Erythromycin Amiodarone

Maintenance doses widely vary among patients (e.g., from 1 to 20 mg/day for warfarin), and are influenced by diet (variable vitamin K intake) and medications that affect coumarin metabolism (decreased drug clearance e.g., cotrimoxazole, amiodarone, erythromycin increased clearance e.g., barbiturates, carbamaze-pine, rifampin). Thus, regular monitoring is needed... 

Amiodarone, ampicillin, amoxicillin, captopril, chlorpro-mazine, ceftriaxone, erythromycin estolate, estrogen products, methimazole, nafcillin, rifampin, sulfonamide antimicrobials, and sulfonylureas... 

Specific concomitant medications or consumptions (check specific statin package insert for warnings) fibrates (especially gemfibrozil, but other fibrates too), nicotinic acid (rarely), cyclosporine, azole antifungals such as itraconazole and ketoconazole, macrolide antibiotics such as erythromycin and clarithromycin, protease inhibitors used to treat Acquired Immune Deficiency Syndrome, nefazodone (antidepressant), verapamil, amiodarone, large quantities of grapefruit juice (usually more than 1 quart per day), and alcohol abuse (independently predisposes to myopathy)... 

The enzyme is the principal participant in N-demethylation reactions where the substrate is a tertiary amine. The list of substrates includes erythromycin, ethylmor-phine, lidocaine, diltiazem, tamoxifen, toremifene, verapamil, cocaine, amiodarone, alfentanil and terfenadine. Carbon atoms in the allylic and benzylic positions, such as those present in quinidine, steroids and cyclosporin A, are also particularly prone to oxidation by CYP3A4, a range of substrates is illustrated in Figure 7.10. 

Drugs that may affect HMG-CoA reductase inhibitors include alcohol, amiodarone, antacids, azole antifungals, bile acid sequestrants, cimetidine, cyclosporine, diltiazem, erythromycin, gemfibrozil, isradipine, nefazodone, niacin, nicotinic acid, omeprazole, phenytoin, propranolol, protease inhibitors, ranitidine, rifampin, St. John s wort, and verapamil. 

Ezetimibe/Simvastatin (Vytorin) [Antilipemic/HMG CoA Reductose Inhibitor] Uses H rp cholest olemia Action X Absorption of cholesterol phytost ol w/ HMG-CoA reductase inhibitor Dose 10/10-10/80 mg/d PO w/ cyclosporine or danazol 10/10 mg/d max w/ amio-darone or verapamil 10/20 mg/d max -1- w/ sev e renal insuff Caution [X, -] w/ CYP3A4 inhibitors (Table VI-8), gemfibrozil, niacin >lg/d, danazol, amiodarone, verapamil Contra PRG/lactation livCT Dz, t LFTs Disp Tabs SE HA, GI upset, myalgia, myopathy (muscle pain, weakness, or tendOTiess w/ CK 10 x ULN, rhab-domyolysis), Hep, Infxn Interactions t Risk of myopathy W7 clarithromycin, erythromycin, itraconazole, ketoconazole EMS None OD Sxs unknown symptomatic and supportive... 

Uses Rapid conversion of AF/artmal fluto Action Class III antiarrhythmic Dose Adults >60 kg. 0.01 mg/kg (max 1 mg) IV inf over 10 min may repeat x 1 <60 kg Use 0.01 mg/kg (ECC 2005 D/C cardioversion preferred) Caution [C, -] Contra w/ class I/III antiarrhythmics (Table VI-7) QTc >440 ms Disp Inj SE Arrhythmias, HA Interactions t Refractory effects W7 amiodarone, disopyra-mide, procainamide, quinidine, sotalol t QT int val W7 antihistamines, antidepressants, erythromycin, phenothiazines, TCAs EMS Use antihistamines w/ caution, may T QT interval OD May cause increased repolarization leading to arrhythmias, bradycardia, hypotension leading to cardiac arrest symptomatic and supportive... 

Others Acetaminophen, amiodarone, carbamazepine, delavirdine, efavirenz, nevirapine, quinidine, repaglinide, sildenafil, tadalafil, trazodone, vardenafil Amiodarone, amprenavir, atazanavir, ciprofloxacin, cisapride, clarithromycin, diltiozem, erythromycin, fluconazole, fluvoxamine, grapefruit juice (in high ingestion), indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, norfloxacin, ritonavir, telithromycin, troleandomycin, verapamil, voriconazole Carbamazepine, efavirenz, glucocorticoids, macrolide antibiotics, nevirapine, phenytoin, phenobarbital, rifabutin, rifapentine, rifampin, St. John s wort... 

CYP3A4 Amiodarone, terfenadine Carbamazepine, phenytoin Erythromycin, grapefruit juice,... 

Antibacterials Ciprofloxacin Erythromycin Isoniazid Antidepressants Flnoxetine Huvoxamine Paroxetine Antifungal drugs Fluconazole Itraconazole Ketoconazole Miconazole Antiviral drugs Indinavir Ritonavir Saquinavir Cardiovascular drugs Amiodarone Diltiazem Quinidine Verapamil... 

CYP3A4 HIV antivirals (e.g.. Ritonavir), amiodarone, cimetidine, diltiazem, erythromycin", grapefruit juice, ketoconazole... 

Ketanserin should not be combined with drugs that prolong the QT interval, e.g. class la anti-arrhythmics, amiodarone, sotalol, erythromycin. The risk of torsade de pointes secondary to hypokalaemia is increased when ketanserin is combined with thiazides or loop diuretics without concomitant use of a potassium-sparing diuretic or an angiotensin-converting enzyme (ACE) inhibitor, a 1 Antagonists... 

Drugs that may inhibit cytochrome P450 metabolism of other drugs include amiodarone, androgens, atazanavir, chloramphenicol, cimetidine, ciprofloxacin, clarithromycin, cyclosporine, delavirdine, diltiazem, diphenhydramine, disulfiram, enoxacin, erythromycin, fluconazole, fluoxetine, fluvoxamine, furanocoumarins (substances in grapefruit juice), indinavir, isoniazid, itraconazole, ketoconazole, metronidazole, mexile-tine, miconazole, nefazodone, omeprazole, paroxetine, propoxyphene, quinidine, ritonavir, sulfamethizole, verapamil, voriconazole, zafirlukast, and zileuton. 

Galantamine (Razadyne) [Cholinesterase Inhibitor] Uses Alzheimer Dz Action Acetylcholinesterase inhibitor Dose 4 mg PO bid, T to 8 mg bid after 4 wk may T to 12 mg bid in 4 wk Caution [B, ] T Effect w/ suc-cinylcholine, amiodarone, dildazem, verapamil, NSAIDs, digoxin X- effect w/ anticholinergics, T risk of death vs placebo Contra Severe renal/hepadc impair Disp Tabs, soln SE GI disturbances, wt loss, sleep disturbances, dizziness, HA Interactions T Effects W/ amitriptyline, cimeddine, erythromycin, fluoxetine, fluvoxamine, ketoconazole, paroxetine, quinidine EMS Use succinylcholine w/ caudon, may need a reduced dose monitor ECG for induced conduction abnormalities OD May cause cholinergic Sxs (SLUDGE), muscle weakness, resp depression, and Szs atropine may be used as antidote... 

Lopinavir/Ritonavir (Kaletra) [Anrirelroviral/Protease Inhibitor] Uses HIV Infxn Action Protease inhibitor Dose Adults. Tx naive 2 tab PO daily or 1 tab PO bid Tx experiencedpt 1 tab PO bid (T dose if w/ amprenavir, efavirenz, fosamprenavir, nelfinavir, nevirapine) Peds. 7-15 kg 12/3 mg/kg PO bid 15-40 kg 10/2.5 mg/kg PO bid >40 kg Adult dose w/ food Caution [C, /-] Numerous interactions Contra w/drugs dependent on CYP3A/CYP2D6 (Table VI-8) Disp Tab, soln SE Avoid disulfiram (soln has EtOH), metronidazole GI upset, asthenia, T cholesterol/triglycerides, pancreatitis protease metabolic synd Interactions T Effects Wl clarithromycin, erythromycin T effects OF amiodarone, amprenavir, azole andfungals, bepridil, cisapride, cyclosporine, CCBs, ergot alkaloids, flecainide, flurazepam, HMG-CoA reductase inhibitors, indinavir, lidocaine, meperidine, midazolam, pimozide, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, tacrolimus, terfenadine, triazolam, zolpidem 1 effects Wl barbiturates, carbamazepine, dexamethasone, didanosine, efavirenz, nevirapine, phenytoin, rifabutin, rifampin, St. John s wort 1 effects OF OCPs, warfarin EMS Use andarrhythmics and benzodiazepines... 

A4 Acetaminophen, alfentanil, amiodarone, astemizole, cocaine, cortisol, cyclosporine, dapsone, diazepam, dihydroergotamine, dihydropyridines, diltiazem, ethinyl estradiol, gestodene, indinavir, lidocaine, lovastatin, macrolides, methadone, miconazole, midazolam, mifepristone (RU 486), paclitaxel, progesterone, quinidine, rapamycin, ritonavir, saquinavir, spironolactone, sulfamethoxazole, sufentanil, tacrolimus, tamoxifen, terfenadine, testosterone, tetrahydro-cannabinol, triazolam, troleandomycin, verapamil Barbiturates, carbamazepine, macrolides, glucocorticoids, pioglitazone, phenytoin, rifampin Erythromycin, 613-hydroxy cortisol... 

Aminophylline Aminophylline should not be mixed with acidic drugs, as it becomes precipitated if the pH of the final solution falls below pH 8. Mixture with glucose may increase the pH above 10 where proteins, such as insulin and erythromycin, are unstable. Some drugs that are incompatible with aminophylline include amiodarone, benzylpenicillin potassium, cisatracurium, ceftazidime, ceftriaxone, dobutamine, tetracycline hydrochloride, verapamil hydrochloride, warfarin sodium, and vitamin B and C injection. Alcohol-free theophylline should be stored in amber-colored containers maximum care must be taken to protect it against exposure to light.92-94... 

Heparin and its salts are incompatible with many drugs including alteplase, amikacin sulfate, amiodarone hydrochloride, ampicillin sodium, aprotinin, benzylpenicillin potassium or sodium, cephalothin sodium, ciprofloxacin lactate, cytarabine, dacarbazine, daunorubicin hydrochloride, diazepam, dobutamine hydrochloride, doxorubicin hydrochloride, droperidol, erythromycin lactobionate, gentamicin sulfate, haloperidol lactate, hyaluronidase, hydrocortisone sodium succinate, kanamycin sulfate, methicillin sodium, netilmicin sulfate, some opioid analgesics, oxytetracycline hydrochloride, some phenothiazines, polymyxin B sulfate, streptomycin sulfate, tetracycline hydrochloride, tobramycin sulfate, vancomycin hydrochloride, vinblastine sulfate, cisatracurium besylate, labetalol hydrochloride, nicardipine hydrochloride, cefmetazole, sodium ions, and fat emulsion.110 112... 

CYP3A4 Inhibition Amiodarone, clarithromycin, erythromycin, cimetidine, cyclosporine, fluoxetine fluvoxamine, itraconazole, ketoconazole, nefazodone, verapamil, diltiazem HIV antivirals delaviridine, indanavire, nelfmavire, ritonavire, sequinavire Atorvastatin Lovastatin Simvastatin ... 

May cause QT prolongation with droperidol, erythromycin, amiodarone... 

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