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Biomedical subjects

T Pullar

Publications and source records attributed to T Pullar.

At least 55 records · Page 3Linked to original sources

Time to stop counting the tablets?

We attempted to assess compliance using both a pharmacologic indicator (low-dose phenobarbital) and a return tablet count in 225 patients who were taking part in three separate studies. There were 216 patients (96%) who kept a follow-up appointment after 28 days; 161 patients appeared to have good compliance (90% to 109%) by return tablet count. Of these 161 patients, 51 (32%) had plasma phenobarbital concentrations (corrected for dose and weight) that were less than 90% of the lowest value previously found in normal volunteers, which suggested poorer compliance. When compared with the age-related volunteer values, 77 (48%) had values that were less than 90% of the lowest volunteer value. There were 6 of 10 patients with apparently excessive (greater than or equal to 110%) compliance by return tablet count and 4 of 12 who failed to return their container who also had phenobarbital concentrations that were less than 90% of the lowest volunteer value. We concluded that return tablet count grossly overestimates compliance.

Drug Therapy↗

A study of tolerance to the psychomotor effects of indomethacin in healthy volunteers.

We have examined the effect of single dose indomethacin 50 mg on objective measurements of psychomotor function and whether this effect is altered by pretreatment with indomethacin 25 mg t.i.d. for 7 days in 10 healthy volunteers (5 male, 5 female; age 20-54 y). One hour after a single dose of indomethacin 50 mg there was significant impairment of psychomotor function (critical flicker fusion frequency threshold and choice reaction time) (Wilcoxon p less than 0.05). Pretreatment with indomethacin 25 mg t.i.d. for 7 days prevented this impairment. Thus we conclude that tolerance occurs over the course of a week to the psychomotor effects of indomethacin.

Adult↗

Patients' knowledge concerning their medications on discharge from hospital.

Fifty patients were interviewed, on discharge from hospital, about their medications. Nine (18%) patients did not know, and a further four (8%) had inappropriate beliefs about why they were taking at least one of their discharge medications. Very few patients knew of significant side-effects which they might expect, or precautions which they should take, and over half did not know how long they were to continue taking their medicines. A small proportion was unable to read the bottle or open the container. Thus, even patients who, by virtue of an in-patient stay, have had a prolonged opportunity for education regarding their medicines have very little knowledge of their medicines upon discharge from hospital.

Drug Therapy↗

Compliance in clinical trials.

Compliance with treatment can be an important determinant of the outcome of clinical trials. To date there is no completely satisfactory method of measuring compliance and some of the most widely used methods are inadequate. The various methods of measuring compliance and how they have been applied to clinical trials are described, and improvements in the standard of the measurement and reporting of compliance in clinical trials are suggested.

Anti-Inflammatory Agents, Non-Steroidal↗

Use of a pharmacologic indicator to compare compliance with tablets prescribed to be taken once, twice, or three times daily.

By use of an interview, return tablet count, and a pharmacologic indicator (low-dose phenobarbital), we compared compliance with tablets prescribed to be taken once, twice, or three times daily. One hundred seventy-nine patients with type II diabetes were randomly allocated to take one 2 mg phenobarbital tablet once, twice, or three times daily for 28 days. Phenobarbital level/dose ratios indicated that compliance was similar with once- and twice-daily regimens, and both were better than thrice-daily dosing. Mean return tablet counts suggested that compliance was best with the once-daily regimen; both twice- and thrice-daily regimens were similarly inferior. This difference between the techniques may be explained by the inadequacies of the residual tablet count, which identified only 13% of cases identified by phenobarbital. We conclude that compliance with the once-daily regimen was best, but that compliance with a twice-daily regimen was very similar, and both were superior to dosing three times a day.

Drug Administration Schedule↗

The effect of indomethacin on the psychomotor function of patients with rheumatic diseases.

We have compared the effect of single and multiple doses of indomethacin and placebo on objective measurements of psychomotor impairment in patients. Following a single 50 mg dose (n = 8), indomethacin produced psychomotor disturbance in only those patients who had no recent history of NSAID exposure. After multiple doses of indomethacin (25 and 50 mg tid for 5 days), significant psychomotor impairment was observed. We conclude that other NSAIDs may induce cross-tolerance to the psychomotor effects of indomethacin. Tachyphylaxis may develop to the psychomotor disturbance caused by indomethacin.

Arthritis, Rheumatoid↗

The use of a pharmacological indicator to investigate compliance in patients with a poor response to antirheumatic therapy.

Twenty-six patients with rheumatoid arthritis which was poorly controlled despite high dose D-penicillamine were studied. Compliance was assessed by standard methods (return tablet count and interview). In addition low-dose phenobarbitone was included in the penicillamine formulation as a pharmacological indicator of compliance. Using these techniques incomplete compliance was apparent in 11 patients (42%). All such patients were identified by the pharmacological marker. Only one admitted poor compliance at interview and only six returned more than a few tablets too many. The reason for the high incidence of poor compliance in this selected group is not apparent but it may represent a significant cause of failure with D-penicillamine therapy. The use of low-dose phenobarbitone may have wider applications in the investigation of patients with other conditions who fail to respond adequately to treatment.

Adult↗

The effect of allopurinol on the steady-state pharmacokinetics of indomethacin.

The effect of 5 days treatment with allopurinol (300 mg) on the pharmacokinetics of indomethacin at steady-state was investigated in eight patients. Allopurinol produced no significant effect on the indomethacin serum concentration-time curve. Allopurinol did not alter significantly the amounts of indomethacin excreted in the urine within 8 h. However, the urinary ratio of N-deschlorobenzoylindomethacin to indomethacin was reduced significantly by allopurinol administration (P less than 0.05).

Adult↗

Measuring treatment compliance of men with non-gonococcal urethritis receiving oxytetracycline combined with low dose phenobarbitone.

Of 62 men with non-gonococcal urethritis who entered a study to assess compliance with treatment with oxytetracycline, only 33 could be evaluated. Traditional methods (interview and the absence of oxytetracycline in the urine) showed incomplete compliance in nine. Use of low dose phenobarbitone as a pharmacological marker showed incomplete compliance in a further five patients. In addition, phenobarbitone concentrations gave information on the extent to which individual patients had omitted treatment and provided direct, as opposed to circumstantial, evidence of good compliance by most (18) of those studied. Only three of the 33 patients whose compliance was assessed had evidence of continuing infection at follow up, and there was evidence of incomplete compliance in only one of these patients.

Adolescent↗

Alteration of thiol and superoxide dismutase status in rheumatoid arthritis treated with sulphasalazine.

Intracellular thiols (LSH), superoxide dismutase (SOD) and plasma thiols (PSH) are thought to have an important role in the protection of tissues from damage by oxygen-derived free radicals. The change in the levels of activity of these substances in patients with active rheumatoid arthritis treated with sulphasalazine for 6 months was assessed in 22 patients. Over this time there was a marked improvement in disease activity. This was accompanied by an early increase in red cell LSH and decrease in SOD, although by 6 months these changes had completely reversed. In addition the negative correlation between these indices at week 0 had disappeared by week 6. Over the 6 months there was a steady rise in PSH. The change in PSH is slow and is thus more likely to reflect a change in the disease process rather than an active role for the thiol, but the early changes in intracellular parameters may be of importance in the action of this drug. These changes are similar to changes found with other second-line drugs. It is also of interest that a drug which does not itself possess a thiol group is capable of altering the thiol status of cells.

Adult↗

N-desmethylclobazam: a possible alternative to clobazam in the treatment of refractory epilepsy?

The development of anticonvulsant tolerance during 10 days treatment with either clobazam or its principal metabolite, N-desmethylclobazam (NDMC), was compared in mice using an i.v. infusion of pentylenetetrazole as the convulsive stimulus. Subsequently the anticonvulsant activity of NDMC was assessed in patients with refractory epilepsy. In mice, a highly significant tolerance (P less than 0.001) developed to clobazam (10 mg kg-1 twice daily). During the same period, there was no significant change (P greater than 0.05) in the protection afforded by NDMC (40 or 80 mg kg-1 twice daily) although some reduction in anticonvulsant activity was apparent. NDMC (30 mg once daily) was given to nine patients with frequent complex partial and/or grand mal seizures who had become tolerant to the anticonvulsant effect of clobazam. Seven of the patients had been free from benzodiazepine therapy for at least 2 weeks, while the other two patients were switched directly from clobazam. Eight of the nine patients showed a favourable response to NDMC. In the seven who had been given a holiday from clobazam the response to NDMC was similar to the initial response to clobazam and was achieved at plasma NDMC concentrations in the same range as those seen during clobazam administration (1000-3000 ng ml-1). It is concluded that NDMC is active as an anticonvulsant in man and there is evidence from the animal studies to suggest that it may be preferable to clobazam.

Adult↗

The effect of cimetidine on the single dose pharmacokinetics of oral clobazam and N-desmethylclobazam.

The effect of cimetidine on the single dose pharmacokinetics of orally administered clobazam and N-desmethylclobazam (NDMC) was studied in volunteers. Cimetidine inhibited the elimination of both clobazam and NDMC and inhibited the rate of formation of NDMC from clobazam. The increase in the AUC for NDMC generated from clobazam was relatively greater than that for clobazam itself. This suggests that NDMC elimination is inhibited to a relatively greater extent than clobazam elimination. The increase in AUC for NDMC generated from clobazam was also relatively greater than that for NDMC administered orally. This would suggest that cimetidine either increases the bioavailability of clobazam or reduces that of NDMC. The increases in the AUC for NDMC and for clobazam in some individuals was of a magnitude which is likely to be clinically significant.

Adult↗

Pharmacokinetics of N-desmethylclobazam in healthy volunteers and patients with epilepsy.

1. The single dose pharmacokinetics of N-desmethylclobazam (NDMC) and clobazam were studied in eight healthy male volunteers. 2. Steady-state pharmacokinetic data are described from four healthy male volunteers and eight epileptic patients taking NDMC. 3. A single 30 mg dose of NDMC produced a greater Cmax (P less than 0.001) and AUC0-infinity (P less than 0.005) and a shorter tmax (P less than 0.05) and t1/2 (P less than 0.01) for NDMC than did 30 mg clobazam. 4. Mean steady-state NDMC concentrations were greater in male patients than in female patients and also in male patients compared with male volunteers. The differences between patients and volunteers might be explained by concomitant antiepileptic medication.

Adult↗