No clinically relevant drug interaction between paracetamol and phenprocoumon based on a pharmacoepidemiological cohort study in medical inpatients

Fattinger, Karin; Frisullo, Roberto; Masche, Urspeter; Braunschweig, Suzanne; Meier, Peter J.; Roos, Małgorzata

doi:10.1007/s00228-001-0404-7

Cited by 18 publications

(12 citation statements)

References 17 publications

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“…Most participants did not know which OTC analgesic is safe for patients with OAT and even worse some indicated they would buy aspirin or other OTC NSAIDs. Only 20% were aware that paracetamol (acetaminophen) is considered the safest OTC analgesic for patients on OAT with phenprocoumon [30,31]. This lack of knowledge is particularly worrisome since two thirds of the participants indicated they would not inform pharmacists about concomitant use of OAT when purchasing OTC medication.…”

Section: Discussionmentioning

confidence: 99%

Safety relevant knowledge of orally anticoagulated patients without self-monitoring: a baseline survey in primary care

et al. 2014

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BackgroundEffective and safe management of oral anticoagulant treatment (OAT) requires a high level of patient knowledge and adherence. The aim of this study was to assess patient knowledge about OAT and factors associated with patient knowledge.MethodsThis is a baseline survey of a cluster-randomized controlled trial in 22 general practices with an educational intervention for patients or their caregivers. We assessed knowledge about general information on OAT and key facts regarding nutrition, drug-interactions and other safety precautions of 345 patients at baseline.ResultsParticipants rated their knowledge about OAT as excellent to good (56%), moderate (36%) or poor (8%). However, there was a discrepancy between self-rated knowledge and evaluated actual knowledge and we observed serious knowledge gaps. Half of the participants (49%) were unaware of dietary recommendations. The majority (80%) did not know which non-prescription analgesic is the safest and 73% indicated they would not inform pharmacists about OAT. Many participants (35-75%) would not recognize important emergency situations. After adjustment in a multivariate analysis, older age and less than 10 years education remained significantly associated with lower overall score, but not with self-rated knowledge.ConclusionsPatients have relevant knowledge gaps, potentially affecting safe and effective OAT. There is a need to assess patient knowledge and for structured education programs.Trial registrationDeutsches Register Klinischer Studien (German Clinical Trials Register): DRKS00000586.Universal Trial Number (UTN U1111-1118-3464).

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Section: Discussionmentioning

confidence: 99%

Safety relevant knowledge of orally anticoagulated patients without self-monitoring: a baseline survey in primary care

et al. 2014

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“…It is of importance to know whether there is an interaction between oral anticoagulation and paracetamol since paracetamol is the first‐line analgesic and antipyretic therapy in patients receiving oral anticoagulation. A recent literature review shows that the methodology used varies widely: retrospective, observational or case–control studies, case reports or experimental studies in healthy subjects suggest the occurrence of an increase in the anticoagulant effect of oral anticoagulation by paracetamol [4, 6–8, 13, 14], while others do not [12, 15, 16]. But all these studies are subject to caution due to methodological biases (retrospective studies, few patients, patients not reflecting those encountered in normal clinical practice) and variable therapies (warfarin but also fluindione, acenocoumarol, phenprocoumon, coumarins).…”

Section: Discussionmentioning

confidence: 99%

“…It is of importance to know whether there is an interaction between oral anticoagulation and paracetamol since paracetamol is the first-line analgesic and antipyretic therapy in patients receiving oral anticoagulation. A recent literature review shows that the methodology used varies widely: retrospective, observational or case-control studies, case reports or experimental studies in healthy subjects suggest the occurrence of an increase in the anticoagulant effect of oral anticoagulation by paracetamol [4, 6-8, 13, 14], while others do not [12,15,16].…”

Section: Discussionmentioning

confidence: 99%

Paracetamol: a haemorrhagic risk factor in patients on warfarin

Mahé¹,

Bertrand²,

Drouet

et al. 2005

Brit J Clinical Pharma

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AimTo quantify the effect of paracetamol on the anticoagulant effect of war farin under normal clinical conditions. Patients and methodsIn a prospective double-blind, cross-over, placebo-controlled study, 11 patients on stable warfarin therapy received in random order two 14-day regimens of paracetamol 4 g day − 1 or placebo, with a 14-day or more wash-out period in between, time necessary to fulfil the inclusion criteria. ResultsIn patients on paracetamol, the mean maximum increase in the International Normalized Ratio (INR) observed was 1.04 ± 0.55 vs. 0.20 ± 0.32 in those on placebo ( P = 0.003). The mean maximum INR observed was significantly higher with paracetamol than with placebo (3.47 vs. 2.61, P = 0.01). In patients receiving paracetamol, the mean observed INR was significantly increased after 4 days ( + 0.6 ± 0.6, P < 0.001). ConclusionParacetamol at 4 g day − 1 induces a significant increase in INR in patients receiving a stable regimen of warfarin, increasing the risk of bleeding associated with warfarin.

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“…Gingival bleeding and hematuria were observed when paracetamol was given with warfarin (Hylek et al, 1998). Several case reports including case controlled studies have reported that paracetamol potentiates the anti-coagulant effect of warfarin (Andrews, 2002), others have not found a clinically relevant interaction (Fattinger et al, 2002). NSAIDs such as mefenamic acid (Holemes, 1966), etodolac (Ermer et al, 1994), ibuprofen (Penner and Abdrecht, 1975;Schulman and Henriksson, 1989) and tenidap (Apseloff et al, 1995) may also displace coumarin anti-coagulants from protein binding sites.…”

Section: Resultsmentioning

confidence: 99%

Effect of arsenic on paracetamol binding to bovine serum albumin using site specific probes

Uddin

Saffoon²,

Alam

2012

Int Curr Pharm J

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Arsenic contamination in groundwater is a global health challenge. A large number of people worldwide are affected by arsenic poisoning. Paracetamol is a widely used analgesic-antipyretic drug. Effect of arsenic on paracetamol binding to protein has been investigated using two site specific probes and equilibrium dialysis method was used for the experiment. In absence of any site specific probes free concentration of paracetamol bound to bovine serum albumin increased from 3.95 ± 1.164% to 25.36 ± 1.164%. In presence of site-I specific probe warfarin sodium the % release of drug was steady at around 14%. But in presence of site-II specific probe an increment of free drug concentration was observed from 14.38 ± 1.164% to 54.72 ± 1.552%. Thus it can be assumed that the free concentration of paracetamol was increased to a greater extent in presence of arsenic and probably arsenic bound to site-II of BSA. Thus arsenic may displace paracetamol by binding with high affinity binding site, site-II in the BSA and probably arsenic has little effect to site-I.

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No clinically relevant drug interaction between paracetamol and phenprocoumon based on a pharmacoepidemiological cohort study in medical inpatients

Abstract: These results suggest that paracetamol co-administration at a dosage of 2000-2500 mg/day for 3 days has no clinically relevant effects on the anticoagulant effects of phenprocoumon.

Cited by 18 publications

References 17 publications

Safety relevant knowledge of orally anticoagulated patients without self-monitoring: a baseline survey in primary care

Safety relevant knowledge of orally anticoagulated patients without self-monitoring: a baseline survey in primary care

Paracetamol: a haemorrhagic risk factor in patients on warfarin

Effect of arsenic on paracetamol binding to bovine serum albumin using site specific probes

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