The influence of age on the response to anticoagulants.

1 To determine whether two different oral anticoagulants show difference under routine clinical conditions, 71 patients were randomized to treatment with Apekumarol, a microcrystalline dicoumarol preparation, and 72 patients to treatment with warfarin. 2 During the inpatient phase of treatment both drug groups remained for about 94% of their treatment time within prothrombin value limits of 5‐25% (Simplastin A). No statistically significant difference was found between the drugs. 3 While under outpatient care, both drug groups remained for about 80% of their treatment time within prothrombin value limits of 5‐25%. No statistically significant difference was found between the drugs. 4 The intensity of control and number of prothrombin‐ determinations did not differ significantly between the groups. 5 Variations in the daily dose did not differ significantly between the groups. 6 The mean daily dose could not be correlated to mean body weight. 7 The mean daily dose decreased with age for the male patients taking warfarin, not for the female patients. There was no such decrease for either male or female patients taking Apekumarol. An additional 137 patients who at the time of the trial were under routine treatment with warfarin were also studied with regard to mean daily dose, age and sex. In this additional group the mean daily dose could be correlated with age in both males and females. 8 No difference between Apekumarol and warfarin could be demonstrated when tested under routine clinical conditions according to the design of the present study. Sensitivity for warfarin, but not for Apekumarol, seems to increase with age, this sensitivity has been demonstrated in both sexes.

Section: Methodsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of a new microcrystalline dicoumarol preparation with warfarin under routine treatment conditions.

Lockner¹,

Paul²

1979

“…Acenocoumarol daily dose expressed in mg/kg fell with increasing age, this decrease being most pronounced from the third to the fifth decade (see Table 5). Variations in the degree Husted & Andreasen (1977) found that the daily maintenance dose of both phenprocoumon, bishydroxycoumarin and warfarin in 114 patients on long-term anticoagulant therapy was significantly lower in patients aged between 61 and 70 years than in those between 50 and 60 years. However, when expressed on a weight basis, the mean daily dose of bishydroxycoumarin was not significantly lower in the elderly.…”

Section: Discussionmentioning

confidence: 99%

Effect of age and sex on acenocoumarol requirements.

Arboix¹,

Laporte²,

Frati³

et al. 1984

1 A group of 690 patients (337 males and 353 females) on long-term acenocoumarol therapy was studied. 2 62.8% of the values of the prothrombin ratio were within the chosen therapeutic range (1.8 to 2.7), 21.9% were below 1.8 and 15.3% were above 2.7. 3 The daily maintenance dose, expressed on a weight basis, was found to significantly decrease with increasing age. 4 The daily maintenance dose taken by females was significantly higher than the dose taken by males (P < 0.05); the differences between males and females were maximal among patients aged between 21 and 50 years, and disappeared at older ages. 5 Two hundred and twenty-eight haemorrhagic episodes in 160 patients were recorded during a total of 7797 months of follow-up. No lethal haemorrhages were observed. The overall incidence of bleeding episodes among females (3.6%) was higher than among males (2.2%) (P < 0.001), even if menorrhagia was excluded (P < 0.01).

“…For some of them, for example age, the direction and the degree with which they interfere with the effects of oral anticoagulants has been determined with some precision (O'Malley et al, 1977;Husted & Andreasen, 1977;Shepherd et al, 1977;Routledge et al, 1979). Other factors such as sex and indication for treatment remain controversial and uncertain (O'Malley et al, 1977;Routledge et al, 1979;Arboix et al, 1984).…”

Section: Discussionmentioning

confidence: 99%

The potentiation of acenocoumarol anticoagulant effect by amiodarone.

Arboix¹,

Frati²,

Laporte³

1984

I Out of 690 patients (337 males and 353 females) on long-term acenocoumarol therapy, 80 (35 males and 45 females) were taking amiodarone. Forty patients had started amiodarone treatment while being treated with acenocoumarol. Of these, nine patients had begun amiodarone treatment while taking acenocoumarol. 2 The relation between the daily dose of acenocoumarol and the prothrombin ratio (AC dose/PR ratio) has been considered a useful indicator to study the interaction between amiodarone and acenocoumarol. 3 Differences of acenocoumarol daily dose between takers and non-takers of amiodarone were statistically significant (t = 5.35; P < 0.001) for the whole population, for all the age groups, and also among males (t = 2.43; P < 0.01) as well as among females (t =5.38;P<0.001). 4 Out of 40 patients chronically treated with acenocoumarol in whom amiodarone was instituted, 32 showed a decrease of the AC dose/PR ratio, while in eight patients no change was recorded (paired t-test, t = 5.82; P < 0.001). 5In 15 patients who were being concomitantly treated with acenocoumarol and amiodarone, amiodarone was discontinued. An increase of the AC dose/PR ratio was recorded (paired t-test, t = 4.01; P < 0.001). 6 Nine patients had started treatment with amiodarone while receiving acenocoumarol and a decrease of the AC dose/PR ratio was documented; amiodarone was discontinued some months later, and an increase of the AC dose/PR ratio was seen.