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Interactions between Fosamprenavir and Tiagabine

1 drug interaction and 12 additional warnings found for the following 2 drugs:

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Drug interactions

Moderate drug interactions

Moderate:

tiaGABine fosamprenavir

Applies to: tiagabine 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as well as clinical and laboratory monitoring may be appropriate for some drugs whenever amprenavir is added to or withdrawn from therapy.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

Food/lifestyle interactions

Moderate food/lifestyle interactions

Moderate:

tiaGABine Food/Lifestyle

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

fosamprenavir Food/Lifestyle

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

Disease interactions

10 potential interactions Applies to: 10 conditions, including High Cholesterol, Depression, Nephrolithiasis, Psychosis, and Diabetes Mellitus.

Abnormal Glucose Tolerance

Moderate:

fosamprenavir

Fosamprenavir has a moderate potential interaction with Abnormal Glucose Tolerance.

New onset diabetes mellitus, exacerbation of preexisting diabetes mellitus, hyperglycemia, and some cases of diabetic ketoacidosis have been reported during postmarketing surveillance in HIV-infected patients treated with protease inhibitors. Some patients required either initiation or dosage adjustments of insulin or oral hypoglycemic agents for treatment of these events. In some cases, hyperglycemia persisted despite discontinuation of protease inhibitor therapy. A causal relationship has not been established between protease inhibitor therapy and these events. Monitoring patients for hyperglycemia, new onset diabetes mellitus, or exacerbation of diabetes mellitus should be considered during protease inhibitor therapy.

Coagulation Defects and Disorders

Moderate:

fosamprenavir

Fosamprenavir has a moderate potential interaction with Coagulation Defects and Disorders.

There have been reports of increased bleeding, including spontaneous skin hematomas and hemarthrosis, in patients with hemophilia type A and B treated with protease inhibitors; however, a causal relationship has not been established. In some patients, additional factor VIII was given. In more than half of the reported cases, protease inhibitor therapy was continued or reintroduced. Patients with hemophilia or other coagulation defects should be monitored closely for bleeding during protease inhibitor therapy.

Dehydration

Moderate:

fosamprenavir

Fosamprenavir has a moderate potential interaction with Dehydration.

Cases of nephrolithiasis have been reported during postmarketing surveillance in HIV-infected patients receiving amprenavir or fosamprenavir therapy. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made. Therapy with amprenavir or fosamprenavir should be administered cautiously in patients with a current or past history of nephrolithiasis. Adequate hydration is recommended. Those who are dehydrated may be at increased risk and should be encouraged to consume additional amounts of liquid or given intravenous fluids if necessary. Patients should be instructed to seek medical attention if they experience potential signs and symptoms of urolithiasis such as flank pain, hematuria, dysuria, and urinary urgency. Temporary interruption or discontinuation of therapy may be required.

Depression

Moderate:

tiagabine

tiaGABine has a moderate potential interaction with Depression.

Antiepileptic drugs (AEDs) have been associated with an increased risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Pooled analyses of 199 placebo-controlled clinical studies involving the use of 11 different AEDs showed that patients receiving AEDs had approximately twice the risk of suicidal thinking or behavior compared to patients receiving placebo. AEDs should be administered cautiously in patients with depression or other psychiatric disorders; phentermine-topiramate should be avoided in patients with history of suicidal attempts or active suicidal ideation. The risk of suicidal thoughts and behavior should be carefully assessed against the risk of untreated illness, bearing in mind that epilepsy and many other conditions for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Patients, caregivers, and families should be alert to the emergence or worsening of signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts or behavior. If patients have symptoms of suicidal ideation or behavior, a dosage reduction or treatment discontinuation should be considered.

Diabetes Mellitus

Moderate:

fosamprenavir

Fosamprenavir has a moderate potential interaction with Diabetes Mellitus.

New onset diabetes mellitus, exacerbation of preexisting diabetes mellitus, hyperglycemia, and some cases of diabetic ketoacidosis have been reported during postmarketing surveillance in HIV-infected patients treated with protease inhibitors. Some patients required either initiation or dosage adjustments of insulin or oral hypoglycemic agents for treatment of these events. In some cases, hyperglycemia persisted despite discontinuation of protease inhibitor therapy. A causal relationship has not been established between protease inhibitor therapy and these events. Monitoring patients for hyperglycemia, new onset diabetes mellitus, or exacerbation of diabetes mellitus should be considered during protease inhibitor therapy.

High Cholesterol

Moderate:

fosamprenavir

Fosamprenavir has a moderate potential interaction with High Cholesterol.

Treatment with ritonavir alone or in combination with other protease inhibitors (e.g., lopinavir, saquinavir, tipranavir, fosamprenavir) has resulted in substantial increases in the concentration of total cholesterol and triglycerides. These effects have also been reported with other protease inhibitors but may be the most dramatic with ritonavir. The clinical significance of these elevations is unclear. Marked elevation in triglyceride levels is a risk factor for development of pancreatitis. Triglyceride and cholesterol testing is recommended before starting ritonavir (with or without other protease inhibitors) and periodically during therapy. Lipid disorders should be managed as clinically appropriate.

History, Nephrolithiasis

Moderate:

fosamprenavir

Fosamprenavir has a moderate potential interaction with History, Nephrolithiasis.

Cases of nephrolithiasis have been reported during postmarketing surveillance in HIV-infected patients receiving amprenavir or fosamprenavir therapy. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made. Therapy with amprenavir or fosamprenavir should be administered cautiously in patients with a current or past history of nephrolithiasis. Adequate hydration is recommended. Those who are dehydrated may be at increased risk and should be encouraged to consume additional amounts of liquid or given intravenous fluids if necessary. Patients should be instructed to seek medical attention if they experience potential signs and symptoms of urolithiasis such as flank pain, hematuria, dysuria, and urinary urgency. Temporary interruption or discontinuation of therapy may be required.

Liver Disease

Major:

tiagabine

tiaGABine has a major potential interaction with Liver Disease.

Tiagabine is extensively metabolized by the liver. In patients with moderately impaired hepatic function (Child-Pugh Class B), the clearance of unbound tiagabine was reduced by about 60%. Therapy with tiagabine should be administered cautiously in patients with liver disease. Reduced dosages and/or longer dosing intervals may be necessary in these patients.

Nephrolithiasis

Moderate:

fosamprenavir

Fosamprenavir has a moderate potential interaction with Nephrolithiasis.

Cases of nephrolithiasis have been reported during postmarketing surveillance in HIV-infected patients receiving amprenavir or fosamprenavir therapy. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made. Therapy with amprenavir or fosamprenavir should be administered cautiously in patients with a current or past history of nephrolithiasis. Adequate hydration is recommended. Those who are dehydrated may be at increased risk and should be encouraged to consume additional amounts of liquid or given intravenous fluids if necessary. Patients should be instructed to seek medical attention if they experience potential signs and symptoms of urolithiasis such as flank pain, hematuria, dysuria, and urinary urgency. Temporary interruption or discontinuation of therapy may be required.

Psychosis

Moderate:

tiagabine

tiaGABine has a moderate potential interaction with Psychosis.

Antiepileptic drugs (AEDs) have been associated with an increased risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Pooled analyses of 199 placebo-controlled clinical studies involving the use of 11 different AEDs showed that patients receiving AEDs had approximately twice the risk of suicidal thinking or behavior compared to patients receiving placebo. AEDs should be administered cautiously in patients with depression or other psychiatric disorders; phentermine-topiramate should be avoided in patients with history of suicidal attempts or active suicidal ideation. The risk of suicidal thoughts and behavior should be carefully assessed against the risk of untreated illness, bearing in mind that epilepsy and many other conditions for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Patients, caregivers, and families should be alert to the emergence or worsening of signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts or behavior. If patients have symptoms of suicidal ideation or behavior, a dosage reduction or treatment discontinuation should be considered.

More resources

fosamprenavir

A total of 546 drugs are known to interact with fosamprenavir.

tiagabine

A total of 381 drugs are known to interact with tiagabine.

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.