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Drug Interactions between Decadron with Xylocaine and emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

lidocaine ritonavir

Applies to: Decadron with Xylocaine (dexamethasone / lidocaine) and emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

MONITOR: Coadministration with moderate and potent inhibitors of CYP450 3A4 may increase the plasma concentrations of lidocaine, which is primarily metabolized by CYP450 3A4 and 1A2 isoenzymes to active metabolites (monoethylglycinexylidide (MEGX) and glycinexylidide). In addition, antiarrhythmic calcium channel blockers that also inhibit CYP450 3A4 (e.g., diltiazem, verapamil) may have additive negative inotropic effects on the heart when coadministered with lidocaine. A pharmacokinetic study of 9 healthy volunteers showed that the administration of lidocaine oral (1 mg/kg single dose) with itraconazole (200 mg daily), a combined potent CYP450 3A4 and P-gp inhibitor, 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. 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.

MANAGEMENT: Caution and clinical monitoring are advised if lidocaine must be used concomitantly with moderate and potent CYP450 3A4 inhibitors. Monitoring of pharmacologic response and plasma lidocaine levels may be advised whenever a potent CYP450 3A4 inhibitor is added to or withdrawn from therapy, and the lidocaine dosage adjusted as necessary.

References (6)
  1. (2024) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hospira Inc.
  2. (2015) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hospira Healthcare Corporation
  3. (2022) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hameln Pharma Ltd
  4. (2022) "Product Information. Xylocaine HCl (lidocaine)." Aspen Pharmacare Australia Pty Ltd
  5. 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/
  6. 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/

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Moderate

dexAMETHasone ritonavir

Applies to: Decadron with Xylocaine (dexamethasone / lidocaine) and emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

GENERALLY AVOID: Coadministration with protease inhibitors may increase the plasma concentration and pharmacologic effects of dexamethasone. The proposed mechanism is protease inhibitor-mediated inhibition of CYP450 3A4, the isoenzyme involved in the metabolic clearance of dexamethasone. Ritonavir has been reported to increase dexamethasone systemic exposure (AUC) by more than threefold. In one case report, an HIV patient who had been receiving long-term dexamethasone therapy for thrombotic thrombocytopenia purpura developed spinal epidural lipomatosis four months following the initiation of ritonavir. Although the patient was already cushingoid as a result of chronic dexamethasone administration, he did not have symptoms of myelopathy until after ritonavir was added. The effect of dexamethasone on the clearance of protease inhibitors has not been established. Theoretically, plasma levels of protease inhibitors may decrease due to dexamethasone induction of their metabolism by CYP450 3A4. This may lead to a loss of therapeutic effect and development of resistance to protease inhibitor-containing antiretroviral regimens; however, data are not available. These interactions may also be seen with cobicistat, a potent CYP450 3A4 inhibitor that solely acts as a pharmacokinetic booster in antiretroviral treatment regimen; however, data are not available.

MONITOR: Corticosteroids such as dexamethasone may cause hypokalemia and potentiate the risk of QT and/or PR interval prolongation associated with the use of certain protease inhibitors such as atazanavir, lopinavir-ritonavir, and saquinavir-ritonavir. The risk of torsade de pointes arrhythmia, bradycardia, and heart block may be increased.

MANAGEMENT: Caution is advised if dexamethasone must be used concomitantly with protease inhibitors or cobicistat. Some authorities advise against concomitant use unless the potential benefit outweighs the risk. Adrenal function should be monitored regularly during chronic use of these agents, and dexamethasone dosage adjusted as necessary. Patients should be monitored for symptoms of hypercorticism (e.g., acne, easy bruising, moon face, edema, hirsutism, buffalo hump, skin striae, glucose intolerance, and irregular menstruations), immunosuppression, and osteoporosis. In addition, it may be appropriate to monitor patients for potentially reduced antiretroviral response following initiation or any dosage increase of dexamethasone. Serum potassium and ECG monitoring should also be considered during coadministration of dexamethasone with certain protease inhibitors in accordance with the product labeling.

References (3)
  1. (2001) "Product Information. Norvir (ritonavir)." Abbott Pharmaceutical
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  3. Cerner Multum, Inc. "Australian Product Information."

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Moderate

dexAMETHasone lopinavir

Applies to: Decadron with Xylocaine (dexamethasone / lidocaine) and emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

MONITOR: Coadministration of lopinavir-ritonavir with inducers of CYP450 3A4 may decrease the plasma concentrations of lopinavir, which is primarily metabolized by the isoenzyme. Clinical studies have shown that potent CYP450 3A4 inducers such as rifampin and phenytoin can significantly alter the plasma concentrations of lopinavir, possibly by overriding some of the inhibiting effects of ritonavir and enhancing the clearance of both lopinavir and ritonavir. In 22 healthy, HIV-negative subjects, administration of lopinavir-ritonavir (400 mg-100 mg twice daily for 20 days) with rifampin (600 mg once daily for 10 days) decreased lopinavir peak plasma concentration (Cmax), systemic exposure (AUC) and trough plasma concentration (Cmin) by 55%, 75% and 99%, respectively. In another study of 12 healthy volunteers, coadministration of lopinavir-ritonavir (400 mg-100 mg twice daily for 22 days) and phenytoin (300 mg once daily on days 11 through 22) resulted in decreases in Cmax, AUC and Cmin of lopinavir by 24%, 33% and 46%, respectively. Ritonavir Cmax, AUC and Cmin were also reduced by 20%, 28% and 47%, respectively, although only the change in Cmin was statistically significant. The extent to which other, less potent inducers of CYP450 3A4 may interact with lopinavir-ritonavir is unknown. In addition, when two or more medications with similar adverse effect profiles are given concurrently, the likelihood of experiencing these adverse reactions may be increased. For example, coadministration with other agents that can prolong the QT interval (e.g., apalutamide, encorafenib, enzalutamide) may result in additive effects and an increased risk of ventricular arrhythmias like torsade de pointes.

MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiretroviral drug levels, caution is advised if lopinavir-ritonavir is prescribed with CYP450 3A4 inducers. Close clinical and laboratory monitoring of antiretroviral response is recommended. If the CYP450 3A4 inducer also carries a risk of prolonging the QT interval, then obtaining more frequent electrocardiograms (ECGs) to monitor the QT interval may be advisable. Patients should be counseled to seek immediate medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, syncope, palpitations, irregular heartbeat, and/or shortness of breath. The prescribing information for the concomitant CYP450 3A4 inducers should be consulted for specific recommendations.

References (5)
  1. Brooks J, Daily J, Schwamm L (1997) "Protease inhibitors and anticonvulsants." AIDS Clin Care, 9, 87,90
  2. Durant J, Clevenbergh P, Garraffo R, Halfon P, Icard S, DelGiudice P, Montagne N, Schapiro JM, Dellamonica P (2000) "Importance of protease inhibitor plasma levels in HIV-infected patients treated with genotypic-guided therapy: pharmacological data from the Viradapt Study." Aids, 14, p. 1333-9
  3. (2001) "Product Information. Kaletra (lopinavir-ritonavir)." Abbott Pharmaceutical
  4. Liedtke MD, Lockhart SM, Rathbun RC (2004) "Anticonvulsant and antiretroviral interactions." Ann Pharmacother, 38, p. 482-9
  5. Lim ML, Min SS, Eron JJ, et al. (2004) "Coadministration of lopinavir/ritonavir and phenytoin results in two-way drug interaction through cytochrome P-450 induction." J Acquir Immune Defic Syndr, 36, p. 1034-40

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Moderate

ritonavir tenofovir

Applies to: emtricitabine / lopinavir / ritonavir / tenofovir disoproxil and emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

MONITOR: Coadministration with ritonavir, with or without lopinavir, has been suggested in postmarketing reports to increase the proximal tubular intracellular concentrations of tenofovir and potentiate the risk of tenofovir-induced nephrotoxicity. The proposed mechanism is ritonavir inhibition of tenofovir renal tubular secretion into the urine via multidrug resistance protein MRP2. Analysis of data from a compassionate access study in which 271 patients with advanced HIV disease received the combination for a mean duration of 63 weeks revealed no clinically significant nephrotoxicity associated with coadministration. However, there have been case reports of renal failure associated with acute tubular necrosis, Fanconi's syndrome, and nephrogenic diabetes insipidus in patients treated with tenofovir disoproxil fumarate in combination with ritonavir. Some patients had incomplete recovery of renal function more than a year after cessation of tenofovir therapy. Ritonavir given in combination with lopinavir has also been reported to modestly increase the plasma concentrations of tenofovir. In contrast, both slight decreases and no change in lopinavir and ritonavir concentrations have been reported.

MANAGEMENT: Caution is advised if tenofovir disoproxil fumarate is prescribed with ritonavir. Renal function should be monitored regularly, including surveillance for signs of tubulopathy such as glycosuria, acidosis, increases in serum creatinine level, electrolyte disturbances (e.g., hypokalemia, hypophosphatemia), and proteinuria. The same precaution may be applicable during therapy with other protease inhibitors based on their similar pharmacokinetic profile, although clinical data are lacking. Nelfinavir reportedly does not alter the pharmacokinetics of tenofovir, or vice versa. Tenofovir administration should be discontinued promptly if nephropathy develops.

References (8)
  1. (2001) "Product Information. Viread (tenofovir)." Gilead Sciences
  2. Verhelst D, Monge M, Meynard JL, et al. (2002) "Fanconi syndrome and renal failure induced by tenofovir: A first case report." Am J Kidney Dis, 40, p. 1331-3
  3. Creput C, Gonzalez-Canali G, Hill G, Piketty C, Kazatchkine M, Nochy D (2003) "Renal lesions in HIV-1-positive patient treated with tenofovir." AIDS, 17, p. 935-7
  4. Karras A, Lafaurie M, Furco A, et al. (2003) "Tenofovir-related nephrotoxicity in human immunodeficiency virus-infected patients: three cases of renal failure, fanconi syndrome, and nephrogenic diabetes insipidus." Clin Infect Dis, 36, p. 1070-3
  5. Kearney BP, Mittan A, Sayre J, et al. (2003) Pharmacokinetic drug interaction and long term safety profile of tenofovir DF and lopinavir/ritonavir. http://www.icaac.org/ICAAC.asp
  6. Rollot F, Nazal EM, Chauvelot-Moachon L, et al. (2003) "Tenofovir-related fanconi syndrome with nephrogenic diabetes insipidus in a patient with acquired immunodeficiency syndrome: the role of lopinavir-ritonavir-Didanosine." Clin Infect Dis, 37, E174-6
  7. Zimmermann AE, Pizzoferrato T, Bedford J, Morris A, Hoffman R, Braden G (2006) "Tenofovir-associated acute and chronic kidney disease: a case of multiple drug interactions." Clin Infect Dis, 42, p. 283-90
  8. Kapadia J, Shah S, Desai C, et al. (2013) "Tenofovir induced Fanconi syndrome: a possible pharmacokinetic interaction." Indian J Pharmacol, 45, p. 191-2

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Moderate

lopinavir tenofovir

Applies to: emtricitabine / lopinavir / ritonavir / tenofovir disoproxil and emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

MONITOR: Coadministration with ritonavir, with or without lopinavir, has been suggested in postmarketing reports to increase the proximal tubular intracellular concentrations of tenofovir and potentiate the risk of tenofovir-induced nephrotoxicity. The proposed mechanism is ritonavir inhibition of tenofovir renal tubular secretion into the urine via multidrug resistance protein MRP2. Analysis of data from a compassionate access study in which 271 patients with advanced HIV disease received the combination for a mean duration of 63 weeks revealed no clinically significant nephrotoxicity associated with coadministration. However, there have been case reports of renal failure associated with acute tubular necrosis, Fanconi's syndrome, and nephrogenic diabetes insipidus in patients treated with tenofovir disoproxil fumarate in combination with ritonavir. Some patients had incomplete recovery of renal function more than a year after cessation of tenofovir therapy. Ritonavir given in combination with lopinavir has also been reported to modestly increase the plasma concentrations of tenofovir. In contrast, both slight decreases and no change in lopinavir and ritonavir concentrations have been reported.

MANAGEMENT: Caution is advised if tenofovir disoproxil fumarate is prescribed with ritonavir. Renal function should be monitored regularly, including surveillance for signs of tubulopathy such as glycosuria, acidosis, increases in serum creatinine level, electrolyte disturbances (e.g., hypokalemia, hypophosphatemia), and proteinuria. The same precaution may be applicable during therapy with other protease inhibitors based on their similar pharmacokinetic profile, although clinical data are lacking. Nelfinavir reportedly does not alter the pharmacokinetics of tenofovir, or vice versa. Tenofovir administration should be discontinued promptly if nephropathy develops.

References (8)
  1. (2001) "Product Information. Viread (tenofovir)." Gilead Sciences
  2. Verhelst D, Monge M, Meynard JL, et al. (2002) "Fanconi syndrome and renal failure induced by tenofovir: A first case report." Am J Kidney Dis, 40, p. 1331-3
  3. Creput C, Gonzalez-Canali G, Hill G, Piketty C, Kazatchkine M, Nochy D (2003) "Renal lesions in HIV-1-positive patient treated with tenofovir." AIDS, 17, p. 935-7
  4. Karras A, Lafaurie M, Furco A, et al. (2003) "Tenofovir-related nephrotoxicity in human immunodeficiency virus-infected patients: three cases of renal failure, fanconi syndrome, and nephrogenic diabetes insipidus." Clin Infect Dis, 36, p. 1070-3
  5. Kearney BP, Mittan A, Sayre J, et al. (2003) Pharmacokinetic drug interaction and long term safety profile of tenofovir DF and lopinavir/ritonavir. http://www.icaac.org/ICAAC.asp
  6. Rollot F, Nazal EM, Chauvelot-Moachon L, et al. (2003) "Tenofovir-related fanconi syndrome with nephrogenic diabetes insipidus in a patient with acquired immunodeficiency syndrome: the role of lopinavir-ritonavir-Didanosine." Clin Infect Dis, 37, E174-6
  7. Zimmermann AE, Pizzoferrato T, Bedford J, Morris A, Hoffman R, Braden G (2006) "Tenofovir-associated acute and chronic kidney disease: a case of multiple drug interactions." Clin Infect Dis, 42, p. 283-90
  8. Kapadia J, Shah S, Desai C, et al. (2013) "Tenofovir induced Fanconi syndrome: a possible pharmacokinetic interaction." Indian J Pharmacol, 45, p. 191-2

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Minor

lidocaine dexAMETHasone

Applies to: Decadron with Xylocaine (dexamethasone / lidocaine) and Decadron with Xylocaine (dexamethasone / lidocaine)

Coadministration with inducers of CYP450 1A2 and/or 3A4 may decrease the plasma concentrations of lidocaine, which is primarily metabolized by these isoenzymes. In four healthy volunteers (2 smokers and 2 nonsmokers), administration of a single 400 mg oral dose of lidocaine following pretreatment with the CYP450 inducer phenobarbital (15 mg/day for 4 weeks, followed by 30 mg/day for 4 weeks) decreased lidocaine systemic exposure (AUC) by 37% and increased its oral clearance by 56% compared to administration of lidocaine alone. In another study, the mean bioavailability of a single 750 mg oral dose of lidocaine in six patients receiving chronic antiepileptic drug therapy (consisting of one or more of the following enzyme-inducing anticonvulsants: phenobarbital, primidone, phenytoin, carbamazepine) was approximately 2.5-fold lower than that reported for six healthy control subjects, while intrinsic clearance was nearly threefold higher. By contrast, the interaction was modest for lidocaine administered intravenously, suggesting induction of primarily hepatic first-pass rather than systemic metabolism of lidocaine. When a single 100 mg dose of lidocaine was given intravenously, mean lidocaine AUC was reduced by less than 10% and serum clearance increased by just 17% in the epileptic patients compared to controls. These changes were not statistically significant. Likewise, mean lidocaine AUC decreased by approximately 11% and plasma clearance increased by 15% when a single 50 mg intravenous dose of lidocaine was administered following pretreatment with the potent CYP450 inducer rifampin (600 mg/day for six days) in ten healthy, nonsmoking male volunteers. Another pharmacokinetic study found that cigarette smoke, an inducer of CYP450 1A2, reduced the bioavailability of lidocaine when administered orally, but had only minor effects on lidocaine administered intravenously. When 4 smokers and 5 non-smokers received 2 doses of lidocaine (100 mg IV followed by 100 mg orally after a 2-day washout period), the smoker's 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. The clinical impact of smoking on lidocaine has not been studied, however, a loss of efficacy may occur.

References (4)
  1. Heinonen J, Takki S, Jarho L (1970) "Plasma lidocaine levels in patients treated with potential inducers of microsomal enzymes." Acta Anaesthesiol Scand, 14, p. 89-95
  2. Perucca E, Richens A (1979) "Reduction of oral bioavailability of lignocaine by induction of first pass metabolism in epileptic patients." Br J Clin Pharmacol, 8, p. 21-31
  3. Perucca E, Ruprah M, Richens A, Park BK, Betteridge DJ, Hedges AM (1981) "Effect of low-dose phenobarbitone on five indirect indices of hepatic microsomal enzyme induction and plasma lipoproteins in normal subjects." Br J Clin Pharmacol, 12, p. 592-6
  4. Reichel C, Skodra T, Nacke A, Spengler U, Sauerbruch T (1998) "The lignocaine metabolite (MEGX) liver function test and P-450 induction in humans." Br J Clin Pharmacol, 46, p. 535-9

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Drug and food interactions

Moderate

lidocaine food

Applies to: Decadron with Xylocaine (dexamethasone / 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)
  1. 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
  2. (2024) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hospira Inc.
  3. (2015) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hospira Healthcare Corporation
  4. (2022) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hameln Pharma Ltd
  5. (2022) "Product Information. Xylocaine HCl (lidocaine)." Aspen Pharmacare Australia Pty Ltd
  6. 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/
  7. 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/

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Moderate

ritonavir food

Applies to: emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

ADJUST DOSING INTERVAL: Administration with food may modestly affect the bioavailability of ritonavir from the various available formulations. When the oral solution was given under nonfasting conditions, peak ritonavir concentrations decreased 23% and the extent of absorption decreased 7% relative to fasting conditions. Dilution of the oral solution (within one hour of dosing) with 240 mL of chocolate milk or a nutritional supplement (Advera or Ensure) did not significantly affect the extent and rate of ritonavir absorption. When a single 100 mg dose of the tablet was administered with a high-fat meal (907 kcal; 52% fat, 15% protein, 33% carbohydrates), approximately 20% decreases in mean peak concentration (Cmax) and systemic exposure (AUC) were observed relative to administration after fasting. Similar decreases in Cmax and AUC were reported when the tablet was administered with a moderate-fat meal. In contrast, the extent of absorption of ritonavir from the soft gelatin capsule formulation was 13% higher when administered with a meal (615 KCal; 14.5% fat, 9% protein, and 76% carbohydrate) relative to fasting.

MANAGEMENT: Ritonavir should be taken with meals to enhance gastrointestinal tolerability.

References (1)
  1. (2001) "Product Information. Norvir (ritonavir)." Abbott Pharmaceutical

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Moderate

lopinavir food

Applies to: emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

ADJUST DOSING INTERVAL: Food significantly increases the bioavailability of lopinavir from the oral solution formulation of lopinavir-ritonavir. Relative to fasting, administration of lopinavir-ritonavir oral solution with a moderate-fat meal (500 to 682 Kcal; 23% to 25% calories from fat) increased lopinavir peak plasma concentration (Cmax) and systemic exposure (AUC) by 54% and 80%, respectively, whereas administration with a high-fat meal (872 Kcal; 56% from fat) increased lopinavir Cmax and AUC by 56% and 130%, respectively. No clinically significant changes in Cmax and AUC were observed following administration of lopinavir-ritonavir tablets under fed conditions versus fasted conditions. Relative to fasting, administration of a single 400 mg-100 mg dose (two 200 mg-50 mg tablets) with a moderate-fat meal (558 Kcal; 24.1% calories from fat) increased lopinavir Cmax and AUC by 17.6% and 26.9%, respectively, while administration with a high-fat meal (998 Kcal; 51.3% from fat) increased lopinavir AUC by 18.9% but not Cmax. Relative to fasting, ritonavir Cmax and AUC also increased by 4.9% and 14.9%, respectively, with the moderate-fat meal and 10.3% and 23.9%, respectively, with the high-fat meal.

MANAGEMENT: Lopinavir-ritonavir oral solution should be taken with meals to enhance bioavailability and minimize pharmacokinetic variability. Lopinavir-ritonavir tablets may be taken without regard to meals.

References (1)
  1. (2001) "Product Information. Kaletra (lopinavir-ritonavir)." Abbott Pharmaceutical

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Minor

tenofovir food

Applies to: emtricitabine / lopinavir / ritonavir / tenofovir disoproxil

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)
  1. (2001) "Product Information. Viread (tenofovir)." Gilead Sciences

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor 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.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.