From the FDA Drug Label
Phenytoin may cause increased serum levels of glucose, alkaline phosphatase, and gamma glutamyl transpeptidase (GGT)
- Drugs that can elevate GGT levels:
- Phenytoin 1
- Key points:
- Phenytoin may increase GGT levels
- Monitoring of serum phenytoin levels and liver function tests, including GGT, may be necessary during treatment with phenytoin
From the Research
Drugs that can elevate Gamma-Glutamyl Transferase (GGT) levels include statins, such as atorvastatin, as well as other medications like phenytoin, carbamazepine, and certain antibiotics. These medications can cause GGT elevation through liver enzyme induction or by causing mild hepatocellular injury. Some key points to consider include:
- Statins, like atorvastatin, have been associated with GGT elevation, as seen in a case report where a patient's GGT level increased up to 6-fold over the normal level after taking atorvastatin 2.
- Other medications, such as phenytoin, can also increase GGT levels, with one study showing a threefold increase in GGT activity after six months of phenytoin therapy 3.
- The elevation of GGT is often dose-dependent and may occur within days to weeks of starting medication.
- Healthcare providers typically monitor liver function but don't necessarily discontinue the drug unless other liver enzymes are also significantly elevated or symptoms of liver dysfunction appear.
- It's essential to be aware of the potential for GGT elevation when prescribing these medications, especially in patients with pre-existing liver conditions or those taking multiple medications that can affect liver function. Some medications that can increase GGT levels include:
- Statins, such as atorvastatin
- Anticonvulsants, like phenytoin and carbamazepine
- Certain antibiotics, such as cephalosporins
- Oral contraceptives
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- Antifungals, like fluconazole
- Cardiovascular medications, such as warfarin
- Tricyclic antidepressants It's crucial to consider the potential for GGT elevation when prescribing these medications and to monitor liver function accordingly, as elevated GGT levels can be a marker for liver dysfunction or damage 4, 5, 6.