Drug Interaction Report
9 potential interactions and/or warnings found for the following 2 drugs:
- betamethasone / iodixanol / lidocaine
- cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide
Interactions between your drugs
iodixanol tenofovir
Applies to: betamethasone / iodixanol / lidocaine, cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide
GENERALLY AVOID: Concomitant use of intravascular radiocontrast media with other nephrotoxic agents may potentiate the risk of contrast-induced nephropathy and renal impairment. Contrast-induced nephropathy is most commonly defined as an increase in serum creatinine >=0.5 mg/dL or 25% from baseline within 24 to 72 hours of intravascular contrast administration in the absence of alternative etiologies, although nephropathy may occur up to a week after contrast exposure. Pathogenesis has not been fully elucidated, but may involve renal hypoperfusion and ischemia, direct cytotoxicity on tubular epithelial cells, and generation of reactive oxygen species. While the condition is usually transient and asymptomatic, it can be associated with increased risk of renal failure, dialysis, prolonged hospitalization, significant long-term morbidity, and mortality. Patients at increased risk of developing contrast-induced nephropathy include those with diabetes (especially diabetic nephropathy), preexisting renal insufficiency (serum creatinine >1.5 mg/dL or GFR <60 mL/min/1.73 m2), volume depletion (e.g., diuretic use), advanced age (>70 years), congestive heart failure, multiple myeloma, hypoalbuminemia, and concomitant use of nephrotoxic agents (e.g., aminoglycosides; polypeptide, glycopeptide, and polymyxin antibiotics; amphotericin B; aminosalicylates; antiviral/antiretroviral agents such as acyclovir, adefovir, cidofovir, foscarnet, and tenofovir; antineoplastics such as aldesleukin, cisplatin, clofarabine, ifosfamide, streptozocin, and high intravenous dosages of methotrexate; chelating agents such as deferasirox, deferoxamine, edetate disodium, and edetate calcium disodium; immunosuppressants such as cyclosporine, everolimus, sirolimus, and tacrolimus; intravenous bisphosphonates; intravenous pentamidine; high dosages and/or chronic use of nonsteroidal anti-inflammatory agents; gallium nitrate; lithium; penicillamine). The incidence has been reported to be approximately 10% to 30% in patients with risk factors, and as high as 90% in diabetics with chronic kidney disease. Intraarterial administration of contrast media is also associated with increased risk of nephropathy relative to intravenous administration.
MANAGEMENT: Alternative imaging techniques that do not require contrast should be considered in patients who are at increased risk for contrast-induced nephropathy. Otherwise, experts recommend discontinuing other nephrotoxic drugs 1 to 2 days before administration of contrast media, depending on the clinical feasibility of doing so. The smallest effective dose (100 mL or less) of a nonionic, low-osmolar (e.g., iohexol, iomeprol, iopamidol, iopental, iopromide, ioversol) or iso-osmolar (e.g., iodixanol, iotrolan) contrast medium should be used whenever possible, since the risk of nephrotoxicity may be increased with increasing contrast dose, osmolarity, and ionicity. Some studies suggest a lower risk for iso-osmolar contrasts compared to low-osmolar contrasts, although data are limited. Serum creatinine levels should be measured before contrast administration (if procedure is not urgent) and continued for 24 to 48 hours after. In addition, patients should be adequately hydrated with either intravenous normal saline or sodium bicarbonate starting 3 (outpatient) to 6 (inpatient) hours before and continued for 6 to 24 hours after procedure. Oral fluids are also beneficial, but not as effective as intravenous hydration. N-acetylcysteine the day before and day of contrast administration, or theophylline up to 30 minutes before contrast administration, have also been used in high-risk or critically ill patients. Preferably, a nephrologist should be consulted to optimize prophylactic measures for preventing contrast-induced nephropathy in high-risk patients and to guide treatment if the condition occurs. Any repeat procedures with contrast media, if necessary, should not occur until at least 48 to 72 hours after the previous contrast exposure and renal function has fully recovered.
References (7)
- Bennett WM, Porter GA (1990) "Nephrotoxicity of common drugs used by urologists." Urol Clin North Am, 17, p. 145-56
- Bentley ML, Corwin HL, Dasta J (2010) "Drug-induced acute kidney injury in the critically ill adult: recognition and prevention strategies." Crit Care Med, 38(6 Suppl), S169-74
- Marcos LA, Camins BC, Ritchie DJ, Casabar E, Warren DK (2012) "Acute renal insufficiency during telavancin therapy in clinical practice." J Antimicrob Chemother, 67, p. 723-6
- Dubrovskaya Y, Prasad N, Lee Y, Esaian D, Figueroa DA, Tam VH (2015) "Risk factors for nephrotoxicity onset associated with polymyxin B therapy." J Antimicrob Chemother, 70, p. 1903-7
- Bansal R, Aflieco F, Kaplan AA (2016) Contrast-Induced Nephropathy. http://emedicine.medscape.com/article/246751-overview
- van den Berk G, Tonino S, de Fijter C, Smit W, Schultz MJ (2005) "Bench-to-bedside review: Preventative measures for contrast-induced nephropathy in critically ill patients." Crit Care, 9, p. 361-70
- Kellum JA, Leblanc M, Venkataraman R (2008) "Acute renal failure." BMJ Clin Evid, 9, p. 2001
lidocaine cobicistat
Applies to: betamethasone / iodixanol / lidocaine, cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide
MONITOR: Coadministration with cobicistat may increase the plasma concentrations of lidocaine. The proposed mechanism involves cobicistat inhibition of CYP450 3A4-mediated metabolism of lidocaine. The interaction has not been specifically studied, but could conceivably lead to serious and/or life-threatening reactions including cardiac arrhythmias and other toxicities if levels are significantly increased.
MANAGEMENT: Caution is advised if cobicistat must be used concomitantly with lidocaine. Pharmacologic response and plasma lidocaine levels should be monitored more closely whenever cobicistat is added to or withdrawn from therapy, and the lidocaine dosage adjusted as necessary.
References (2)
- Cerner Multum, Inc. "UK Summary of Product Characteristics."
- (2015) "Product Information. Evotaz (atazanavir-cobicistat)." Bristol-Myers Squibb
betamethasone cobicistat
Applies to: betamethasone / iodixanol / lidocaine, cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide
MONITOR: Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations and pharmacologic effects of corticosteroids, which are primarily metabolized by the isoenzyme. The interaction has been reported with potent inhibitors such as clarithromycin, erythromycin, itraconazole, nefazodone, cobicistat, and ritonavir during concomitant use of various corticosteroids, including inhaled, nasal, and ophthalmic formulations. Systemic corticosteroid adverse effects may occur following intensive or long-term continuous ophthalmic corticosteroid therapy. Cushing's syndrome and adrenal insufficiency have been attributed to the interaction.
MANAGEMENT: The possibility of increased corticosteroid effects should be considered during coadministration with potent and moderate CYP450 3A4 inhibitors. Some authorities advise against concomitant use unless the potential benefit outweighs the risk. If the combination is considered necessary, a lower dosage of the corticosteroid may be required. When indicated for intranasal or inhalational use, alternative corticosteroids such as beclomethasone, which is less dependent on CYP450 3A4 metabolism, should be considered, particularly if long term treatment is required. Patients should be monitored for signs and symptoms of hypercorticism such as acne, striae, thinning of the skin, easy bruising, moon facies, dorsocervical "buffalo" hump, truncal obesity, increased appetite, acute weight gain, edema, hypertension, hirsutism, hyperhidrosis, proximal muscle wasting and weakness, glucose intolerance, exacerbation of preexisting diabetes, depression, and menstrual disorders. Other systemic glucocorticoid effects may include adrenal suppression, immunosuppression, posterior subcapsular cataracts, glaucoma, bone loss, and growth retardation in children and adolescents. Following extensive use with a potent CYP450 3A4 inhibitor, a progressive dosage reduction may be required over a longer period if the corticosteroid is to be withdrawn from therapy, as there may be a significant risk of adrenal suppression. Signs and symptoms of adrenal insufficiency include anorexia, hypoglycemia, nausea, vomiting, weight loss, muscle wasting, fatigue, weakness, dizziness, postural hypotension, depression, and adrenal crisis manifested as inability to respond to stress (e.g., illness, infection, surgery, trauma).
References (29)
- Zurcher RM, Frey BM, Frey FJ (1989) "Impact of ketoconazole on the metabolism of prednisolone." Clin Pharmacol Ther, 45, p. 366-72
- Yamashita SK, Ludwig EA, Middleton E Jr, Jusko WJ (1991) "Lack of pharmacokinetic and pharmacodynamic interactions between ketoconazole and prednisolone." Clin Pharmacol Ther, 49, p. 558-70
- Ulrich B, Frey FJ, Speck RF, Frey BM (1992) "Pharmacokinetics/pharmacodynamics of ketoconazole-prednisolone interaction." J Pharmacol Exp Ther, 260, p. 487-90
- Kandrotas RJ, Slaughter RL, Brass C, Jusko WJ (1987) "Ketoconazole effects on methylprednisolone disposition and their joint suppression of endogenous cortisol." Clin Pharmacol Ther, 42, p. 465-70
- Glynn AM, Slaughter RL, Brass C, et al. (1986) "Effects of ketoconazole on methylprednisolone pharmacokinetics and cortisol secretion." Clin Pharmacol Ther, 39, p. 654-9
- Itkin IH, Menzel ML (1970) "The use of macrolide antibiotic substances in the treatment of asthma." J Allergy Clin Immunol, 45, p. 146-62
- LaForce CF, Szefler SJ, Miller MF, Ebling W, Brenner M (1983) "Inhibition of methylprednisolone elimination in the presence of erythromycin therapy." J Allergy Clin Immunol, 72, p. 34-9
- Finkenbine RD, Frye MD (1998) "Case of psychosis due to prednisone-clarithromycin interaction." Gen Hosp Psychiat, 20, p. 325-6
- Varis T, Kaukonen KM, Kivisto KT, Neuvonen PJ (1998) "Plasma concentrations and effects of oral methylprednisolone are considerably increased by itraconazole." Clin Pharmacol Ther, 64, p. 363-8
- Hillebrand-Haverkort ME, Prummel MF, ten Veen JH (1999) "Ritonavir-induced Cushing's syndrome in a patient treated with nasal fluticasone." AIDS, 13, p. 1803
- Varis T, Kivisto KT, Neuvonen PJ (2000) "The effect of itraconazole on the pharmacokinetics and pharmacodynamics of oral prednisolone." Eur J Clin Pharmacol, 56, p. 57-60
- Varis T, Backman JT, Kivisto KT, Neuvonen PJ (2000) "Diltiazem and mibefradil increase the plasma concentrations and greatly enhance the adrenal-suppressant effect of oral methylprednisolone." Clin Pharmacol Ther, 67, p. 215-21
- Garey KW, Rubinstein I, Gotfried MH, Khan IJ, Varma S, Danziger LH (2000) "Long-term clarithromycin decreases prednisone requirements in elderly patients with prednisone-dependent asthma." Chest, 118, p. 1826-7
- Lebrun-Vignes B, Archer VC, Diquest B, et al. (2001) "Effect of itraconazole on the pharmacokinetics of prednisolone and methylprednisolone and cortisol secretion in healthy subjects." Br J Clin Pharmacol, 51, p. 443-50
- Couturier J, Steele M, Hussey L, Pawliuk G (2001) "Steroid-induced mania in an adolescent: risk factors and management." Can J Clin Pharmacol, 8, p. 109-12
- Gupta SK, Dube MP (2002) "Exogenous Cushing syndrome mimicking human immunodeficiency virus lipodystrophy." Clin Infect Dis, 35, E69-71
- Raaska K, Niemi M, Neuvonen M, Neuvonen PJ, Kivisto KT (2002) "Plasma concentrations of inhaled budesonide and its effects on plasma cortisol are increased by the cytochrome P4503A4 inhibitor itraconazole." Clin Pharmacol Ther, 72, p. 362-369
- Main KM, Skov M, Sillesen IB, et al. (2002) "Cushing's syndrome due to pharmacological interaction in a cystic fibrosis patient." Acta Paediatr, 91, p. 1008-11
- Skov M, Main KM, Sillesen IB, Muller J, Koch C, Lanng S (2002) "Iatrogenic adrenal insufficiency as a side-effect of combined treatment of itraconazole and budesonide." Eur Respir J, 20, p. 127-33
- Kotlyar M, Brewer ER, Golding M, Carson SW (2003) "Nefazodone inhibits methylprednisolone disposition and enhances its adrenal-suppressant effect." J Clin Psychopharmacol, 23, p. 652-6
- Bolland MJ, Bagg W, Thomas MG, Lucas JA, Ticehurst R, Black PN (2004) "Cushing's syndrome due to interaction between inhaled corticosteroids and itraconazole." Ann Pharmacother, 38, p. 46-9
- Edsbacker S, Andersson T (2004) "Pharmacokinetics of budesonide (Entocort EC) capsules for Crohn's disease." Clin Pharmacokinet, 43, p. 803-21
- Samaras K, Pett S, Gowers A, McMurchie M, Cooper DA (2005) "Iatrogenic Cushing's syndrome with osteoporosis and secondary adrenal failure in HIV-infected patients receiving inhaled corticosteroids and ritonavir-boosted protease inhibitors: six cases." J Clin Endocrinol Metab, 90, p. 4394-8
- Soldatos G, Sztal-Mazer S, Woolley I, Stockigt J (2005) "Exogenous glucocorticoid excess as a result of ritonavir-fluticasone interaction." Intern Med J, 35, p. 67-8
- Penzak SR, Formentini E, Alfaro RM, Long M, Natarajan V, Kovacs J (2005) "Prednisolone pharmacokinetics in the presence and absence of ritonavir after oral prednisone administration to healthy volunteers." J Acquir Immune Defic Syndr, 40, p. 573-80
- EMEA. European Medicines Agency (2007) EPARs. European Union Public Assessment Reports. http://www.ema.europa.eu/ema/index.jsp?curl=pages/includes/medicines/medicines_landingpage.jsp&mid
- Bhumbra NA, Sahloff EG, Oehrtman SJ, Horner JM (2007) "Exogenous Cushing syndrome with inhaled fluticasone in a child receiving lopinavir/ritonavir." Ann Pharmacother, 41, p. 1306-9
- Busse KH, Formentini E, Alfaro RM, Kovacs JA, Penzak SR (2008) "Influence of antiretroviral drugs on the pharmacokinetics of prednisolone in HIV-infected individuals." J Acquir Immune Defic Syndr, 48, p. 561-6
- Agencia Española de Medicamentos y Productos Sanitarios Healthcare (2008) Centro de información online de medicamentos de la AEMPS - CIMA. https://cima.aemps.es/cima/publico/home.html
tenofovir cobicistat
Applies to: cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide, cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide
MONITOR: Concomitant use of tenofovir with cobicistat may increase the risk for tenofovir-related renal adverse effects, including renal impairment, renal failure, elevated creatinine, and Fanconi syndrome. The mechanism of this interaction has not been described. Cobicistat may decrease estimated creatinine clearance via inhibition of tubular secretion of creatinine; however, renal glomerular function does not appear to be affected. When given concomitantly with cobicistat, the systemic exposure (AUC) and trough plasma concentrations (Cmin) of tenofovir was also increased by 23% and 55%, respectively. However, data are lacking to determine whether concomitant use of tenofovir with cobicistat-containing regimens is associated with a greater risk of renal complications compared with regimens that do not include cobicistat.
MANAGEMENT: Initiation of cobicistat or cobicistat-containing regimens is not recommended in patients with CrCl less than 70 mL/min if any coadministered medicine requires dose adjustment based on renal function (including tenofovir), or is nephrotoxic. If concomitant therapy is necessary, monitoring of renal function is recommended, particularly in patients with risk factors for renal impairment.
References (4)
- (2001) "Product Information. Viread (tenofovir)." Gilead Sciences
- Cerner Multum, Inc. "UK Summary of Product Characteristics."
- Cerner Multum, Inc. "Australian Product Information."
- (2014) "Product Information. Tybost (cobicistat)." Gilead Sciences
emtricitabine cobicistat
Applies to: cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide, cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide
GENERALLY AVOID: Cobicistat may increase the plasma concentrations of antiretroviral agents. The plasma concentrations of cobicistat may also be increased or reduced in the presence of antiretroviral agents. The proposed mechanism is cobicistat inhibition of the CYP450 3A4 isoenzyme, of which antiretroviral agents may be substrates, and the inhibition or induction of CYP450 3A4 by concomitant antiretroviral medications. Cobicistat is a mechanism-based inhibitor and substrate of CYP450 3A4 with no antiretroviral activity of its own. Rather, it is indicated in its capacity as a pharmacokinetic booster of CYP450 3A4 to increase the systemic exposure of some antiretroviral medications such as atazanavir, darunavir, and elvitegravir, which are substrates of this isoenzyme. Concomitant use of other antiretroviral agents with cobicistat may also increase the plasma levels and risk of side effects associated with these medicines. In contrast, concomitant use of cobicistat-boosted atazanavir or darunavir with CYP450 3A4 inducers nevirapine, etravirine, or efavirenz may reduce the plasma concentrations of cobicistat, darunavir, and atazanavir, leading to a potential loss of therapeutic effect and development of resistance to darunavir and atazanavir. Pharmacokinetic data are not available.
MANAGEMENT: Cobicistat is not intended for use with more than one antiretroviral medication that requires pharmacokinetic enhancement, such as two protease inhibitors or elvitegravir in combination with a protease inhibitor. In addition, cobicistat should not be used concomitantly with ritonavir due to their similar effects on CYP450 3A4. According to some authorities, use of the antiretroviral combinations of atazanavir-cobicistat or darunavir-cobicistat concomitantly with the CYP450 3A4 inducers efavirenz, etravirine, or nevirapine is also not recommended. Other authorities consider the administration of atazanavir-cobicistat with efavirenz or nevirapine to be contraindicated. Since dosing recommendations have only been established for a number of antiretroviral medications, product labeling and current antiretroviral treatment guidelines should be consulted.
References (10)
- (2001) "Product Information. Viramune (nevirapine)." Boehringer-Ingelheim
- (2001) "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals
- Cerner Multum, Inc. "UK Summary of Product Characteristics."
- (2006) "Product Information. Prezista (darunavir)." Ortho Biotech Inc
- (2008) "Product Information. Intelence (etravirine)." Ortho Biotech Inc
- Cerner Multum, Inc. "Australian Product Information."
- (2012) "Product Information. Stribild (cobicistat/elvitegravir/emtricitabine/tenofov)." Gilead Sciences
- (2014) "Product Information. Tybost (cobicistat)." Gilead Sciences
- (2014) "Product Information. Prezcobix (cobicistat-darunavir)." Janssen Pharmaceuticals
- (2015) "Product Information. Evotaz (atazanavir-cobicistat)." Bristol-Myers Squibb
Drug and food interactions
lidocaine food
Applies to: betamethasone / iodixanol / lidocaine
MONITOR: Grapefruit and grapefruit juice may increase the plasma concentrations of lidocaine, which is primarily metabolized by the CYP450 3A4 and 1A2 isoenzymes to active metabolites (monoethylglycinexylidide (MEGX) and glycinexylidide). The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit juice but has been reported with oral and/or intravenous lidocaine and potent CYP450 3A4 inhibitor, itraconazole, as well as moderate CYP450 3A4 inhibitor, erythromycin. A pharmacokinetic study of 9 healthy volunteers showed that the administration of lidocaine oral (1 mg/kg single dose) with itraconazole (200 mg daily) increased lidocaine systemic exposure (AUC) and peak plasma concentration (Cmax) by 75% and 55%, respectively. However, no changes were observed in the pharmacokinetics of the active metabolite MEGX. In the same study, when the moderate CYP450 3A4 inhibitor erythromycin (500 mg three times a day) was administered, lidocaine AUC and Cmax increased by 60% and 40%, respectively. By contrast, when intravenous lidocaine (1.5 mg/kg infusion over 60 minutes) was administered on the fourth day of treatment with itraconazole (200 mg once a day) no changes in lidocaine AUC or Cmax were observed. However, when lidocaine (1.5 mg/kg infusion over 60 minutes) was coadministered with erythromycin (500 mg three times a day) in the same study, the AUC and Cmax of the active metabolite MEGX significantly increased by 45-60% and 40%, respectively. The observed differences between oral and intravenous lidocaine when coadministered with CYP450 3A4 inhibitors may be attributed to inhibition of CYP450 3A4 in both the gastrointestinal tract and liver affecting oral lidocaine to a greater extent than intravenous lidocaine. In general, the effects of grapefruit products are concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. While the clinical significance of this interaction is unknown, increased exposure to lidocaine may lead to serious and/or life-threatening reactions including respiratory depression, convulsions, bradycardia, hypotension, arrhythmias, and cardiovascular collapse.
MONITOR: Certain foods and behaviors that induce CYP450 1A2 may reduce the plasma concentrations of lidocaine. The proposed mechanism is induction of hepatic CYP450 1A2, one of the isoenzymes responsible for the metabolic clearance of lidocaine. Cigarette smoking is known to be a CYP450 1A2 inducer. In one pharmacokinetic study of 4 smokers and 5 non-smokers who received 2 doses of lidocaine (100 mg IV followed by 100 mg orally after a 2-day washout period), the smokers' systemic exposure (AUC) of oral lidocaine was 68% lower than non-smokers. The AUC of IV lidocaine was only 9% lower in smokers compared with non-smokers. Other CYP450 1A2 inducers include cruciferous vegetables (e.g., broccoli, brussels sprouts) and char-grilled meat. Therefore, eating large or variable amounts of these foods could also reduce lidocaine exposure. The clinical impact of smoking and/or the ingestion of foods that induce CYP450 1A2 on lidocaine have not been studied, however, a loss of efficacy may occur.
MANAGEMENT: Caution is recommended if lidocaine is to be used in combination with grapefruit and grapefruit juice. Monitoring for lidocaine toxicity and plasma lidocaine levels may also be advised, and the lidocaine dosage adjusted as necessary. Patients who smoke and/or consume cruciferous vegetables may be monitored for reduced lidocaine efficacy.
References (7)
- Huet PM, LeLorier J (1980) "Effects of smoking and chronic hepatitis B on lidocaine and indocyanine green kinetics" Clin Pharmacol Ther, 28, p. 208-15
- (2024) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hospira Inc.
- (2015) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hospira Healthcare Corporation
- (2022) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hameln Pharma Ltd
- (2022) "Product Information. Xylocaine HCl (lidocaine)." Aspen Pharmacare Australia Pty Ltd
- Isohanni MH, Neuvonen PJ, Olkkola KT (2024) Effect of erythromycin and itraconazole on the pharmacokinetics of oral lignocaine https://pubmed.ncbi.nlm.nih.gov/10193676/
- Isohanni MH, Neuvonen PJ, Olkkola KT (2024) Effect of erythromycin and itraconazole on the pharmacokinetics of intravenous lignocaine https://pubmed.ncbi.nlm.nih.gov/9832299/
elvitegravir food
Applies to: cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide
ADJUST DOSING INTERVAL: Food enhances the oral bioavailabilities of both elvitegravir and tenofovir. When a single dose of cobicistat/elvitegravir/emtricitabine/tenofovir (trade name Stribild) was given with a light meal (approximately 373 kcal; 20% fat), mean elvitegravir and tenofovir systemic exposures (AUCs) increased by 34% and 24%, respectively, relative to fasting conditions. When administered with a high-fat meal (approximately 800 kcal; 50% fat), the mean AUC of elvitegravir and tenofovir increased by 87% and 23%, respectively, relative to fasting conditions. The alterations in mean AUCs of cobicistat and emtricitabine were not clinically significant with either the light or high-fat meal.
MANAGEMENT: Cobicistat/elvitegravir/emtricitabine/tenofovir as a fixed-dose preparation should be administered once daily with food. Elvitegravir as a single-ingredient preparation should also be administered once daily with food.
References (2)
- (2012) "Product Information. Stribild (cobicistat/elvitegravir/emtricitabine/tenofov)." Gilead Sciences
- (2014) "Product Information. Vitekta (elvitegravir)." Gilead Sciences
lidocaine food
Applies to: betamethasone / iodixanol / lidocaine
MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.
MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.
References (4)
- (2024) "Product Information. Cytisine (cytisinicline)." Consilient Health Ltd
- jeong sh, Newcombe D, sheridan j, Tingle M (2015) "Pharmacokinetics of cytisine, an a4 b2 nicotinic receptor partial agonist, in healthy smokers following a single dose." Drug Test Anal, 7, p. 475-82
- Vaughan DP, Beckett AH, Robbie DS (1976) "The influence of smoking on the intersubject variation in pentazocine elimination." Br J Clin Pharmacol, 3, p. 279-83
- Zevin S, Benowitz NL (1999) "Drug interactions with tobacco smoking: an update" Clin Pharmacokinet, 36, p. 425-38
tenofovir food
Applies to: cobicistat / elvitegravir / emtricitabine / tenofovir alafenamide
Food enhances the oral absorption and bioavailability of tenofovir, the active entity of tenofovir disoproxil fumarate. According to the product labeling, administration of the drug following a high-fat meal increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of tenofovir by approximately 14% and 40%, respectively, compared to administration in the fasting state. However, administration with a light meal did not significantly affect the pharmacokinetics of tenofovir compared to administration in the fasting state. Food delays the time to reach tenofovir Cmax by approximately 1 hour. Tenofovir disoproxil fumarate may be administered without regard to meals.
References (1)
- (2001) "Product Information. Viread (tenofovir)." Gilead Sciences
Therapeutic duplication warnings
No duplication warnings were found for your selected drugs.
Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.
Drug Interaction Classification
| Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
| Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
| Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. | |
| No interaction information available. |
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