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J J Lohman

Publications and source records attributed to J J Lohman.

15 recordsLinked to original sources
PubMed1999

Bioavailability of intranasal formulations of dihydroergotamine.

OBJECTIVE: A comparison of the pharmacokinetic properties of two novel intranasal preparations of dihydroergotamine mesilate (DHEM) with a commercially available intranasal preparation. METHODS: Two intranasal formulations of DHEM in combination with randomly methylated beta-cyclodextrin (RAMEB) were prepared. Subsequently, in an open, randomised, crossover study in nine healthy volunteers, the following medication was administered: 2 mg DHEM/2% RAMEB nasal spray (= two puffs of 100 microliters); 2 mg DHEM/4 mg RAMEB nasal powder; 2 mg Diergo nasal spray (= four puffs of 125 microliters); 0.5 mg DHEM i.m., and 2 mg DHEM solution p.o. RESULTS: No statistically significant differences were found in maximum plasma concentration (Cmax), time to reach Cmax (tmax), area under plasma concentration-time curve (AUC0-8 h), Frel(t = 8 h) and Cmax/AUC(t = 8 h) for the three intranasal preparations. The relative bioavailabilities of the DHEM/RAMEB nasal spray, the DHEM/RAMEB nasal powder and the commercially available DHEM nasal spray were 25%, 19% and 21%, respectively, in comparison with i.m. administration. The relative bioavailability after oral administration was 8%. CONCLUSION: The pharmacokinetic properties of the novel intranasal preparations are not significantly different from the commercially available nasal spray. Advantages of the DHEM/RAMEB nasal spray are (1) less complicated handling, (2) reduction of the number of puffs and (3) a preference by the volunteers.

Absorption↗
PubMed1995

Absorption of clonazepam after intranasal and buccal administration.

Serum concentrations of clonazepam after intranasal, buccal and intravenous administration were compared in a cross-over study in seven healthy male volunteers. Each subject received a 1.0 mg dose of clonazepam intranasally and buccally and 0.5 mg intravenously. A Cmax of 6.3 +/- 1.0 ng ml-1 (mean; +/- s.d.) was measured 17.5 min (median) (range 15-20 min) after intranasal administration. A second peak (4.6 +/- 1.3 ng ml-1) caused by oral absorption was seen after 1.7 h (range 0.7-3.0 h). After buccal administration a Cmax of 6.0 +/- 3.0 ng ml-1 was measured after 50 min (range 30-90 min) with a second peak of 6.5 +/- 2.5 ng ml-1 after 3.0 h (range 2.0-4.0 h). Two minutes after i.v. injection of 0.5 mg clonazepam the serum concentration was 27 +/- 18 ng ml-1. It is concluded that intranasal clonazepam is an alternative to buccal administration. However, the Cmax of clonazepam after intranasal administration is not high enough to recommend the intranasal route as an alternative to intravenous injection.

Absorption↗
PubMed1992

Is Recormon less painful than Eprex after subcutaneous administration?

In this study, we examined the differences in pain score after subcutaneous injection of the epoetin preparations Eprex and Recormon. Patients (n = 30) received 5 injections Eprex and 5 injections Recormon in a randomized double-blind sequence. 10 Min after receiving the injection the patient was asked to complete a visual and a verbal analogue scale and two descriptive scales. The results of 25 patients were used for statistical evaluation. The overall results indicate that there are significantly more patients reporting pain after subcutaneous injection of Eprex than after Recormon (11 versus 2 patients, p less than 0.05; McNemar test). 12 Patients reported no differences in pain. 43 Out of 123 injections Eprex and 69 out of 125 injections Recormon caused no pain (p less than 0.01; chi 2 9.455). For 4 patients Recormon was significantly (p less than 0.05) less painful than Eprex. It can be concluded that Recormon may be a less painful alternative for individual patients reporting pain after subcutaneous injection of Eprex.

Adult↗
PubMed1991

Ofloxacin intravenous. Compatibility with other antibacterial agents.

The physical and chemical compatibility of ofloxacin (infusion solution 100 ml = 200 mg) with amoxicillin, amoxicillin + clavulanic acid, flucloxacillin, tobramycin, gentamicin, clindamycin, vancomycin, ceftazidime and piperacillin was investigated. Upon admixture with flucloxacillin a precipitate formed between 7 and 24 hours. No other physical or chemical incompatibilities were observed with any of the other combinations. Ofloxacin may be safely combined with the tested antimicrobial drugs, except for flucloxacillin.

Anti-Bacterial Agents↗
PubMed1990

Comparison of clonazepam sorption to polyvinyl chloride-coated and polyethylene-coated tubings.

The sorption of clonazepam to polyvinyl chloride tubing, polyethylene-coated tubing and to a polyethylene syringe was determined. Pumping of clonazepam (5 mg/48 ml) through the polyvinyl chloride tubing with flow rates of 2 ml/h and 4 ml/h resulted in a reduction of the clonazepam concentration to about 40% and 55% of the original strength after 0.6 h, respectively. This value was 55% at a flow rate of 2 ml/h and a clonazepam concentration of 10 mg/48 ml. The effluent clonazepam concentration increased gradually after an infusion period of 1 h. Sorption of clonazepam to the polyethylene syringe and to the tubing coated on the inside with polyethylene does not occur. The use of polyethylene-coated administration sets is recommended for intravenous administration of clonazepam.

Adsorption↗
PubMed1990

Stability of amphotericin B in CAPD fluid.

Amphotericin B is the drug of choice in continuous ambulatory peritoneal dialysis (CAPD) associated fungal peritonitis and is usually administered intraperitoneally. The drug is stated to be incompatible with anions. All CAPD fluids contain chloride and lactate anions. Therefore, the physical and chemical compatibility of amphotericin B with dextrose 5%, Dianeal 1.36% CAPD fluid, and Dianeal 1.36% peritoneal effluent was studied at amphotericin B concentrations of 1, 2, and 5 mg/L. Amphotericin B was most stable in Dianeal CAPD fluid. The rate of degradation was concentration dependent in dextrose 5% and peritoneal effluent. The higher the concentration, the lower the rate of degradation. After an incubation of 6 h at 37 degrees C, no significant decomposition was found at all concentrations studied in Dianeal CAPD fluid whereas 12-18% decomposition was found in effluent. No physical incompatibility with any solution was observed.

Amphotericin B↗
PubMed1987

Plasma protein binding of digitoxin and some other drugs in renal disease.

Plasma protein binding of most acidic drugs is decreased in uraemia, whereas the binding of basic drugs is usually unchanged or decreased. Decreased protein binding in patients with renal disease mainly relates to drugs binding to albumin. Digitoxin binds to a specific site on the albumin molecule. Conflicting reports exist on digitoxin-protein binding in patients with renal disease. In ten patients with end-stage renal disease treated with haemodialysis we found only a slightly increased free fraction of digitoxin. A heparin-induced increase of the free fraction of digitoxin during haemodialysis has been reported. However, this increase was caused by the generation of non-esterified fatty acids in vitro. If this in vitro lipolysis was blocked, no increase of free digitoxin could be detected. Alterations of digitoxin-protein binding in uraemic patients during haemodialysis and during the intervals between haemodialysis treatments are small.

Blood Proteins↗
PubMed1985

Effect of heparin on digitoxin protein binding.

Reduction of digitoxin binding to plasma proteins after heparin has been reported. Our aim was to determine whether this reduction is an in vivo effect or occurs only after blood collection as a result of heparin-induced lipolysis that increases levels of nonesterified fatty acids in vitro. The effect of heparin on digitoxin protein binding was studied in 10 patients undergoing hemodialysis receiving digitoxin maintenance therapy. Digitoxin free fraction increased after heparin, from 2.5% +/- 0.7% to 4.4% +/- 1.1%, but after inhibition of in vitro lipolysis with diethyl p-nitrophenyl phosphate (2mM), a potent lipase inhibitor, there was no increase in the free fraction (2.3% +/- 0.4% before heparin and 2.4% +/- 0.5% after heparin). Digitoxin salivary levels were also unchanged (0.41 +/- 0.08 ng/ml before heparin and 0.41 +/- 0.08 ng/ml after heparin [n = 8]). These data indicate that the binding of digitoxin to plasma proteins in vivo is not altered by heparin. The reduced binding reported elsewhere was a result of heparin-induced in vitro lipolysis.

Aged↗
PubMed1984

Pitfalls in the determination of unbound carbamazepine concentrations in plasma.

The usefulness of three simple, commercially available ultrafiltration systems [ Centriflo CF25 (A), Centriflo CF50A (B) and Ultrafree (C)] in determining concentrations of unbound carbamazepine in plasma was tested. The concentrations of carbamazepine measured in the first fractions of the ultrafiltrate were low, probably as a result of binding of the drug to the ultrafiltration system. The amount of this binding decreased in the order A greater than B greater than C. When using A and B, the first portion of ultrafiltrate obtained after centrifuging for 15 minutes must therefore be discarded. Using the Ultrafree filters this was not necessary. Plasma proteins were found to pass through the Ultrafree filter membrane when more than 0.7 ml ultrafiltrate was collected. Comparison of the ultrafiltration methods with equilibrium dialysis showed a good correlation: r = 0.96 (A), r = 0.97 (B) and r = 0.98 (C). However, in the carbamazepine plasma concentration range 2.5-10.0 micrograms/ml, significantly lower free fractions were measured with the Centriflo cones. The free fractions measured were: 0.28-0.30 (equilibrium dialysis), 0.17-0.18 (A), 0.22-0.24 (B) and 0.29-0.30 (C). The time required to collect the ultrafiltrate was 30 minutes (A and B) and 2 hours (C).

Carbamazepine↗
PubMed1983

Do evacuated blood collection tubes interfere with therapeutic drug monitoring?

The influence of various brands of evacuated blood collection systems (the old type, red stoppered Vacutainer; the new type, blue stoppered Vacutainer; Monoject and Venoject) on therapeutic drug monitoring was investigated. No interferences were found in the assay of ethosuximide, phenobarbital, phenytoin, valproic acid, digitoxin, digoxin, procainamide, gentamicin and theophylline. Using Monoject and old type Vacutainer tubes, lower levels were found in the disopyramide assay: 91.3 +/- 4.6% (p less than 0.05) and 91.7 +/- 7.0% (not significant) respectively, and in the quinidine assay: 82.8 +/- 6.7% (p less than 0.02) and 83.9 +/- 4.4% (p less than 0.001) respectively as compared with glass tubes. In the carbamazepine assay a decrease was found in the Monoject tubes only: 93.7 +/- 1.7% (p less than 0.01). The stoppers of Monoject tubes and the old type Vacutainer tubes contained the plasticizer tris-(2-butoxyethyl)phosphate (TBEP), which has been shown to be a potent inhibitor of the binding of several drugs to alpha 1-acid glycoprotein. Using the new type Vacutainer and the Venoject, no interferences were found.

Blood Specimen Collection↗
PubMedDate not supplied

Antimicrobial prophylaxis in hysterectomies: a double-blind, randomized, comparative study of a single dose of piperacillin (2 g) versus a single dose of amoxicillin-clavulanic acid (2.2 g).

A double-blind, randomized comparative study of piperacillin (2 g) versus amoxicillin-clavulanic acid (2.2 g) as a single dose 30 minutes before the initiation of hysterectomy was performed. A total of 595 patients (of which 307 were in the piperacillin group) were evaluable for efficacy. Infectious complications were infrequent in both arms. One case of (mild) sepsis was observed in the piperacillin group and two cases of wound infection were observed in the amoxicillin-clavulanic acid group. Urinary tract infection was observed in 5.5% of the patients in the piperacillin group and in 2.4% of the amoxicillin-clavulanic acid group. A relatively high incidence of asymptomatic bacteriuria was seen in both groups: 11.8% in the piperacillin group and 8.7% with amoxicillin-clavulanic acid. A marked difference was seen between the two different hospital locations: a 15% incidence in the hospital where midstream urine was used for culture (Sittard), versus 5% in the hospital where catheter urine was used (Geleen). It is concluded that both antibiotics are associated with a low rate of infectious complications and that catheter urine must be used for sample collection.

Amoxicillin↗