Interactions Flashcards
Insulin
B-blockers, clonidine, and reserpine may mask signs and symptoms of hypoglycaemia; Corticosteroids, estrogens, niacin, phenothiazines, rifampin, and thyroid hormone replacement drugs may ^ insulin requirements; Concurrent use of ACE-Is, alcohol, guanethidine, MAO-Is, octreotde, oral anti diabetic drugs, propranolol, and salicylates may decrease insulin requirements and intensify hypoglycaemic effects of insulin
Baclofen; Skeletal Muscle Relaxant
Additive CNS depression c other CNS depressants, incl. alcohol, antidepressants, antihistamines, opioids, and sedative-hypnotics. Nondepolarising Neuromuscular Drugs: Acetylcholinesterase drugs antagonize the effects of these drugs
Acetaminophen (Tylenol); Nonopioid Analgesic: p-Aminophenol, Nonsalicylate Analgesic
OTC; Preg Cat B
PO anticoagulants can be displaced from protein storage sites; excessive use can ^ risk for bleeding; Use c phenothiazines may produce hypothermia; Use c alcohol, anti epileptic drugs, or isoniazid (INH) can ^ liver toxicity
Acyclovir (Zovirax); Antiviral: Purine Nucleoside Analog
Rx; Preg Cat B
Probenecid will decrease urinary excretion of acyclovir, causing accumulation c potential toxicity; Use c caution c interferon/methotrexate; neurologic reactions may occur
Albuterol (Ventolin)/ Salmeterol (Serevent Discus); Adrenergics: Bronchodilators
Rx; Preg Cat C
Concurrent use c other adrenergic drugs ^ risk for adrenergic side effects; Use c MAO-Is may lead to hypertensive crisis; B blockers may negate bronchodilation effects; May decrease digoxin levels; CV effects are potentiated in pts taking TCAs; Risk for hypokalemia ^ c concurrent use of K+-losing diuretics, which in turn ^ risk for digoxin toxicity; Levalbuterol: Concurrent use or use within 2 wks of TCAs or MAO-Is ^ risk of adverse CV reactions; ^ risk of arrhytmias in pts receiving hydrocarbon inhalational anesthetics or cocaine; Salmeterol: ^ risk of CV effects when used concurrently c atazanivir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir
Tamulosin (Flomax); Antiadrenergics
Rx; Preg Cat B
^ Risk for hypotension when used concurrently c other peripherally acting antiadrenergics such as doxazosin, prazosin, and terazosin; Cimetidine ^ serum levels of tamsulosin, ^ the risk for toxicity
Alprazolam (Xanax)/ Lorazepam (Ativan); Antianxiety/Sedative-Hypnotics; Benzodiazepines
Rx; Preg Cat D
Concurrent use of clarithromycin, hormonal contraceptives, diltiazem, disulfiram, erythromycin, and isoniazid decrease biotransformation of alprazolam and lorazepam; dosage adjustment required; Concurrent use c alcohol, antidepressants, antihistamines, other benzodiazepines, and opioid analgesics ^ CNS depression; May decrease efficacy of barbiturates, carbamazepine, levodopa, and rifampin; Cigarette smoking decreases blood levels and effects. FOOD: Concurrent ingestion of grapefruit juice ^ blood levels
Amitriptyline (Generic); Tricylic Antidepressants
Rx; Preg Cat C/D
Concurrent use of other drugs that compete for cytochrome P-450 (CYP450) 2D6 isoenzyme system, incl. other antidepressants, carbamazepine, flecainide, phenothiazines, propafenone; Concurrent use of other drugs that inhibit CYP enzyme system, incl. amiodarone, cimetidine, quinidine, ritonavir; Concurrent use of MAO-I, SSRI antidepressants may ^ toxicity risk; fluoxetine should be stopped 5 wks prior to starting amitriptyline therapy; Hypertensve crisis possible c clonidine; Blood levels of rifabutin, rifampin, rifapentine, levodopa will be decreased; Concurrent use of moxifloxacin ^ risk for adverse CV effects; ^ Risk of CNS depression c other CNS depressants, incl. alcohol, antihistamines, clonidine, opioids, sedative-hypnotics; Adrenergic and anticholinergic side effects may be ^ c other drugs having anticholinergic properties; Phenothiazines, oral contraceptives ^ serum levels and may cause toxicity; Nicotine alters effects of the TCA
Amlodipine (Norvasc); Antihypertensive: Long-Acting Calcium Channel Blocker
Rx; Preg Cat C
Use c alcohol, general anesthetics, other antihypertensives, fentanyl, nitrates, quinidine can produce additive cardiac and vasodilation effects; Concurrent use of NSAIDs decreases antihypertensive effects of drug; ^ Risk for neurotoxicity c lithium. FOOD: Concurrent consumption of grapefruit juice ^ effects of amlodipine
Amoxicillin (Amoxil, Trimox); Antibiotics: Penicillins (2nd Generation); Aminopenicillins
Rx; Preg Cat B
Antacids, antidiarrheal suspensions, ion-exchange resins decrease PO absorption; Concurrent use of bacteriostatic antibiotics c any penicillin can produce antibiotic antagonism; May ^ effect of warfarin; Probenecid decreases renal excretion and ^ serum amoxicillin levels; Decrease effectiveness of oral contraceptives; Allopurinol may ^ frequency of rash
Aspirin (Acetylsalicylic Acid); Salicylate: Analgesic, Antiinflammatory, Antipyretic, Antiplatelet, NSAID
OTC/Rx for single ingredient formulation; Preg Cat D 1st Trimester
Use c large amounts of antacids best avoided; Buffered aspirin better; Use c ulcerogenic drugs best avoided; ^ Activity of PO anticoagulants, anti diabetic agents; Decreased Uricosuric effects of probenecid, sulfinpyrazone; Decrease PO absorption, uricosuric action of indomethacin; Avoid use c alcohol; Corticosteroids may decrease serum salicylate levels; Use c ACE-Is may decrease their hypotensive effects; Avoid use for 6 wks following varicella live virus vaccine due to possible Reye’s syndrome, esp. in children
Atorvastin (lipitor)/ Pravastatin (Pravachol); HMG-CoA Reductase Inhibitors (also known as “statins”)
Rx; Preg Cat X
Use c erythromycin, gemfibrozil, niacin can invoke rare cases of rhabdomyolysis; Use c oral anticoagulants requires close monitoring of INR/PT; Risk of myopathy ^ c concurrent use of amiodarone, azole antifungals, clarithromycin, clofibrate, cyclosporine, diltiazem, erythromycin, gemfibrozil, nefazodone, nelfinavir, large doses of niacin, ritonavir, saquinavir, telithromycin, and verapamil; Hormonal contraceptives and digoxin levels may ^; Warfarin ^ risk of bleeding; Glyburide and phenytoin ^ levels of both drugs. FOOD: Large quantities of grapefruit juice ^ blood levels and ^ risk of rhabdomyolysis
Azithromycin (Zinthromax); Antibiotics: Macrolide Antibiotics
Rx; Preg Cat B/C
Bacteriostatic antibiotics antagonize effects of bactericidal antibiotics; Concurrent use of warfarin ^ risk of bleeding; Use c carbamazepine, cyclosporine, digoxin, ergot alkaloids, phenytoin, theophylline, triazolam can ^ their toxicity; Use c antacids, dairy products will decrease PO absorption
Lisinopril (Prinivil, Zestril); Antihypertensives, Angiotensin-Converting Enzyme Inhibitors (ACE-Is)
Rx; Preg Cat C during 1st trimester, D during 2nd/3rd trimester
^ Risk for hyperkalemia if used concurrently c K+-sparing diuretics, other antihypertensives, K+ containing salt substitutes, angiotensin II receptor blockers (ARB IIs); Excessive hypotension if used concurrently c diuretics and other antihypotensives; NSAIDs decrease antihypertensive response; Lithium serum levels may be ^ in presence of ACE-Is; Quinapril decrease absorption of doxycycline, fluoroquinolones, tetracyclies; Telmisartan may ^ levels of ramipril and concurrent use should be avoided
BuPROPion (Wellbutrin); Antidepressant; Smoking Cessation Aid
Rx; Preg Cat B
Use c phenelzine ^ toxicity; Use c l-dopa may produce ^ in adverse effects; Use c drugs that decrease seizure threshold best avoided; Use c carbamazepine, cimetidine, phenobarbital, phenytoin requires caution due to ^ metabolism of buPROPion
Cephalexin (Keflex); Antibiotics: Cephalosporins (1st Generation)
Rx; Preg Cat B
Probenecid decreases elimination and ^ serum levels of cephalosporins; Concurrent use of loop diuretics or amino glycosides ^ risk for nephrotoxicity
Celecoxib (Celebrex); Antiinflammatory; Cyclooxygenase-2 (COX-2) Inhibitor, NSAID
Rx; Preg Cat C
Use c aspirin can result in summation of adverse GI effects; Use c ACE-Is can decrease its antihypertensive effects; Use c natriuretic diuretics (ex. furosemide) can decrease their therapeutic effects; Use c calcium carbonate AI/Mg antacids will decrease PO absorption of drugs; Use c lithium, warfarin requires close monitoring when starting of D/C their use; Use c fluconazole may require decrease celecoxib doses due to decreased metabolism of celecoxib. FOOD: High-fat-content meals can decrease celecoxib peak plasma levels from 1-2 hours and ^ total drug absorption
Hydrochlorothiazide (HydroDIURIL); Diuretics (Thiazide); Antihypertensive
Rx; Preg Cat B
^ Digoxin toxicity due to hypokalemia; Use c corticosteroids ^ hypokalemia; Antidiabetic drugs may require dose adjustment; Use c diazoxide can produce significant diabetogenic effects; Use c lithium requires monitoring lithium levels; FOOD: Excessive consumption of liquorice ^ hypokalemia
Famotidine (Pepcid)/ Ranitidine (Zantac); Histamine-2 Antagonists, Histamine-2 Blockers
Rx/OTC; Preg Cat B
Increased serum levels when cimetidine used concurrently c benzodiazepines, B blockers, caffeine, calcium channel blockers, carbamazepine, cyclosporine, dofetilide lidocaine, metformin, metronidazole, mexiletine, nefazodone, pentoxifylline, phenytoin, procainamide, propafenone, quinidine, risperidone, ritonavir, ropinirole, SSRIs, sildeenafil, sulfonylureas, tacrolimus, theophylline, TCAs, venlafaxine, and warfarin. Other H2 blockers are less likely to interact c the above-named drugs; H2 blockers decrease absorption of atazanavir, delavirdine, geftinib, itraconazole, and ketoconazole; Ranitidine ^ absorption of glipiZIDE, midazolam, and triazolam; Ranitidine may ^ effects of warfarin
Ciprofloxacin (Cipro, Cipro XR, Proquin XR); Antibiotics: Fluoroquinolones
Rx; Preg Cat C
Concurrent use c antipsychotics, erythromycin, TCAs ^ risk of prolonged Q-T interval and torsades de pointes (moxifloxacin); Al, Fe, Mg products, sucralfate may decrease PO absorption; Use c theophylline may ^ theophylline toxicity; Probenecid decreases renal excretion; Use c PO anticoagulants requires caution because of possible alteration of interstitial flora and risk for bleeding; Use c caffeine will ^ its effects. FOOD: Food can delay/decrease PO absorption
Citalopram (Celexa); Antidepressants; SSRI
Rx; Preg Cat C
MAY CAUSE SERIOUS POTENTIALLY FATAL REACTIONS IF USED CONCURRENTLY C MAO-Is; allow 14 days between citlopram/escitalopram and MAO-I use; ^ Risk for serotonin syndrome if used concurrently c linezolid, tramadol, triptans; Use cautiously c other centrally acting drugs, incl. alcohol, antihistamines, opioids, sedative-hypnotics; Cimetidine, erythromycin, itraconazole, ketoconazole, omeprazole may ^ levels; Serotoninergic effects may be ^ c concurrent use of lithium; Carbamazepine may decrease levels; May ^ levels of metoprolol; Use cautiously in pts taking TCAs; ^ Risk of bleeding c aspirin, clopidogrel, NSAIDs, or warfarin; ^ Risk for serotonin syndrome c St. John’s wort and SAMe
Clonazepam (Klonopin); Benzodiazepine: Antiepileptic drug
Rx Civ; Preg Cat D
Use c other CNS depressants produces additive effects; Cimetidine, hormonal contraceptives, disulfiram, fluoxetine, isoniazid, ketoconazole, metoprolol, propoxyphene, propanolol, or valproic acid may decrease biotransformation of clonazepam and thus ^ its effects; May ^ serum phenytoin levels; phenytoin may decrease clonazepam; May decrease effectiveness of levodopa; Use c MAO-Is, TCAs produces sedation
