Rifampicin and anti-hypertensive drugs in chronic kidney disease: Pharmacokinetic interactions and their clinical impact

Potential drug-drug interactions of frequently prescribed medications in long COVID detected by two electronic databases

Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to a wide range of acute and chronic complications including long COVID, a well-known chronic sequela. Long COVID often necessitates long-term treatment, which may lead to an increased potential for drug-drug interactions (DDIs). The objective of this study was to assess potential DDIs among frequently prescribed medications in long COVID by using two electronic databases. Sixty frequently prescribed agents were selected from Thailand's National List of Essential Medicine 2022 for potential DDI analysis by Micromedex and Drugs.com. From these databases, 488 potential DDIs were identified. There were 271 and 434 DDI pairs based on Micromedex and Drugs.com, respectively. Among these DDIs, 77 pairs were labeled as contraindicated or major by both databases. The most common mechanisms for these serious interactions are cytochrome P450 (CYP) inhibition (45%), CYP induction (19%), and QT interval prolongation (7.8%). Based on Fleiss' kappa (0.073), there was only slight agreement of the DDI severity classifications between these two databases. In conclusion, a large number of potential DDIs were detected among frequently prescribed medications for long COVID. Health care providers should be aware of these DDIs, particularly those that are deemed as contraindicated or major. These DDIs are most likely to cause significant adverse events in patients with long COVID because polypharmacy is common.

Assessing the Effect of the Anti-tuberculosis Drug Rifampicin on Known Hypertensive Patients With Tuberculosis in a Tertiary Care Center

Background Epidemiological evidence suggests an indirect link between hypertension and tuberculosis, and several studies have reported that rifampicin has potentially diminished the hypotensive effects of many anti-hypertensive agents by inducing cytochrome P450. This study investigates rifampicin's effect on the target blood pressure in known hypertensive patients whose blood pressure had been previously controlled with anti-hypertensive drugs. Methodology This prospective observational study was conducted at the Institute of Internal Medicine, Madras Medical College and Rajiv Gandhi Government General Hospital, Chennai, from June 2021 to December 2022. A total of 160 patients with known hypertension on anti-hypertensive drugs were recruited for this study. All these patients had been recently diagnosed with tuberculosis and had been treated with rifampicin-based anti-tuberculosis therapy (ATT). Results The maximum number of patients were under 50 years of age and predominantly male (67%). A total of 91 (57%) patients were hypertensive for less than five years, and the remaining patients were hypertensive within 6-10 years or more than 10 years. However, these patients had other comorbidities such as diabetes mellitus (32%) and coronary artery disease (27%). Before ATT, the mean systolic blood pressure (SBP)/diastolic blood pressure (DBP) was recorded to be 130/80 mmHg. The last six months' course of ATT showed mean values around 154/96 mmHg even after adding additional/multiple anti-hypertensive drugs. After discontinuation of ATT, the mean SBP/DBP was effectively 130/80 mmHg at four weeks. Conclusions Rifampicin significantly diminishes the hypotensive effects of many well-established anti-hypertensives such as calcium channel blockers, beta-blockers, and diuretics to maintain blood pressure.

Rifampicin-induced hypertensive urgency: eyes see what the mind knows

A man had poor control of hypertension throughout 9 months of antituberculosis treatment. He consulted multiple physicians, who kept increasing this blood pressure medicine. Despite that, it was not controlled and he visited emergency many times with hypertensive urgency. When admitted in our care, he was off antituberculosis treatment for 5 days and his blood pressure was back to normal. We attributed it secondary to rifamipicin-induced enzyme induction. Tuberculosis and hypertension both being very common diseases, we report this case to highlight lack of awareness about these important and easily preventable drug interactions.

ISPD peritonitis guideline recommendations: 2022 update on prevention and treatment

Peritoneal dialysis (PD)-associated peritonitis is a serious complication of PD and prevention and treatment of such is important in reducing patient morbidity and mortality. The ISPD 2022 updated recommendations have revised and clarified definitions for refractory peritonitis, relapsing peritonitis, peritonitis-associated catheter removal, PD-associated haemodialysis transfer, peritonitis-associated death and peritonitis-associated hospitalisation. New peritonitis categories and outcomes including pre-PD peritonitis, enteric peritonitis, catheter-related peritonitis and medical cure are defined. The new targets recommended for overall peritonitis rate should be no more than 0.40 episodes per year at risk and the percentage of patients free of peritonitis per unit time should be targeted at >80% per year. Revised recommendations regarding management of contamination of PD systems, antibiotic prophylaxis for invasive procedures and PD training and reassessment are included. New recommendations regarding management of modifiable peritonitis risk factors like domestic pets, hypokalaemia and histamine-2 receptor antagonists are highlighted. Updated recommendations regarding empirical antibiotic selection and dosage of antibiotics and also treatment of peritonitis due to specific microorganisms are made with new recommendation regarding adjunctive oral N-acetylcysteine therapy for mitigating aminoglycoside ototoxicity. Areas for future research in prevention and treatment of PD-related peritonitis are suggested.

Predicting Interactions between Rifampin and Antihypertensive Drugs Using the Biopharmaceutics Drug Disposition Classification System

STUDY OBJECTIVE

Lack of blood pressure control is often seen in hypertensive patients concomitantly taking antituberculosis medications due to the complex drug-drug interactions between rifampin and antihypertensive drugs. Therefore, it is of clinical importance to understand the underlying mechanisms of these interactions to help formulate recommendations on the use of antihypertensive drugs in patients taking these medications concomitantly. Our objective was to assess the reliability of the Biopharmaceutics Drug Disposition Classification System (BDDCS) to predict potential interactions between rifampin and antihypertensive drugs and thus provide recommendations on the choice of antihypertensive drugs in patients receiving rifampin.

DESIGN

Evidence-based in vitro and in vivo predictions of drug-drug interactions.

MEASUREMENTS AND MAIN RESULTS

We systematically evaluated interactions between rifampin and antihypertensive drugs using the theory of the BDDCS, taking into consideration the role of drug transporters and metabolic enzymes involved in these interactions. We provide recommendations on the selection of antihypertensive drugs for patients with tuberculosis. Antihypertensive drugs approved by the U.S. Food and Drug Administration and the China National Medical Products Administration were included in this study. The drugs were classified into four categories under the BDDCS classification. Detailed information on cytochrome P450 (CYP) enzymes and drug transporters for each antihypertensive drug was searched in PubMed and other electronic databases. This information was combined with the effects of rifampin on CYP enzymes and drug transporters, and the direction and relative extent of the potential interactions between rifampin and antihypertensive drugs were predicted. Recommendations were then made using the theory of BDDCS. A thorough systematic literature review was performed, and data from all published human studies and case reports were summarized for the validation of our predictions. Interventional and observational studies published in PubMed and two Chinese databases (CNKI and WanFang) through December 16, 2019, were included, and data were extracted for validation of the predictions. Using the BDDCS theory, class 3 active drugs were predicted to exhibit minimal interactions with rifampin. On reviewing case reports and pre-post studies, the predictions we made were found to be reliable. When antituberculosis medications that include rifampin are started in patients with hypertension, it is recommended that the use of calcium channel blockers and classes 1 and 2 β-blockers be avoided. Angiotensin-converting enzyme inhibitors, olmesartan, class 3 β-blockers, spironolactone, and hydrochlorothiazide would be preferable because clinically relevant interactions would not be expected.

CONCLUSION

Application of the BDDCS to predict interactions between rifampin and antihypertensive drugs for patients with both tuberculosis and hypertension was found to be reliable. It should be noted, however, that based on the CYP enzyme and drug transporter information we reviewed, the mechanisms of all of the interactions could not be elucidated, and the predictions are only based on theory. The real effects of rifampin on antihypertensive drugs need to be further observed. More studies in both animals and humans are needed in the future.

Effect of rifampin on enantioselective disposition and anti-hypertensive effect of benidipine

AIMS

In vitro study showed that benidipine is exclusively metabolized by cytochrome P450 (CYP) 3A. This study evaluated the effect of rifampin on the enantioselective disposition and anti-hypertensive effect of benidipine.

METHODS

Benidipine (8 mg) was administered to healthy subjects with or without repeated rifampin dosing, in a crossover design. Plasma concentrations of (S)-(S)-(+)-α and (R)-(R)-(-)-α isomers of benidipine and blood pressure were measured for up to 24 h after dosing. In addition, CYP3A metabolic capacity was evaluated in each subject using oral clearance of midazolam.

RESULTS

The exposure of (S)-(S)-(+)-α-benidipine was greater than that of (R)-(R)-(-)-α-benidipine by approximately three-fold following single dose of benidipine. Repeated doses of rifampin significantly decreased the exposure of both isomers. Geometric mean ratios (GMRs) (95% CI) of C_max and AUC_∞ for (S)-(S)-(+)-α-benidipine were 0.14 (0.10-0.18) and 0.12 (0.08-0.18), respectively. GMRs (95% CI) of C_max and AUC_∞ for (R)-(R)-(-)-α-benidipine were 0.10 (0.06-0.17) and 0.10 (0.06-0.17), respectively. Oral clearances of both isomers were increased equally by approximately 10-fold. There were no significant differences in cardiovascular effect following benidipine administration between control and rifampin treatment. CYP3A activity using midazolam did not appear to correlate with oral clearance of benidipine.

CONCLUSIONS

After single administration of racemic benidipine, enantioselective disposition of (S)-(S)-(+)-α- and (R)-(R)-(-)-α-benidipine was observed. Treatments with rifampin significantly decreased the exposure of both isomers but appeared to marginally affect its blood pressure-lowering effect in healthy subjects. Impact of coadministration of rifampin on the treatment effects of benidipine should be assessed in hypertensive patients.

Rifampicin reverses nicardipine effect inducing uncontrolled essential hypertension

Dihydropyridine calcium-channel blockers are a known substrate for the cytochrome P450 isoform 3A4. Rifampicin, an antitubercular agent, is one of the most potent inducers of hepatic and intestinal CYP3A4 thus increasing dihydropyridine metabolism. We report a case of a 67-year-old hypertensive female treated with a four-drug antihypertensive regimen including a dihydropyridine (nicardipine 50 mg bid), who was admitted for septic arthritis of the knee requiring antibiotic treatment with teicoplanin 400 mg od and rifampicin 600 mg bid. Six days after rifampicin initiation, she presented with Posterior Reversible Encephalopathy Syndrome due to uncontrolled hypertension. We hypothesized that disequilibrium of previously controlled hypertension was partially due to nicardipine ineffectiveness. Plasma nicardipine concentration was assessed through high-performance liquid chromatography 5 hours after coadministration of the two drugs and proved undetectable.