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Drug Interactions between cobicistat / darunavir / emtricitabine / tenofovir alafenamide and dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine

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

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Interactions between your drugs

Moderate

dextromethorphan pyrilamine

Applies to: dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine and dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. Sedation and impairment of attention, judgment, thinking, and psychomotor skills may increase.

MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Cautious dosage titration may be required, particularly at treatment initiation. Ambulatory patients should be counseled to avoid hazardous activities requiring mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Hamilton MJ, Bush M, Smith P, Peck AW "The effects of bupropion, a new antidepressant drug, and diazepam, and their interaction in man." Br J Clin Pharmacol 14 (1982): 791-7
  2. Stambaugh JE, Lane C "Analgesic efficacy and pharmacokinetic evaluation of meperidine and hydroxyzine, alone and in combination." Cancer Invest 1 (1983): 111-7
  3. Sotaniemi EA, Anttila M, Rautio A, et al. "Propranolol and sotalol metabolism after a drinking party." Clin Pharmacol Ther 29 (1981): 705-10
  4. Grabowski BS, Cady WJ, Young WW, Emery JF "Effects of acute alcohol administration on propranolol absorption." Int J Clin Pharmacol Ther Toxicol 18 (1980): 317-9
  5. Lemberger L, Rowe H, Bosomworth JC, Tenbarge JB, Bergstrom RF "The effect of fluoxetine on the pharmacokinetics and psychomotor responses of diazepam." Clin Pharmacol Ther 43 (1988): 412-9
  6. MacLeod SM, Giles HG, Patzalek G, Thiessen JJ, Sellers EM "Diazepam actions and plasma concentrations following ethanol ingestion." Eur J Clin Pharmacol 11 (1977): 345-9
  7. Divoll M, Greenblatt DJ, Lacasse Y, Shader RI "Benzodiazepine overdosage: plasma concentrations and clinical outcome." Psychopharmacology (Berl) 73 (1981): 381-3
  8. Naylor GJ, McHarg A "Profound hypothermia on combined lithium carbonate and diazepam treatment." Br Med J 2 (1977): 22
  9. Stovner J, Endresen R "Intravenous anaesthesia with diazepam." Acta Anaesthesiol Scand 24 (1965): 223-7
  10. Driessen JJ, Vree TB, Booij LH, van der Pol FM, Crul JF "Effect of some benzodiazepines on peripheral neuromuscular function in the rat in-vitro hemidiaphragm preparation." J Pharm Pharmacol 36 (1984): 244-7
  11. Feldman SA, Crawley BE "Interaction of diazepam with the muscle-relaxant drugs." Br Med J 1 (1970): 336-8
  12. Ochs HR, Greenblatt DJ, Verburg-Ochs B "Propranolol interactions with diazepam, lorazepam and alprazolam." Clin Pharmacol Ther 36 (1984): 451-5
  13. Desager JP, Hulhoven R, Harvengt C, Hermann P, Guillet P, Thiercelin JF "Possible interactions between zolpidem, a new sleep inducer and chlorpromazine, a phenothiazine neuroleptic." Psychopharmacology (Berl) 96 (1988): 63-6
  14. Tverskoy M, Fleyshman G, Ezry J, Bradley EL, Jr Kissin I "Midazolam-morphine sedative interaction in patients." Anesth Analg 68 (1989): 282-5
  15. "Product Information. Iopidine (apraclonidine ophthalmic)." Alcon Laboratories Inc PROD
  16. Greiff JMC, Rowbotham D "Pharmacokinetic drug interactions with gastrointestinal motility modifying agents." Clin Pharmacokinet 27 (1994): 447-61
  17. Greb WH, Buscher G, Dierdorf HD, Koster FE, Wolf D, Mellows G "The effect of liver enzyme inhibition by cimetidine and enzyme induction by phenobarbitone on the pharmacokinetics of paroxetine." Acta Psychiatr Scand 80 Suppl (1989): 95-8
  18. Markowitz JS, Wells BG, Carson WH "Interactions between antipsychotic and antihypertensive drugs." Ann Pharmacother 29 (1995): 603-9
  19. "Product Information. Ultram (tramadol)." McNeil Pharmaceutical PROD (2001):
  20. "Product Information. Artane (trihexyphenidyl)." Lederle Laboratories PROD (2001):
  21. "Product Information. Ultiva (remifentanil)." Mylan Institutional (formally Bioniche Pharma USA Inc) PROD (2001):
  22. "Product Information. Seroquel (quetiapine)." Astra-Zeneca Pharmaceuticals PROD (2001):
  23. "Product Information. Meridia (sibutramine)." Knoll Pharmaceutical Company PROD (2001):
  24. "Product Information. Tasmar (tolcapone)." Valeant Pharmaceuticals PROD (2001):
  25. Miller LG "Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions." Arch Intern Med 158 (1998): 2200-11
  26. "Product Information. Precedex (dexmedetomidine)." Abbott Pharmaceutical PROD (2001):
  27. "Product Information. Trileptal (oxcarbazepine)." Novartis Pharmaceuticals PROD (2001):
  28. Ferslew KE, Hagardorn AN, McCormick WF "A fatal interaction of methocarbamol and ethanol in an accidental poisoning." J Forensic Sci 35 (1990): 477-82
  29. Plushner SL "Valerian: valeriana officinalis." Am J Health Syst Pharm 57 (2000): 328-35
  30. "Product Information. Xatral (alfuzosin)." Sanofi-Synthelabo Canada Inc (2002):
  31. "Product Information. Lexapro (escitalopram)." Forest Pharmaceuticals (2002):
  32. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  33. Cerner Multum, Inc. "Australian Product Information." O 0
  34. "Product Information. Fycompa (perampanel)." Eisai Inc (2012):
  35. "Product Information. Belsomra (suvorexant)." Merck & Co., Inc (2014):
  36. "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc (2015):
View all 36 references

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Moderate

dextromethorphan dexchlorpheniramine

Applies to: dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine and dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. Sedation and impairment of attention, judgment, thinking, and psychomotor skills may increase.

MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Cautious dosage titration may be required, particularly at treatment initiation. Ambulatory patients should be counseled to avoid hazardous activities requiring mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Hamilton MJ, Bush M, Smith P, Peck AW "The effects of bupropion, a new antidepressant drug, and diazepam, and their interaction in man." Br J Clin Pharmacol 14 (1982): 791-7
  2. Stambaugh JE, Lane C "Analgesic efficacy and pharmacokinetic evaluation of meperidine and hydroxyzine, alone and in combination." Cancer Invest 1 (1983): 111-7
  3. Sotaniemi EA, Anttila M, Rautio A, et al. "Propranolol and sotalol metabolism after a drinking party." Clin Pharmacol Ther 29 (1981): 705-10
  4. Grabowski BS, Cady WJ, Young WW, Emery JF "Effects of acute alcohol administration on propranolol absorption." Int J Clin Pharmacol Ther Toxicol 18 (1980): 317-9
  5. Lemberger L, Rowe H, Bosomworth JC, Tenbarge JB, Bergstrom RF "The effect of fluoxetine on the pharmacokinetics and psychomotor responses of diazepam." Clin Pharmacol Ther 43 (1988): 412-9
  6. MacLeod SM, Giles HG, Patzalek G, Thiessen JJ, Sellers EM "Diazepam actions and plasma concentrations following ethanol ingestion." Eur J Clin Pharmacol 11 (1977): 345-9
  7. Divoll M, Greenblatt DJ, Lacasse Y, Shader RI "Benzodiazepine overdosage: plasma concentrations and clinical outcome." Psychopharmacology (Berl) 73 (1981): 381-3
  8. Naylor GJ, McHarg A "Profound hypothermia on combined lithium carbonate and diazepam treatment." Br Med J 2 (1977): 22
  9. Stovner J, Endresen R "Intravenous anaesthesia with diazepam." Acta Anaesthesiol Scand 24 (1965): 223-7
  10. Driessen JJ, Vree TB, Booij LH, van der Pol FM, Crul JF "Effect of some benzodiazepines on peripheral neuromuscular function in the rat in-vitro hemidiaphragm preparation." J Pharm Pharmacol 36 (1984): 244-7
  11. Feldman SA, Crawley BE "Interaction of diazepam with the muscle-relaxant drugs." Br Med J 1 (1970): 336-8
  12. Ochs HR, Greenblatt DJ, Verburg-Ochs B "Propranolol interactions with diazepam, lorazepam and alprazolam." Clin Pharmacol Ther 36 (1984): 451-5
  13. Desager JP, Hulhoven R, Harvengt C, Hermann P, Guillet P, Thiercelin JF "Possible interactions between zolpidem, a new sleep inducer and chlorpromazine, a phenothiazine neuroleptic." Psychopharmacology (Berl) 96 (1988): 63-6
  14. Tverskoy M, Fleyshman G, Ezry J, Bradley EL, Jr Kissin I "Midazolam-morphine sedative interaction in patients." Anesth Analg 68 (1989): 282-5
  15. "Product Information. Iopidine (apraclonidine ophthalmic)." Alcon Laboratories Inc PROD
  16. Greiff JMC, Rowbotham D "Pharmacokinetic drug interactions with gastrointestinal motility modifying agents." Clin Pharmacokinet 27 (1994): 447-61
  17. Greb WH, Buscher G, Dierdorf HD, Koster FE, Wolf D, Mellows G "The effect of liver enzyme inhibition by cimetidine and enzyme induction by phenobarbitone on the pharmacokinetics of paroxetine." Acta Psychiatr Scand 80 Suppl (1989): 95-8
  18. Markowitz JS, Wells BG, Carson WH "Interactions between antipsychotic and antihypertensive drugs." Ann Pharmacother 29 (1995): 603-9
  19. "Product Information. Ultram (tramadol)." McNeil Pharmaceutical PROD (2001):
  20. "Product Information. Artane (trihexyphenidyl)." Lederle Laboratories PROD (2001):
  21. "Product Information. Ultiva (remifentanil)." Mylan Institutional (formally Bioniche Pharma USA Inc) PROD (2001):
  22. "Product Information. Seroquel (quetiapine)." Astra-Zeneca Pharmaceuticals PROD (2001):
  23. "Product Information. Meridia (sibutramine)." Knoll Pharmaceutical Company PROD (2001):
  24. "Product Information. Tasmar (tolcapone)." Valeant Pharmaceuticals PROD (2001):
  25. Miller LG "Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions." Arch Intern Med 158 (1998): 2200-11
  26. "Product Information. Precedex (dexmedetomidine)." Abbott Pharmaceutical PROD (2001):
  27. "Product Information. Trileptal (oxcarbazepine)." Novartis Pharmaceuticals PROD (2001):
  28. Ferslew KE, Hagardorn AN, McCormick WF "A fatal interaction of methocarbamol and ethanol in an accidental poisoning." J Forensic Sci 35 (1990): 477-82
  29. Plushner SL "Valerian: valeriana officinalis." Am J Health Syst Pharm 57 (2000): 328-35
  30. "Product Information. Xatral (alfuzosin)." Sanofi-Synthelabo Canada Inc (2002):
  31. "Product Information. Lexapro (escitalopram)." Forest Pharmaceuticals (2002):
  32. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  33. Cerner Multum, Inc. "Australian Product Information." O 0
  34. "Product Information. Fycompa (perampanel)." Eisai Inc (2012):
  35. "Product Information. Belsomra (suvorexant)." Merck & Co., Inc (2014):
  36. "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc (2015):
View all 36 references

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Moderate

pyrilamine dexchlorpheniramine

Applies to: dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine and dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine

MONITOR: Agents with anticholinergic properties (e.g., sedating antihistamines; antispasmodics; neuroleptics; phenothiazines; skeletal muscle relaxants; tricyclic antidepressants; disopyramide) may have additive effects when used in combination. Excessive parasympatholytic effects may result in paralytic ileus, hyperthermia, heat stroke, and the anticholinergic intoxication syndrome. Peripheral symptoms of intoxication commonly include mydriasis, blurred vision, flushed face, fever, dry skin and mucous membranes, tachycardia, urinary retention, and constipation. Central symptoms may include memory loss, disorientation, incoherence, hallucinations, psychosis, delirium, hyperactivity, twitching or jerking movements, stereotypy, and seizures. Central nervous system-depressant effects may also be additively or synergistically increased when these agents are combined, especially in elderly or debilitated patients. Use of neuroleptics in combination with other neuroleptics or anticholinergic agents may increase the risk of tardive dyskinesia. In addition, some neuroleptics and tricyclic antidepressants may cause prolongation of the QT interval and theoretically, concurrent use of two or more drugs that can cause QT interval prolongation may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death.

MANAGEMENT: Caution is advised when agents with anticholinergic properties are combined, particularly in the elderly and those with underlying organic brain disease, who tend to be more sensitive to the central anticholinergic effects of these drugs and in whom toxicity symptoms may be easily overlooked. Patients should be advised to notify their physician promptly if they experience potential symptoms of anticholinergic intoxication such as abdominal pain, fever, heat intolerance, blurred vision, confusion, and/or hallucinations. Ambulatory patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them. A reduction in anticholinergic dosages may be necessary if excessive adverse effects develop.

References

  1. Stadnyk AN, Glezos JD "Drug-induced heat stroke." Can Med Assoc J 128 (1983): 957-9
  2. Zelman S, Guillan R "Heat stroke in phenothiazine-treated patients: a report of three fatalities." Am J Psychiatry 126 (1970): 1787-90
  3. Mann SC, Boger WP "Psychotropic drugs, summer heat and humidity, and hyperplexia: a danger restated." Am J Psychiatry 135 (1978): 1097-100
  4. Warnes H, Lehmann HE, Ban TA "Adynamic ileus during psychoactive medication: a report of three fatal and five severe cases." Can Med Assoc J 96 (1967): 1112-3
  5. Gershon S, Neubauer H, Sundland DM "Interaction between some anticholinergic agents and phenothiazines." Clin Pharmacol Ther 6 (1965): 749-56
  6. Sarnquist F, Larson CP Jr "Drug-induced heat stroke." Anesthesiology 39 (1973): 348-50
  7. Johnson AL, Hollister LE, Berger PA "The anticholinergic intoxication syndrome: diagnosis and treatment." J Clin Psychiatry 42 (1981): 313-7
  8. Lee BS "Possibility of hyperpyrexia with antipsychotic and anticholinergic drugs." J Clin Psychiatry 47 (1986): 571
  9. Forester D "Fatal drug-induced heat stroke." JACEP 7 (1978): 243-4
  10. Moreau A, Jones BD, Banno V "Chronic central anticholinergic toxicity in manic depressive illness mimicking dementia." Can J Psychiatry 31 (1986): 339-41
  11. Hvizdos AJ, Bennett JA, Wells BG, Rappaport KB, Mendel SA "Anticholinergic psychosis in a patient receiving usual doses of haloperidol." Clin Pharm 2 (1983): 174-8
  12. Cohen MA, Alfonso CA, Mosquera M "Development of urinary retention during treatment with clozapine and meclizine [published erratum appears in Am J Psychiatry 1994 Jun;151(6):952]." Am J Psychiatry 151 (1994): 619-20
  13. "Product Information. Cogentin (benztropine)." Merck & Co., Inc PROD (2001):
  14. Kulik AV, Wilbur R "Delirium and stereotypy from anticholinergic antiparkinson drugs." Prog Neuropsychopharmacol Biol Psychiatry 6 (1982): 75-82
  15. "Product Information. Artane (trihexyphenidyl)." Lederle Laboratories PROD (2001):
View all 15 references

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Moderate

tenofovir darunavir

Applies to: cobicistat / darunavir / emtricitabine / tenofovir alafenamide and cobicistat / darunavir / emtricitabine / tenofovir alafenamide

MONITOR: Coadministration of tenofovir and darunavir-ritonavir or darunavir-cobicistat may result in increased plasma concentrations of tenofovir and darunavir. Increased tenofovir plasma concentration 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 is unknown; however, increased tenofovir concentrations may be related to inhibition of P-glycoprotein by darunavir, cobicistat, or ritonavir in the renal tubules. Cobicistat may decrease estimated creatinine clearance via inhibition of tubular secretion of creatinine; however, renal glomerular function does not appear to be affected. In 12 study subjects, administration of darunavir-ritonavir (300 mg-100 mg twice daily) with tenofovir (300 mg once daily) increased the systemic exposure (AUC) and trough plasma concentration (Cmin) of darunavir by 21% and 24%, respectively, compared to administration without tenofovir. Tenofovir AUC and Cmin also increased by 22% and 37%, respectively, in the presence of darunavir-ritonavir. 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: Caution and close monitoring of renal function is recommended if darunavir-ritonavir or darunavir-cobicistat is to be used in combination with tenofovir, particularly in patients with risk factors for renal impairment. No dose adjustments appear necessary during coadministration of darunavir-ritonavir with tenofovir. However, 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.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  2. "Product Information. Prezista (darunavir)." Ortho Biotech Inc (2006):
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. "Product Information. Prezcobix (cobicistat-darunavir)." Janssen Pharmaceuticals (2014):
View all 4 references

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Moderate

dextromethorphan cobicistat

Applies to: dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine and cobicistat / darunavir / emtricitabine / tenofovir alafenamide

MONITOR: Coadministration with CYP450 2D6 inhibitors may increase the plasma concentrations of dextromethorphan in patients who are extensive metabolizers of this isoenzyme (approximately 93% of Caucasians and more than 98% of Asians and individuals of African descent). The proposed mechanism is inhibition of the CYP450 2D6-mediated O-demethylation of dextromethorphan. Increased plasma concentrations increase the risk of dextromethorphan-related adverse effects (e.g., agitation, confusion, tremor, insomnia, diarrhea, and respiratory depression) and serotonin syndrome. Coadministration of dextromethorphan (60 mg orally, once) with the CYP450 2D6 inhibitor panobinostat (20 mg orally once a day on days 3, 5, and 8) in 14 patients with advanced cancer had a highly variable effect on dextromethorphan levels, increasing the peak plasma concentration (Cmax) of dextromethorphan by 20% to 200%, and total systemic exposure (AUC 0 to infinity) by 20% to 130%, compared to dextromethorphan given alone. In addition, multiple doses of the potent CYP450 2D6 inhibitor cinacalcet (50 mg daily), increased the AUC of a single 30 mg dextromethorphan dose by 11-fold in extensive metabolizers of this isoenzyme. The moderate CYP450 2D6 inhibitor asunaprevir, given at 200 mg twice daily, also increased Cmax and AUC of a single 30 mg dose of dextromethorphan by 2.7- and 3.9-fold, respectively, in 17 study subjects.

MANAGEMENT: Caution should be exercised if these drugs must be used together. Patients should be monitored for signs of dextromethorphan adverse effects (e.g., agitation, confusion, tremor, insomnia, diarrhea, and respiratory depression) and serotonin syndrome, and advised to notify their health care professional if these adverse effects develop or worsen. Dose reduction of dextromethorphan may also be required.

References

  1. Funck-Brentano C, Jacqz-Aigrain E, Leenhardt A, Roux A, Poirier JM, Jaillon P "Influence of amiodarone on genetically determined drug metabolism in humans." Clin Pharmacol Ther 50 (1991): 259-66
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. "Product Information. Zytiga (abiraterone)." Centocor Inc (2011):
  5. "Product Information. Farydak (panobinostat)." Novartis Pharmaceuticals (2015):
  6. "Product Information. Qelbree (viloxazine)." Supernus Pharmaceuticals Inc (2021):
View all 6 references

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Moderate

tenofovir cobicistat

Applies to: cobicistat / darunavir / emtricitabine / tenofovir alafenamide and cobicistat / darunavir / 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

  1. "Product Information. Viread (tenofovir)." Gilead Sciences (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. "Product Information. Tybost (cobicistat)." Gilead Sciences (2014):
View all 4 references

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Moderate

emtricitabine cobicistat

Applies to: cobicistat / darunavir / emtricitabine / tenofovir alafenamide and cobicistat / darunavir / 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

  1. "Product Information. Viramune (nevirapine)." Boehringer-Ingelheim PROD (2001):
  2. "Product Information. Sustiva (efavirenz)." DuPont Pharmaceuticals PROD (2001):
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  4. "Product Information. Prezista (darunavir)." Ortho Biotech Inc (2006):
  5. "Product Information. Intelence (etravirine)." Ortho Biotech Inc (2008):
  6. Cerner Multum, Inc. "Australian Product Information." O 0
  7. "Product Information. Stribild (cobicistat/elvitegravir/emtricitabine/tenofov)." Gilead Sciences (2012):
  8. "Product Information. Tybost (cobicistat)." Gilead Sciences (2014):
  9. "Product Information. Prezcobix (cobicistat-darunavir)." Janssen Pharmaceuticals (2014):
  10. "Product Information. Evotaz (atazanavir-cobicistat)." Bristol-Myers Squibb (2015):
View all 10 references

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Drug and food interactions

Moderate

dextromethorphan food

Applies to: dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Warrington SJ, Ankier SI, Turner P "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology 15 (1986): 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc. (1990):
  3. "Product Information. Fycompa (perampanel)." Eisai Inc (2012):
  4. "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc (2015):
View all 4 references

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Moderate

pyrilamine food

Applies to: dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Warrington SJ, Ankier SI, Turner P "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology 15 (1986): 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc. (1990):
  3. "Product Information. Fycompa (perampanel)." Eisai Inc (2012):
  4. "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc (2015):
View all 4 references

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Moderate

dexchlorpheniramine food

Applies to: dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Warrington SJ, Ankier SI, Turner P "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology 15 (1986): 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc. (1990):
  3. "Product Information. Fycompa (perampanel)." Eisai Inc (2012):
  4. "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc (2015):
View all 4 references

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Moderate

darunavir food

Applies to: cobicistat / darunavir / emtricitabine / tenofovir alafenamide

ADJUST DOSING INTERVAL: Food enhances the absorption and oral bioavailability of darunavir administered in combination with low-dose ritonavir. The mechanism is unknown. When administered with food, the peak plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) of darunavir were approximately 30% higher than when administered in the fasting state. Darunavir exposure was similar for the range of meals studied. The total caloric content of the various meals evaluated ranged from 240 Kcal (12 grams fat) to 928 Kcal (56 grams fat).

MANAGEMENT: To ensure maximal oral absorption, darunavir coadministered with ritonavir should be taken with food. The type of food is not important.

References

  1. "Product Information. Prezista (darunavir)." Ortho Biotech Inc (2006):

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Moderate

phenylephrine food

Applies to: dexchlorpheniramine / dextromethorphan / phenylephrine / pyrilamine

MONITOR: Coadministration of two or more sympathomimetic agents may increase the risk of adverse effects such as nervousness, irritability, and increased heart rate. Central nervous system (CNS) stimulants, particularly amphetamines, can potentiate the adrenergic response to vasopressors and other sympathomimetic agents. Additive increases in blood pressure and heart rate may occur due to enhanced peripheral sympathetic activity.

MANAGEMENT: Caution is advised if two or more sympathomimetic agents are coadministered. Pulse and blood pressure should be closely monitored.

References

  1. Rosenblatt JE, Lake CR, van Kammen DP, Ziegler MG, Bunney WE Jr "Interactions of amphetamine, pimozide, and lithium on plasma norepineophrine and dopamine-beta-hydroxylase in schizophrenic patients." Psychiatry Res 1 (1979): 45-52
  2. Cavanaugh JH, Griffith JD, Oates JA "Effect of amphetamine on the pressor response to tyramine: formation of p-hydroxynorephedrine from amphetamine in man." Clin Pharmacol Ther 11 (1970): 656
  3. "Product Information. Adderall (amphetamine-dextroamphetamine)." Shire Richwood Pharmaceutical Company Inc PROD (2001):
  4. "Product Information. Tenuate (diethylpropion)." Aventis Pharmaceuticals PROD (2001):
  5. "Product Information. Sanorex (mazindol)." Novartis Pharmaceuticals PROD (2001):
  6. "Product Information. Focalin (dexmethylphenidate)." Mikart Inc (2001):
  7. "Product Information. Strattera (atomoxetine)." Lilly, Eli and Company (2002):
View all 7 references

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Minor

tenofovir food

Applies to: cobicistat / darunavir / 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. "Product Information. Viread (tenofovir)." Gilead Sciences (2001):

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Therapeutic duplication warnings

No 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.


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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.