Determinants of adherence in a cohort of Belgian HIV patients: a pilot study.

Since the era of highly active antiretroviral therapy (HAART), HIV is considered a chronic disease. Adherence to HAART is crucial for effectiveness. Non-adherence negatively impacts patient outcome and the larger economy. However, data on adherence among the Belgian HIV cohort are scarce. Therefore, the purpose of this pilot study was to identify determinants of adherence among HIV patients treated in Belgium. The study was conducted at the Aids Reference Centre of Ghent University Hospital between 1 January and 31 December 2012. Sociodemographic data were collected, along with the Simplified Medication Adherence Questionnaire (SMAQ), the Center for Adherence Support Evaluation (CASE) Adherence Index, the EuroQol-6D, the Medical Outcomes Study-HIV (MOS-HIV), the Beck Depression Inventory-II, and three neurocognitive complaints screening questions. To date, 218 patients participated in the study, among whom 173 (79·4%) were male. Mean age was 46·0±10·6 years and 133 patients (63·9%) were homosexual. According to the SMAQ and the CASE, 78·5% and 93·5% of the patients were adherent to antiretroviral therapy. Logistic regression analysis revealed that smoking, neurocognitive complaints, and female sex were independent determinants of non-adherence. In conclusion, there is an elevated risk for non-adherence in smokers, people experiencing neurocognitive problems, and women in our sample. The latter could reflect differences between male and female HIV patients in Belgium. Adherence improving initiatives should be tailored to these three risk groups.

Influence of acetylsalicylic acid and ketoprofen on canine thyroid function tests.

Many factors including drugs can influence thyroid function in humans, rats and dogs. Studies in humans report significant effects of non-steroidal anti-inflammatory agents (NSAIDs) on thyroid function tests, which can lead to misinterpretation of the results and inappropriate therapeutic decisions. As NSAIDs are used more and more frequently in dogs, it is important to know to what extent they can influence results. Eighteen spayed female beagle dogs were randomly assigned to three treatment sequences in a 3 x 3 crossover study design with treatments consisting of acetylsalicylic acid (ASA) (25 mg/kg BW q 12 h), ketoprofen (Keto) (1 mg/kg BW q 24 h) or placebo administered for a 1-week period with a 3-week washout period between treatment periods. Blood samples for determination of total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3), thyrotropin (TSH), reverse triiodothyronine (rT3), Keto and ASA concentrations were taken during each treatment period on days 0, 1, 3 and 7. During the washout period samples were taken weekly. A significant decrease in TT4 was observed as soon as 24 h after ASA administration, whereas the decrease in TT3 was less pronounced and differed significantly from the placebo only after 1 week of administration. No significant effects were found for free T4 and TSH with ASA administration. No significant effects on thyroid results were found following Keto administration. The results indicate that TT4 can be markedly decreased by ASA therapy and until the results of further studies are available, thyroid function test results should be interpreted cautiously in dogs on NSAIDs therapy.

Evaluation of thyroid function in obese dogs and in dogs undergoing a weight loss protocol.

Obesity and weight loss have been shown to alter thyroid hormone homeostasis in humans. In dogs, obesity is the most common nutritional problem encountered and weight loss is the cornerstone of its treatment. Therefore, it is important to clarify how obesity and weight loss can affect thyroid function test results in that species. The objectives of this study were to compare thyroid function in obese dogs and in lean dogs and to explore the effects of caloric restriction and weight loss on thyroid hormone serum concentrations in obese dogs. In the first experiment, 12 healthy lean beagles and 12 obese beagles were compared. Thyroid function was evaluated by measuring serum concentrations of total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3), thyrotropin (TSH), and reverse triiodothyronine (rT3) as well as a TSH stimulation test using 75 microg i.v. of recombinant human TSH. In the second experiment, eight obese beagles were fed an energy-restricted diet [average 63% maintenance energy requirement (MER)] until optimal weight was obtained. Blood samples for determination of TT4, FT4, TT3, TSH and rT3, were taken at the start and then weekly during weight loss. Only TT3 and TT4 serum concentrations were significantly higher in obese dogs as compared to lean dogs. In the second experiment, weight loss resulted in a significant decrease in TT3 and TSH serum concentrations. Thus obesity and energy restriction significantly alter thyroid homeostasis in dogs, but the observed changes are unlikely to affect interpretation of thyroid function test results in clinics.

The influence of ventilation mode (spontaneous ventilation, IPPV and PEEP) on cardiopulmonary parameters in sevoflurane anaesthetized dogs.

The purpose of this study was to investigate the cardiopulmonary influences of sevoflurane in oxygen at two anaesthetic concentrations (1.5 and 2 MAC) during spontaneous and controlled ventilation in dogs. After premedication with fentany-droperidol (5 microg/kg and 0.25 mg/kg intramuscularly) and induction with propofol (6 mg/kg intravenously) six dogs were anaesthetized for 3 h. Three types of ventilation were compared: spontaneous ventilation (SpV), intermittent positive pressure ventilation (IPPV), and positive end expiratory pressure ventilation (PEEP, 5 cm H2O). Heart rate, haemoglobin oxygen saturation, arterial blood pressures, right atrial and pulmonary arterial pressures, pulmonary capillary wedge pressure and cardiac output were measured. End tidal CO2%, inspiratory oxygen fraction, respiration rate and tidal volume were recorded using a multi-gas analyser and a respirometer. Acid-base and blood gas analyses were performed. Cardiac index, stroke volume, stroke index, systemic and pulmonary vascular resistance, left and right ventricular stroke work index were calculated. Increasing the MAC value during sevoflurane anaesthesia with spontaneous ventilation induced a marked cardiopulmonary depression; on the other hand, heart rate increased significantly, but the increases were not clinically relevant. The influences of artificial respiration on cardiopulmonary parameters during 1.5 MAC sevoflurane anaesthesia were minimal. In contrast, PEEP ventilation during 2 MAC concentration had more pronounced negative influences, especially on right cardiac parameters. In conclusion, at 1.5 MAC, a surgical anaesthesia level, sevoflurane can be used safely in healthy dogs during spontaneous and controlled ventilation (IPPV and PEEP of 5 cm H2O).

Influence of lignocaine on plasma protein binding and pharmacokinetics of verapamil in dogs.

The effect of lignocaine (lidocaine) on the plasma protein binding of verapamil has been studied in-vitro and in-vivo in dogs. The binding of verapamil was ca 85%. In-vitro addition of lignocaine at therapeutic concentrations displaced verapamil from its plasma binding sites. Lignocaine in this regard was equipotent with tris(2-butoxyethyl)phosphate, suggesting an interaction at the level of alpha 1-acid glycoprotein binding sites. On in-vivo administration of 4 mg kg-1 in a bolus to dogs in which steady state concentrations of verapamil were present, the free fraction of verapamil increased transiently. During the lignocaine maintenance infusion, it then decreased to a level higher than that before administration of the local anaesthetic. The free verapamil concentrations increased suddenly upon the administration of the lignocaine loading dose, and then returned to values slightly higher than those before lignocaine. After a bolus injection of verapamil during a lignocaine infusion, the verapamil total plasma concentrations were lower than during a saline infusion, but the free concentrations were not different. The volume of distribution of verapamil was increased, whereas the blood clearance had not changed; the lignocaine infusion did not change the hepatic blood flow, as measured by indocyanine green clearance. These results show that lignocaine displaces verapamil in-vitro and in-vivo from its plasma protein binding sites, but the ensuing pharmacokinetic changes do not lead to significant changes in free verapamil concentrations.

Influence of inflammation on serum concentration, molecular heterogeneity and drug binding properties of canine alpha-1-acid glycoprotein.

The concentration and the heterogeneity of alpha-1-acid glycoprotein (alpha-1-AGP) and oxprenolol binding were determined in serum of healthy dogs and dogs with inflammatory disease. In inflammation, an increase in the mean alpha-1-AGP concentration from 0.47 to 2.85 g/l was accompanied by a reduction in the mean free oxprenolol fraction from 25% to 6%. alpha-1-AGP concentration and oxprenolol binding were inversely correlated. The heterogeneity of canine alpha-1-AGP remained essentially unchanged in dogs with inflammation and, in both these dogs and the controls, between five and seven forms with different isoelectric points and one single concanavalin A-reactive form were detected. It is concluded that in dogs, as in humans, oxprenolol binds to serum alpha-1-AGP. Changes in serum binding of oxprenolol during inflammation result from a change in the serum concentration of alpha-1-AGP rather than a change of molecular heterogeneity.

Influence of enhanced alpha-1-acid glycoprotein concentration on protein binding, pharmacokinetics and antiarrhythmic effect of lidocaine in the dog.

The pharmacokinetics and the antiarrhythmic effect of lidocaine were studied in healthy dogs on three occasions: before administration of rifampicin, on the 14th day of treatment with rifampicin and 4 weeks after stopping rifampicin treatment. On each occasion a loading and a maintenance infusion of lidocaine were given to obtain steady-state concentrations. Blood and plasma concentrations of lidocaine, alpha-1-acid glycoprotein plasma concentrations and percentage of free lidocaine in plasma were determined at the end of the maintenance infusion. The antiarrhythmic effect of lidocaine was evaluated by measuring the arrhythmogenic dose of epinephrine. Blood concentrations and, consequently, the total blood clearance of lidocaine were comparable on the three occasions. Total plasma concentrations were significantly higher after rifampicin administration as compared to the two control periods. Percentage of free lidocaine decreased from about 50 to about 30%, accompanied by a nearly 3-fold increase of alpha-1-acid glycoprotein concentrations. Free plasma concentrations were slightly lower after rifampicin treatment. The epinephrine dose ratio (before/after) paralleled the changes in free lidocaine concentrations. The correlation between free plasma concentrations and epinephrine dose ratio was much stronger than between total plasma concentrations and epinephrine dose ratio. The plasma elimination half-life of lidocaine was markedly shortened after rifampicin treatment, due to a diminished volume of distribution. It is concluded that, under steady-state conditions, marked increases in the protein binding of lidocaine are accompanied by only slight decreases of free plasma concentrations and of antiarrhythmic effect.

Alpha 1-acid glycoprotein and serum binding of drugs in healthy and diseased dogs.

Inter-individual variation in drug serum protein binding was studied in healthy dogs and in dogs with inflammatory diseases for lidocaine, oxprenolol and propranolol, which bind mainly to alpha 1-acid glycoprotein (alpha 1-AGP), and for diazepam, digitoxin and phenytoin, which bind mainly to albumin. For the drugs mostly bound to alpha 1-AGP, in both groups of dogs binding varied considerably, and it was markedly higher in dogs with inflammatory disease. For the other drugs, the variation in binding was smaller and did not differ between the two groups of dogs. In both groups of dogs, the alpha 1-AGP concentration varied widely; it was higher in the serum of the dogs with inflammation, while the concentration of albumin was lower in these animals. There was a significant negative correlation between percentage free lidocaine, oxprenolol or propranolol and alpha 1-AGP concentration, suggesting that the inter-individual variation in binding of these drugs is due to the variation in alpha 1-AGP concentration. There was a marked intra-individual variation in lidocaine binding and in serum alpha 1-AGP concentration, studied over a period of 3 weeks in healthy dogs; a significant negative correlation between percentage free lidocaine and alpha 1-AGP concentration was obtained.

Digoxin-quinidine interaction in the dog.

In seven healthy dogs, digoxin was given as an oral loading dose (0.05 mg/kg/day) on the first day, followed by an oral maintenance dose (0.02 mg/kg/day) during the next 14 days. On the sixth day of digoxin treatment, oral quinidine (200 mg b.i.d.) was added until the tenth day. Plasma concentrations of digoxin and quinidine were measured; in three of the seven dogs ECG and physical signs of digitalis toxicity were evaluated. The average steady state plasma concentration of digoxin increased significantly (P less than 0.01) during quinidine administration (from 1.4 to 2.3 ng/ml). On the days that digoxin was administered without quinidine, none of the dogs vomited nor was anorectic; the PQ-interval increased significantly (P less than 0.01) between 0.01 and 0.03 s. When quinidine was added, vomiting and anorexia occurred but no further increases in the PQ-interval were seen.

Lidocaine plasma concentrations obtained with a standardized infusion in the awake and anaesthetized dog.

Lidocaine was administered intravenously on several occasions to three healthy mongrel dogs. The lidocaine treatment consisted of an infusion of 0.8 mg/kg/min over 10 min, followed by an infusion of 0.085 mg/kg/min over 3 h. This lidocaine treatment was given once in the awake state and on two other occasions the infusion was started before or during the following anaesthetic regimen: atropine-meperidine premedication, thiopental induction and maintenance nitrous oxide-methoxyflurane anaesthesia. In most instances plasma levels were somewhat higher at the end of the loading infusion (greater than 5 micrograms/ml) than subsequently, but steady-state values were obtained soon after starting the 3-h infusion. There were no striking differences between the plasma profiles and half-lives found in the three series of experiments: mean plasma concentrations of lidocaine during steady state were between 3.5 and 5.0 micrograms/ml and the half-life of lidocaine was 1 to 2 h. Signs of intoxication were not seen in any of the dogs at any stage of the procedures. It is concluded that with the loading and maintenance doses used in this study steady-state values, probably within the therapeutic range, are obtained within a few minutes. The plasma concentrations are not influenced by the anaesthetic regimen used.

In-vivo diagnosis of right renal aplasia in a pekingese bitch.

The physical, haematological, urinary and radiographic findings in a female pekingese dog with right renal aplasia are described. The right ureter was present and structurally normal. The left kidney was hypertrophied. The ovaries and uterus were normal.