From the Guidelines
Medications such as azithromycin and clarithromycin can cause an increase in alkaline phosphatase (ALP) levels, as evidenced by the need for periodic alkaline phosphatase monitoring in patients taking these drugs 1.
Medications Causing ALP Increase
Several medications have been associated with elevated ALP levels, including:
- Azithromycin and clarithromycin, which require periodic ALP monitoring, especially during the first 3 months of therapy 1
- Other antibiotics, such as rifampin and rifabutin, which can cause hepatotoxicity and subsequently elevate ALP levels 1
- Certain anticonvulsants and hormonal medications, although not specifically mentioned in the provided evidence, have been reported to cause ALP elevation in other studies
Mechanism of ALP Elevation
These medications can cause ALP increases through various mechanisms, including:
- Direct hepatotoxicity, leading to liver damage and elevated liver enzymes
- Cholestasis, or impaired bile flow, which can cause ALP elevation
- Induction of enzyme production, resulting in increased ALP levels
Clinical Implications
It is essential to monitor patients taking these medications regularly, especially during the initial treatment period, to detect any potential liver or bone disease. Regular liver function tests, including ALP monitoring, are recommended for patients taking azithromycin and clarithromycin 1. Persistent or significant ALP elevations warrant further investigation to rule out underlying liver or bone disease.
From the FDA Drug Label
Phenytoin may cause increased serum levels of glucose, alkaline phosphatase, and gamma glutamyl transpeptidase (GGT)
- Medications that can cause ALP increase: Phenytoin 2
- Key words: Alkaline phosphatase (ALP) increase, Phenytoin
- Phenytoin can cause an increase in serum alkaline phosphatase levels.
From the Research
Medications that can cause ALP increase
- Antiepileptic drugs, such as phenytoin, carbamazepine, and phenobarbital, have been shown to induce liver microsomal enzymes, which can lead to an increase in serum alkaline phosphatase (ALP) activity 3, 4
- Phenytoin, in particular, has been found to be responsible for the elevation of gamma-glutamyl transpeptidase (gamma-GT) activity, which is often associated with increased ALP activity 4
- Other antiepileptic drugs, such as carbamazepine and valproate, may also contribute to increased ALP activity, although the evidence is less clear 3, 5, 6
- The exact mechanisms by which these medications cause ALP increase are not fully understood, but may involve the induction of liver microsomal enzymes and the inactivation of 1,25-dihydroxycholecalciferol (1,25-DHCC) 3