). Apparent pseudo first-order rate has been reported for pyridoxine (84). Indomethacin (91), sodium nalidixate (65), methotrexate (92), and metronidazole (68) have been reported... 

The efficacy of doxorubicin can be increased by verapamil and nicardipine in doxorubicin-resistant tissue culture systems, while nifedipine has only minimal activity. A study in five patients with small cell lung cancer given doxorubicin, vincristine, etoposide and cyclophosphamide showed that when they were given verapamil 240 to 480 mg daily the AUC of doxorubicin was doubled, its peak serum levels were raised and its clearance was reduced. No increased toxicity was seen in this study. However, although another study found no increase in non-cardiac toxic-ities, verapamil caused an unacceptable degree of cardiac toxicity. Be alert for this possibility if both drugs are used. 

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