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Abnormal dexamethasone suppression tests in a rifampicin-treated patient with suspected Cushing's syndrome

Abdullah HN, Nowalid WK

Endokrynol Pol, 2010 Nov-Dec;61(6):706-9.
PMID: 21104646

The dexamethasone suppression test is a useful endocrinological test to diagnose Cushing's syndrome. However, its interpretation may be influenced by many factors such as stress, alcohol, failure to ingest the dexamethasone, altered metabolism, drug interaction and obesity. This report illustrates such an instance, whereby the result of the test was erratic due to the anti-tuberculous drug rifampicin. Rifampicin has been found to profoundly attenuate the biological effects of dexamethasone, probably by enhancing its metabolism in the liver. The exact mechanism of the drug interaction remains elusive, though induction of hepatic CYP3A4 enzyme complex is a possible mechanism. In a patient treated with rifampicin, the results of dexamethasone suppression tests thus have no diagnostic value and can be very misleading.

Matched MeSH terms: Antibiotics, Antitubercular/pharmacology*
Resistant hypertension during antituberculosis treatment: how is rifampicin implicated?

Lee SL, Lim WJ, Chai ST

Med J Malaysia, 2020 09;75(5):591-593.
PMID: 32918434

A 67-year-old mental institute resident was treated for smear-positive pulmonary tuberculosis. His background history included chronic essential hypertension which was well-controlled with amlodipine 10mg daily. However, his blood pressure became suboptimal one week into antitubercular treatment, necessitating escalation of antihypertensive therapy up to six medications. Following completion of antitubercular treatment, his blood pressure improved markedly. The number of antihypertensives was able to be reduced to only two after a month. We postulate that rifampicin has attenuated the therapeutic effect of amlodipine via potent induction of hepatic CYP3A4 but the failure to control the blood pressure even with medications unrelated to cytochrome P450 pathways raises the spectre of an additional interaction.

Matched MeSH terms: Antibiotics, Antitubercular/pharmacology*
Fulltext Influences of proton pump inhibitor on Helicobacter pylori adherence to the gastrointestinal cell lines

Omar MS, Damanhuri NS, Kumolosasi E

Turk J Gastroenterol, 2017 Jan;28(1):53-59.
PMID: 27991853 DOI: 10.5152/tjg.2016.0409

BACKGROUND/AIMS: Helicobacter pylori is a carcinogenic bacterium that could induce P-glycoprotein expression in the human gastrointestinal tract. Bacterial adherence to the gastrointestinal cell lines could be influenced by the level of P-glycoprotein. This study aimed to determine the influence of proton pump inhibitors that exhibit an inhibitory effect on P-glycoprotein in gastrointestinal carcinoma cell lines, namely Caco-2 and LS174T, in relation to H. pylori adherence.
MATERIALS AND METHODS: Caco-2 and LS174T cells lines treated with omeprazole and esomeprazole were used in this study to assess the bacterial attachment of H. pylori within certain incubation periods.
RESULTS: The presence of proton pump inhibitors increased the H. pylori adherence in a time-dependent manner in both Caco-2 and LS174T cell lines. The double inhibition of P-glycoprotein using proton pump inhibitor and P-glycoprotein inhibitor caused low P-glycoprotein expression in the cell lines, resulting in higher H. pylori adherence compared to the control cell lines.
CONCLUSION: Proton pump inhibitors may alter P-glycoprotein expression in the gastrointestinal tract, and subsequently H. pylori adherence on the cell lines, and may contribute to resistance to drug therapy.

Matched MeSH terms: Antibiotics, Antitubercular/pharmacology
Mucoadhesive guargum hydrogel inter-connected chitosan-g-polycaprolactone micelles for rifampicin delivery

Yuan X, Amarnath Praphakar R, Munusamy MA, Alarfaj AA, Suresh Kumar S, Rajan M

Carbohydr Polym, 2019 Feb 15;206:1-10.
PMID: 30553301 DOI: 10.1016/j.carbpol.2018.10.098

Natural polymer guar gum has one of the highest viscosities in water solution and hence, these are significantly used in pharmaceutical applications. Guar gum inter-connected micelles as a new carrier has been developed for poor water soluble rifampicin drug. The hydrogel inter-connected micelle core was formulated as a hydrophilic inner and hydrophobic outer core by using guar gum/chitosan/polycaprolactone and the carrier interaction with rifampicin was confirmed by FT-IR. The morphological observations were carried out through TEM, SEM and AFM analysis. The encapsulation efficiency and in-vitro drug release behavior of prepared hydrogel based micelle system was analyzed by UV-vis spectrometry. The anti-bacterial activity against K. pneumoniae and S. aureus was studied by observing their ruptured surface by SEM. The cytotoxicity study reveals that the pure polymeric system has no toxic effect whereas drug loaded ones showed superior activity against THP-1 cells. From the cell apoptosis analyses, the apoptosis was carried out in a time dependent manner. The cell uptake behavior was also observed in THP-1 cells which indicate that the hydrogel based micelle system is an excellent material for the mucoadhesive on intracellular alveolar macrophage treatment.

Matched MeSH terms: Antibiotics, Antitubercular/pharmacology*