Biomedical subjects

R C Heintz

Publications and source records attributed to R C Heintz.

4 recordsLinked to original sources

PubMed1995

Tenoxicam and renal function.

The association of some nonsteroidal anti-inflammatory drugs (NSAIDs) with adverse effects on renal function has led to the need to systematically determine the risk of clinically relevant renal effects in patients treated with these drugs. Tenoxicam, an NSAID with established efficacy in the treatment of rheumatic diseases, has been studied in a variety of patient populations to evaluate its effects on renal function. Investigational studies, up to 5 years' duration, evaluated glomerular filtration renal blood flow and tubular function. There was no evidence of clinically relevant renal toxicity in patients with normal renal function, in elderly patients with age-related renal function, or in patients with mild to moderate renal impairment. There was, however, one patient with pre-existing renal pathology, who experienced raised plasma creatinine after 5 years of treatment. These findings are supported by an analysis of urinary system adverse effects in clinical trials that included over 67,000 patients, 25% of whom were elderly. The prevalence of these events, 0.07%, was similar in patients in both age groups. The most common events were dysuria and renal pain. Thus, patients treated long term with tenoxicam are at low risk for nephrotoxic effects. It is not recommended, however, that patients with severe pre-existing renal insufficiency receive tenoxicam.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1987

Overview on the pharmacokinetics of tenoxicam.

Tenoxicam, a new non-steroidal anti-inflammatory drug (NSAID) with an oxicam structure, is entirely ionised at physiological pH, has minimal lipophilic properties, high plasma protein binding, does not accumulate in fatty tissue and skin and thus has a small volume of distribution. Tenoxicam is rapidly and completely absorbed after oral administration. It is entirely metabolised via oxidation and conjugation pathways before elimination. The extraction ratio in the liver is small resulting in a long elimination half-life with a mean of 72 hours. Since no unchanged drug is found in the bile the low half-life cannot be explained by enterohepatic recirculation of parent compound. The low elimination rate of tenoxicam allows for a once-daily dosage (20 mg) regimen. Following multiple dosing during the first two weeks of therapy tenoxicam reaches steady-state levels within 10-20% of predicted values. Several pharmacokinetic factors help make tenoxicam therapy safe and straightforward: it is completely absorbed when taken orally even with meals or antacids, it penetrates easily into synovial fluid, and is excreted as inactive metabolites. Furthermore, drug disposition is not influenced by age, sex or rheumatic disease and unexpected accumulation is not observed.

Adult↗

PubMed1985

Lack of effect of tenoxicam on glibornuride kinetics and response.

The pharmacokinetics of glibornuride (25 mg i.v.) and the accompanying insulin and glucose responses were characterized in eight human subjects in the presence and absence of steady-state tenoxicam (20 mg p.o./day for 2 weeks). Tenoxicam affected neither the pharmacokinetic parameters of glibornuride (systemic clearance, volume of distribution and biological half-life) nor the responses of plasma insulin and blood glucose to glibornuride. The single i.v. dose of glibornuride had no detectable effect on the kinetics of tenoxicam.

Adult↗

PubMed1984

Pharmacokinetics of tenoxicam in healthy human volunteers.

Tenoxicam, a thieno-thiazine derivative, belongs to a new chemical class of non-steroidal anti-inflammatory drugs. Single dose kinetics was investigated after intravenous and oral administration to define the disposition and general absorption characteristics of the drug. After intravenous administration of 20 mg tenoxicam to 12 volunteers the time course of the plasma concentrations of unchanged drug followed two-compartment model characteristics. The area under the plasma-concentration time curve in the distribution phase contributed however only 3% or less to the total area. The plasma clearance was low with values ranging from 1.3 to 4.2 ml/min and the volume of distribution Vss was small averaging at 20 to 40% of the total body weight. The median half-life of elimination from the body was found to be 72 hours (range 42 to 100 hours). The disposition was not influenced by sex. Tenoxicam is highly bound to plasma albumin. At pH 7.4 the fraction bound exceeded 99% but was highly dependent on the pH. Plasma protein binding in patients with rheumatic disease was not different from that measured in healthy volunteers. The partitioning of tenoxicam into red blood cells was limited. Erythrocyte concentrations were only 20-30% of the corresponding plasma concentrations. After oral administration of a 20-mg tablet complete and rapid absorption of the drug was observed with maximum plasma levels of 1.7 to 3.6 micrograms/ml reached within 0.5 to 2 hours. Due to the rapid absorption and terminal half-life of the drug its plasma concentration profile after oral administration was very similar to that following intravenous dosing. The pharmacokinetic characteristics of tenoxicam offers a rationale to administer the entire dose in one single portion.

Administration, Oral↗