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Drug Interactions between estazolam and fosamprenavir

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

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Interactions between your drugs

Moderate

estazolam fosamprenavir

Applies to: estazolam and fosamprenavir

MONITOR: Coadministration with amprenavir or its prodrug, fosamprenavir, may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4 isoenzyme. The mechanism is decreased clearance due to inhibition of CYP450 3A4 activity by amprenavir.

MANAGEMENT: Caution is advised if amprenavir must be used concurrently with medications that undergo metabolism by CYP450 3A4, particularly those with a narrow therapeutic range. Dosage adjustments as well as clinical and laboratory monitoring may be appropriate for some drugs whenever amprenavir is added to or withdrawn from therapy.

References (3)
  1. (2001) "Product Information. Agenerase (amprenavir)." Glaxo Wellcome
  2. (2003) "Product Information. Lexiva (fosamprenavir)." GlaxoSmithKline
  3. (2021) "Product Information. Qelbree (viloxazine)." Supernus Pharmaceuticals Inc

Drug and food interactions

Moderate

fosamprenavir food

Applies to: fosamprenavir

ADJUST DOSING INTERVAL: Food may reduce the systemic bioavailability of amprenavir from fosamprenavir oral suspension. The mechanism of interaction has not been described. According to the product labeling, administration of fosamprenavir oral suspension (1400 mg single dose) with a high-fat meal (967 kcal, 67 g fat, 33 g protein, 58 g carbohydrate) reduced amprenavir peak plasma concentration (Cmax) by 46% and systemic exposure (AUC) by 28% compared to administration in a fasted state. The time to reach peak plasma level (Tmax) was delayed by 0.72 hours. In contrast, the same high-fat meal did not affect the pharmacokinetics of amprenavir from fosamprenavir tablets.

MANAGEMENT: Fosamprenavir suspension should be administered on an empty stomach in adults, but with food in pediatric patients to aid palatability and compliance. If emesis occurs within 30 minutes after dosing the suspension, the dose should be repeated. Fosamprenavir tablets may be taken with or without food.

References (1)
  1. (2003) "Product Information. Lexiva (fosamprenavir)." GlaxoSmithKline
Moderate

estazolam food

Applies to: estazolam

GENERALLY AVOID: Acute ethanol ingestion may potentiate the CNS effects of many benzodiazepines. Tolerance may develop with chronic ethanol use. The mechanism may be decreased clearance of the benzodiazepines because of CYP450 hepatic enzyme inhibition. Also, it has been suggested that the cognitive deficits induced by benzodiazepines may be increased in patients who chronically consume large amounts of alcohol.

MANAGEMENT: Patients should be advised to avoid alcohol during benzodiazepine therapy.

References (7)
  1. MacLeod SM, Giles HG, Patzalek G, Thiessen JJ, Sellers EM (1977) "Diazepam actions and plasma concentrations following ethanol ingestion." Eur J Clin Pharmacol, 11, p. 345-9
  2. Whiting B, Lawrence JR, Skellern GG, Meier J (1979) "Effect of acute alcohol intoxication on the metabolism and plasma kinetics of chlordiazepoxide." Br J Clin Pharmacol, 7, p. 95-100
  3. Divoll M, Greenblatt DJ, Lacasse Y, Shader RI (1981) "Benzodiazepine overdosage: plasma concentrations and clinical outcome." Psychopharmacology (Berl), 73, p. 381-3
  4. Juhl RP, Van Thiel DH, Dittert LW, Smith RB (1984) "Alprazolam pharmacokinetics in alcoholic liver disease." J Clin Pharmacol, 24, p. 113-9
  5. Ochs HR, Greenblatt DJ, Arendt RM, Hubbel W, Shader RI (1984) "Pharmacokinetic noninteraction of triazolam and ethanol." J Clin Psychopharmacol, 4, p. 106-7
  6. Staak M, Raff G, Nusser W (1979) "Pharmacopsychological investigations concerning the combined effects of dipotassium clorazepate and ethanol." Int J Clin Pharmacol Biopharm, 17, p. 205-12
  7. Nichols JM, Martin F, Kirkby KC (1993) "A comparison of the effect of lorazepam on memory in heavy and low social drinkers." Psychopharmacology (Berl), 112, p. 475-82

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.

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