An open-label, randomized, four-treatment crossover study evaluating the effects of salt form, acetaminophen, and food on the pharmacokinetics of phenylephrine.

Phenylephrine hydrochloride (HCl) is a decongestant available in over-the-counter (OTC) medicines. Previously marketed prescription products contained phenylephrine tannate, an extended-release salt, which allowed dosing every 8-12 h. Given the regulatory history that cold medicines marketed before 1962 had limited supporting clinical data, and with widespread replacement of pseudoephedrine by phenylephrine in OTC products over the last ten years, the need for contemporary studies grew. This exploratory crossover study evaluated effects of salt form, acetaminophen, and food on phenylephrine pharmacokinetics and metabolites in healthy adults. Test treatments were 25 mg phenylephrine tannate (equivalent to 10 mg phenylephrine HCl) combined with 200 mg guaifenesin, fasted; 10 mg phenylephrine HCl combined with 650 mg acetaminophen, fasted; and 10 mg phenylephrine HCl, fed. The reference treatment was 10 mg phenylephrine HCl, fasted. Plasma phenylephrine pharmacokinetics and urine metabolites were determined. Although the tannate salt slowed phenylephrine absorption compared with the HCl salt, terminal concentrations were similar, suggesting that products containing the tannate salt should not be dosed less frequently than those containing the HCl salt. The premise that acetaminophen increases phenylephrine bioavailability by competition for presystemic sulfation was corroborated by increased phenylephrine sulfate in urine. Food delayed phenylephrine absorption, but not the total amount absorbed.

Xylometazoline poisoning: A 40-fold nasal overdose caused by a compounding error in 3 children.

The imidazoline derivative xylometazoline, an alpha-2-adrenergic agonist, is used as non-prescription nasal preparation due to its vasoconstrictive and decongestive properties. Especially in children, an overdose can quickly cause severe central nervous system depression and cardiovascular adverse effects. In three 3-year-old boys (triplets) a xylometazoline intoxication was diagnosed by toxicological analysis. On admission to an emergency unit all three children were still unresponsive. One triplet showed respiration of 15-20 breaths/min and required oxygen support (3L/min) via face mask; his electrocardiogram revealed sinus bradycardia of 64 beats/min with supraventricular extrasystoles. However, no interventions were necessary except fluid management via intravenous lines. Eleven hours after the event, two of the triplets were awake but still not fully oriented. The third triplet woke up 20h after instillation of nose drops. Intoxication was caused by a compounding error in a pharmacy resulting in a concentration 40 times above the adequate dosage for children. In general, physicians, pharmacists and the public should be educated about the toxicity of over-the-counter preparations.

Evaluation of the 20% D-methamphetamine requirement for determining illicit use of methamphetamine in urine.

In urine drug testing, enantiomer analysis is used to determine whether a positive methamphetamine result could be due to use of an over-the-counter (OTC) nasal inhaler containing L-methamphetamine. D-methamphetamine at more than 20% of the total is considered indicative of a source other than an OTC product. This interpretation is based on a 1991 Department of Health and Human Services (HHS) Technical Advisory. We performed studies to verify the methamphetamine enantiomer content of current OTC nasal inhalers and to evaluate current laboratory testing capabilities. This study demonstrated that OTC inhalers contain less than 1% D-methamphetamine. A proficiency testing (PT) set for HHS-certified laboratories performing methamphetamine enantiomer testing found D-methamphetamine percentages that were consistently 1 to 3% higher than theoretical due to optical impurity of the derivatizing reagent N-trifluoroacetyl-L-prolyl chloride (L-TPC). The PT results also demonstrate that laboratories can accurately determine 20% D-methamphetamine in samples with total methamphetamine concentrations down to 250 ng/mL. Based on these studies, the guideline of >20% D-methamphetamine is appropriate for interpreting results obtained using current laboratory methods.

Determination of tuaminoheptane in doping control urine samples.

Since January 2007, the list of prohibited substances established by the World Anti-Doping Agency includes the sympathomimetic compound tuaminoheptane (1-methyl-hexylamine, 2-heptylamine). Primarily used as nasal decongestant drug it has been considered relevant for sports drug testing due to its stimulating properties. A confirmatory gas chromatographic-mass spectrometric procedure was developed including liquid-liquid extraction and imine formation of tuaminoheptane employing various aldehydes and ketones such as formaldehyde, acetaldehyde, benzaldehyde and acetone. Extraction and derivatisation conditions were optimised for utmost efficiency, and characteristic fragment ions obtained after electron ionisation allowed for a sensitive and selective analytical assay, which was validated with regard to recovery (50%), lower limit of detection (20 ng mL(-1)) as well as interday- and intraday precision (<15%). The applicability to authentic urine samples was demonstrated using administration study specimens obtained from two male persons using Rhinofluimucil (tuaminoheptane hemisulfate) for intranasal application. The administered drug was detected up to 46 h after repeated topical instillation of a total of approximately 3 mg.

Elimination of ephedrines in urine following multiple dosing: the consequences for athletes, in relation to doping control.

AIMS: To study the elimination of ephedrines with reference to the International Olympic Committee (IOC) doping control cut-off levels, following multiple dosing of over-the-counter decongestant preparations. METHODS: A double-blind study was performed in which 16 healthy male volunteers were administered either pseudoephedrine or phenylpropanolamine in maximal recommended therapeutic doses over a 36-h period. Urine was collected every two hours between 08:00 and 24:00 h and at 04:00 h throughout the testing period of three days. Urine drug levels were quantified using high performance liquid chromatography. Side-effects were assessed, including heart rate and blood pressure, every four hours between 08:00 and 20:00 h. RESULTS: Mean (95% CI) total phenylpropanolamine and pseudoephedrine eliminated unchanged was 75 (88, 61) and 81 (92, 71)%, respectively. Maximum urine concentrations of phenylpropanolamine and pseudoephedrine were 112.1 (164.2, 59.9) and 148.5 (215.0, 82.1) mg.l(-1), respectively. A peak in drug urine concentration occurred four hours following the final dose. There were no adverse cardiovascular effects and only mild CNS stimulation was evident. CONCLUSIONS: Following therapeutic, multiple dosing, drug levels remain above the IOC cut-off levels for a minimum of 6 h and 16 h following final doses of phenylpropanolamine and pseudoephedrine, respectively. Athletes require informed advice on this from their healthcare professionals.

Naphazoline intoxication in a child-a clinical and forensic toxicological case.

The imidazoline derivative naphazoline, an alpha(2)-adrenergic agonist, is used as non-prescription eye and nasal preparation because of its vasoconstrictive and decongestive properties. Especially in children, overdose and/or systemic side effects due to absorption can quickly cause severe central nervous system depression and cardiovascular adverse effects. In a 7-year-old boy was diagnosed a naphazoline intoxication by toxicological analysis. The case was also of forensic interest, because the naphazoline mixture was prepared in a pharmacy in a concentration 80 times above the adequate dosage for children. In general, physicians, pharmacists and the public should be educated about the toxicity of over-the-counter preparations.