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Interactions between Interferon alfa-n1 and Lipitor

1 drug interaction and 10 additional warnings found for the following 2 drugs:

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Drug interactions

Moderate drug interactions

Moderate:

atorvastatin interferon alfa-n1

Applies to: Lipitor (atorvastatin) and interferon alfa-n1
Monitor

The risk of peripheral neuropathy may be increased during concurrent use of two or more agents that are associated with this adverse effect. Patient risk factors include diabetes and age older than 60 years. In some cases, the neuropathy may progress or become irreversible despite discontinuation of the medications.

Management

Caution is advised during concomitant use of agents with neurotoxic effects. Patients should be monitored closely for symptoms of neuropathy such as burning, tingling, pain, or numbness in the hands and feet. Since the development of peripheral neuropathy may be dose-related for many drugs, the recommended dosages should generally not be exceeded. Consideration should be given to dosage reduction or immediate discontinuation of these medications in patients who develop peripheral neuropathy to limit further damage. If feasible, therapy should generally be reinstituted only after resolution of neuropathy symptoms or return of symptoms to baseline status. In some cases, permanent dosage reductions may be required.

References (4)
  1. Carrion C, Espinosa E, Herrero A, Garcia B (1995) "Possible vincristine-isoniazid interaction." Ann Pharmacother, 29, p. 201
  2. Argov Z, Mastaglia FL (1979) "Drug-induced peripheral neuropathies." Br Med J, 1, p. 663-6
  3. Pharmaceutical Society of Australia (2006) APPGuide online. Australian prescription products guide online. http://www.appco.com.au/appguide/default.asp
  4. 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

Food/lifestyle interactions

Moderate food/lifestyle interactions

Moderate:

atorvastatin Food/Lifestyle

Applies to: Lipitor (atorvastatin)
Generally avoid

Coadministration with grapefruit juice may increase the plasma concentrations of atorvastatin. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. When a single 40 mg dose of atorvastatin was coadministered with 240 mL of grapefruit juice, atorvastatin peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 16% and 37%, respectively. Greater increases in Cmax (up to 71%) and/or AUC (up to 2.5 fold) have been reported with excessive consumption of grapefruit juice (>=750 mL to 1.2 liters per day). Clinically, high levels of HMG-CoA reductase inhibitory activity in plasma is associated with an increased risk of musculoskeletal toxicity. Myopathy manifested as muscle pain and/or weakness associated with grossly elevated creatine kinase exceeding ten times the upper limit of normal has been reported occasionally. Rhabdomyolysis has also occurred rarely, which may be accompanied by acute renal failure secondary to myoglobinuria and may result in death.

Adjust dosing interval

Fibres such as oat bran and pectin may diminish the pharmacologic effects of HMG-CoA reductase inhibitors by interfering with their absorption from the gastrointestinal tract.

Management

Patients receiving therapy with atorvastatin should limit their consumption of grapefruit juice to no more than 1 liter per day. Patients should be advised to promptly report any unexplained muscle pain, tenderness or weakness, particularly if accompanied by fever, malaise and/or dark colored urine. Therapy should be discontinued if creatine kinase is markedly elevated in the absence of strenuous exercise or if myopathy is otherwise suspected or diagnosed. In addition, patients should either refrain from the use of oat bran and pectin or, if concurrent use cannot be avoided, to separate the administration times by at least 2 to 4 hours.

References (7)
  1. Richter WO, Jacob BG, Schwandt P (1991) "Interaction between fibre and lovastatin." Lancet, 338, p. 706
  2. McMillan K (1996) "Considerations in the formulary selection of hydroxymethylglutaryl coenzyme a reductase inhibitors." Am J Health Syst Pharm, 53, p. 2206-14
  3. (2001) "Product Information. Lipitor (atorvastatin)." Parke-Davis
  4. Boberg M, Angerbauer R, Fey P, Kanhai WK, Karl W, Kern A, Ploschke J, Radtke M (1997) "Metabolism of cerivastatin by human liver microsomes in vitro. Characterization of primary metabolic pathways and of cytochrome P45 isozymes involved." Drug Metab Dispos, 25, p. 321-31
  5. Bailey DG, Malcolm J, Arnold O, Spence JD (1998) "Grapefruit juice-drug interactions." Br J Clin Pharmacol, 46, p. 101-10
  6. Lilja JJ, Kivisto KT, Neuvonen PJ (1999) "Grapefruit juice increases serum concentrations of atorvastatin and has no effect on pravastatin." Clin Pharmacol Ther, 66, p. 118-27
  7. Neuvonen PJ, Backman JT, Niemi M (2008) "Pharmacokinetic comparison of the potential over-the-counter statins simvastatin, lovastatin, fluvastatin and pravastatin." Clin Pharmacokinet, 47, p. 463-74

Disease interactions

9 potential interactions Applies to: 8 conditions, including Underactive Thyroid, Diabetes Mellitus, Liver Disease, Alcoholism, and Renal Dysfunction.

Alcoholism

Major:

Lipitor

The atorvastatin in Lipitor has a major potential interaction with Alcoholism.

The use of most HMG-CoA reductase inhibitors is contraindicated in patients with active liver disease, decompensated cirrhosis, or unexplained persistent elevations of serum transaminases. HMG-CoA reductase inhibitors are extensively metabolized by the liver. Decreased drug metabolism may lead to accumulation and increased risk of toxicity, including biochemical abnormalities of liver function and, rarely, jaundice, hepatitis, cirrhosis, fatty change in the liver, and fulminant hepatic necrosis. Therapy with HMG-CoA reductase inhibitors should be administered cautiously in patients with a history of liver disease and/or heavy alcohol use. A lower initial dosage may be appropriate, and clinical monitoring of liver transaminase levels according to the individual manufacturer product information is recommended. Patients who develop elevated ALT or AST levels during therapy should be monitored until abnormalities resolve. If an increase above 3 times the upper limit of normal persists, consideration should be given to a reduction in dosage or withdrawal of therapy.

Central Nervous System Disorders

Moderate:

Lipitor

The atorvastatin in Lipitor has a moderate potential interaction with Central Nervous System Disorders.

Cognitive impairment (e.g., memory loss, forgetfulness, amnesia, memory impairment, confusion) have been observed in patients receiving statins. The reports are usually not serious, and reversible upon statin discontinuation. Caution is recommended when using these agents in patients with cognitive impairment.

Diabetes Mellitus

Moderate:

Lipitor

The atorvastatin in Lipitor has a moderate potential interaction with Diabetes Mellitus.

Increases in hemoglobin A1c and fasting serum glucose levels have been reported with the use of certain HMG-CoA reductase inhibitors. Caution should be exercised when using these agents in diabetic patients and close monitoring is recommended.

Liver Disease

Major:

Lipitor

The atorvastatin in Lipitor has a major potential interaction with Liver Disease.

The use of most HMG-CoA reductase inhibitors is contraindicated in patients with active liver disease, decompensated cirrhosis, or unexplained persistent elevations of serum transaminases. HMG-CoA reductase inhibitors are extensively metabolized by the liver. Decreased drug metabolism may lead to accumulation and increased risk of toxicity, including biochemical abnormalities of liver function and, rarely, jaundice, hepatitis, cirrhosis, fatty change in the liver, and fulminant hepatic necrosis. Therapy with HMG-CoA reductase inhibitors should be administered cautiously in patients with a history of liver disease and/or heavy alcohol use. A lower initial dosage may be appropriate, and clinical monitoring of liver transaminase levels according to the individual manufacturer product information is recommended. Patients who develop elevated ALT or AST levels during therapy should be monitored until abnormalities resolve. If an increase above 3 times the upper limit of normal persists, consideration should be given to a reduction in dosage or withdrawal of therapy.

Myoneural Disorder

Moderate:

Lipitor

The atorvastatin in Lipitor has a moderate potential interaction with Myoneural Disorder.

HMG-CoA reductase inhibitors may cause myopathy and rhabdomyolysis; acute renal failure secondary to myoglobinuria and rare fatalities have occurred due to rhabdomyolysis in patients treated with statins. The myopathy may be dose-related and is characterized by unexplained muscle weakness, pain, or tenderness accompanied by increases in creatine phosphokinase (CPK) values exceeding 10 times the upper limit of normal. Therapy with HMG-CoA reductase inhibitors should be administered cautiously in patients with preexisting myopathy, in those with predisposing factors for myopathy, or with a history of myoneural disorder, since it may delay the recognition or confound the diagnosis of a drug-induced musculoskeletal effect. Patients should be advised to report promptly any unusual muscle pain, tenderness, or weakness, particularly if accompanied by malaise or fever. Periodic CPK determinations may be considered in some patients, although the value of such monitoring is uncertain. HMG-CoA reductase inhibitor therapy should be withdrawn if markedly elevated CPK levels occur or if drug-related myopathy is diagnosed or suspected.

Myopathy

Moderate:

Lipitor

The atorvastatin in Lipitor has a moderate potential interaction with Myopathy.

HMG-CoA reductase inhibitors may cause myopathy and rhabdomyolysis; acute renal failure secondary to myoglobinuria and rare fatalities have occurred due to rhabdomyolysis in patients treated with statins. The myopathy may be dose-related and is characterized by unexplained muscle weakness, pain, or tenderness accompanied by increases in creatine phosphokinase (CPK) values exceeding 10 times the upper limit of normal. Therapy with HMG-CoA reductase inhibitors should be administered cautiously in patients with preexisting myopathy, in those with predisposing factors for myopathy, or with a history of myoneural disorder, since it may delay the recognition or confound the diagnosis of a drug-induced musculoskeletal effect. Patients should be advised to report promptly any unusual muscle pain, tenderness, or weakness, particularly if accompanied by malaise or fever. Periodic CPK determinations may be considered in some patients, although the value of such monitoring is uncertain. HMG-CoA reductase inhibitor therapy should be withdrawn if markedly elevated CPK levels occur or if drug-related myopathy is diagnosed or suspected.

Renal Dysfunction

Moderate:

Lipitor

The atorvastatin in Lipitor has a moderate potential interaction with Renal Dysfunction.

HMG-CoA reductase inhibitors may cause myopathy and rhabdomyolysis; acute renal failure secondary to myoglobinuria and rare fatalities have occurred due to rhabdomyolysis in patients treated with statins. The myopathy may be dose-related and is characterized by unexplained muscle weakness, pain, or tenderness accompanied by increases in creatine phosphokinase (CPK) values exceeding 10 times the upper limit of normal. Therapy with HMG-CoA reductase inhibitors should be administered cautiously in patients with preexisting myopathy, in those with predisposing factors for myopathy, or with a history of myoneural disorder, since it may delay the recognition or confound the diagnosis of a drug-induced musculoskeletal effect. Patients should be advised to report promptly any unusual muscle pain, tenderness, or weakness, particularly if accompanied by malaise or fever. Periodic CPK determinations may be considered in some patients, although the value of such monitoring is uncertain. HMG-CoA reductase inhibitor therapy should be withdrawn if markedly elevated CPK levels occur or if drug-related myopathy is diagnosed or suspected.

Moderate:

Lipitor

The atorvastatin in Lipitor has a moderate potential interaction with Renal Dysfunction.

Some HMG-CoA reductase inhibitors (e.g., fluvastatin) have not been studied in patients with severe renal dysfunction or end-stage renal disease. Some others (e.g., pitavastatin, simvastatin) require a dose reduction when used in this group of patients. Caution and close monitoring are advised when using these drugs in patients with renal dysfunction.

Underactive Thyroid

Moderate:

Lipitor

The atorvastatin in Lipitor has a moderate potential interaction with Underactive Thyroid.

HMG-CoA reductase inhibitors may cause myopathy and rhabdomyolysis; acute renal failure secondary to myoglobinuria and rare fatalities have occurred due to rhabdomyolysis in patients treated with statins. The myopathy may be dose-related and is characterized by unexplained muscle weakness, pain, or tenderness accompanied by increases in creatine phosphokinase (CPK) values exceeding 10 times the upper limit of normal. Therapy with HMG-CoA reductase inhibitors should be administered cautiously in patients with preexisting myopathy, in those with predisposing factors for myopathy, or with a history of myoneural disorder, since it may delay the recognition or confound the diagnosis of a drug-induced musculoskeletal effect. Patients should be advised to report promptly any unusual muscle pain, tenderness, or weakness, particularly if accompanied by malaise or fever. Periodic CPK determinations may be considered in some patients, although the value of such monitoring is uncertain. HMG-CoA reductase inhibitor therapy should be withdrawn if markedly elevated CPK levels occur or if drug-related myopathy is diagnosed or suspected.

More resources

interferon alfa-n1

A total of 226 drugs are known to interact with interferon alfa-n1.

Lipitor

A total of 437 drugs are known to interact with Lipitor.

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.