Propranolol antagonism of phenylpropanolamine-induced hypertension

Synthetic investigation on chirally pure Mannich derivatives of pseudophenylpropanolamine and their anticancer properties against HepG-2 cells with inhibition of JAK2/STAT3

In vitro and in vivo anticancer activity of compound 3a was proved as a novel blocker of JAK2/STAT3 signaling pathway and exerts both anti-proliferative and apoptotic activities in HepG-2 cells with xenograft mice model.

Synthesis of BF₃ catalyzed Mannich derivatives with excellent ee from phenylpropanolamine, study of their antimicrobial activity and molecular docking

Antimicrobial agents 4a-g and 5a-g with very good potency were synthesized with 100% ee from phenylpropanolamine (norephedrine) by BF3 catalyzed three components one pot Mannich reaction in good yields. Obtained compounds were characterized using spectral techniques. Antimicrobial study of these compounds revealed a good to very high potential activity against tested microbes when compared to standard antimicrobial drugs streptomycin and ketoconazole. These synthesized compounds exhibited significant minimum inhibitory concentration (MIC) values against Gram positive and Gram negative bacteria. Amongst compound 4b, 4c, 4d, 4e, 5a, and 5e exhibited very high potent MIC values against tested twelve bacteria and three fungi when compared to control. When subjected to molecular docking, in silico studies revealed significant binding energies ranging from -7.06 to -8.90 kcal/mol for all obtained compounds towards target receptor DNA topoisomerase IV and amongst compounds 4b and 4d have shown maximum binding energies 8.70 and 8.90 kcal/mol, respectively.

Treatment of toxicity from amphetamines, related derivatives, and analogues: a systematic clinical review

BACKGROUND

Overdose of amphetamine, related derivatives, and analogues (ARDA) continues to be a serious worldwide health problem. Patients frequently present to the hospital and require treatment for agitation, psychosis, and hyperadrenegic symptoms leading to pathologic sequelae and mortality.

OBJECTIVE

To review the pharmacologic treatment of agitation, psychosis, and the hyperadrenergic state resulting from ARDA toxicity.

METHODS

MEDLINE, PsycINFO, and the Cochrane Library were searched from inception to September 2014. Articles on pharmacologic treatment of ARDA-induced agitation, psychosis, and hyperadrenergic symptoms were selected. Evidence was graded using Oxford CEBM. Treatment recommendations were compared to current ACCF/AHA guidelines.

RESULTS

The search resulted in 6082 articles with 81 eligible treatment involving 835 human subjects. There were 6 high-quality studies supporting the use of antipsychotics and benzodiazepines for control of agitation and psychosis. There were several case reports detailing the successful use of dexmedetomidine for this indication. There were 9 high-quality studies reporting the overall safety and efficacy of β-blockers for control of hypertension and tachycardia associated with ARDA. There were 3 high-quality studies of calcium channel blockers. There were 2 level I studies of α-blockers and a small number of case reports for nitric oxide-mediated vasodilators.

CONCLUSIONS

High-quality evidence for pharmacologic treatment of overdose from ARDA is limited but can help guide management of acute agitation, psychosis, tachycardia, and hypertension. The use of butyrophenone and later-generation antipsychotics, benzodiazepines, and β-blockers is recommended based on existing evidence. Future randomized prospective trials are needed to evaluate new agents and further define treatment of these patients.

Assessing drug target association using semantic linked data

The rapidly increasing amount of public data in chemistry and biology provides new opportunities for large-scale data mining for drug discovery. Systematic integration of these heterogeneous sets and provision of algorithms to data mine the integrated sets would permit investigation of complex mechanisms of action of drugs. In this work we integrated and annotated data from public datasets relating to drugs, chemical compounds, protein targets, diseases, side effects and pathways, building a semantic linked network consisting of over 290,000 nodes and 720,000 edges. We developed a statistical model to assess the association of drug target pairs based on their relation with other linked objects. Validation experiments demonstrate the model can correctly identify known direct drug target pairs with high precision. Indirect drug target pairs (for example drugs which change gene expression level) are also identified but not as strongly as direct pairs. We further calculated the association scores for 157 drugs from 10 disease areas against 1683 human targets, and measured their similarity using a score matrix. The similarity network indicates that drugs from the same disease area tend to cluster together in ways that are not captured by structural similarity, with several potential new drug pairings being identified. This work thus provides a novel, validated alternative to existing drug target prediction algorithms. The web service is freely available at: http://chem2bio2rdf.org/slap.

Modern drug discovery requires the understanding of chemogenomics, the complex interaction of chemical compounds and drugs with a wide variety of protein target and genes in the body. A large amount of data pertaining to such relationships exists in publicly-accessible datasets but it is siloed and thus impossible to use in an integrated fashion. In this work we have integrated and semantically annotated a large amount of public data from a wide range of databases, including compound-gene, drug-drug, protein-protein, drug-side effects and so on, to create a complex network of interactions relating to compounds and protein targets. We developed a statistical algorithm called Semantic Link Association Prediction (SLAP) for predicting “missing links” in this data network: i.e. compound-target interactions for which there is no experimental data but which are statistically probable given the other relationships that exist in this set. We present validation experiments which show this method works with a high degree of accuracy, and also demonstrate how it can be used to create a drug similarity network to make predictions of new indications for existing drugs.

Urodynamic and haemodynamic effects of a single oral administration of ephedrine or phenylpropanolamine in continent female dogs

This study investigated the effects of a single oral administration of ephedrine (2 mg/kg) or phenylpropanolamine (PPA) (1.5 mg/kg) on the vesico-urethral and cardiovascular functions in continent female dogs. Urethral pressure profilometry (UPP), arterial blood pressures and heart rate were measured in five control dogs and after single-dose treatment with ephedrine or PPA at T(0), T(2h), T(4h), T(6h), T(12h), T(18h) and T(24h). UPPs were performed under propofol anaesthesia and other measurements were performed on awake dogs. A telemetric urodynamic investigation was performed on three additional dogs for 24 h after the administration of each drug. Urethral pressures increased over 4-6 h and urethral functional lengths increased 2-6h after administration of both drugs. During micturition, a decrease in detrusor pressure coupled with an increase in bladder volume was observed after ephedrine administration and there was also an increase in bladder volume after PPA had been given. With both drugs increased arterial blood pressures at 4-6 h were compensated by a decreased heart rate over 12 h. Urethral function was improved after both ephedrine and PPA, and bladder function also improved during micturition following ephedrine.

Cardiac Toxicity From Phenylpropanolamine Overdose in a Dog

A 5-year-old, 29-kg, female Labrador retriever developed tachypnea, tachycardia, and ataxia following ingestion of approximately 48 mg/kg of phenylpropanolamine. Initial diagnostic tests showed multiform ventricular tachycardia, left ventricular dilatation with a focal dyskinetic region in the dorsal interventricular septum, and elevations in creatinine kinase and cardiac troponin I. All abnormalities resolved within 6 months. The transient electrocardiographic, echocardiographic, and biochemical abnormalities were consistent with myocardial necrosis from infarction or direct catecholamine-induced myocardial toxicity.

Myocardial infarction associated with phenylpropanolamine

Phenylpropanolamine is a sympathomimetic agent widely used in over-the-counter and prescription decongestant medications. We describe a young woman without cardiac risk factors who sustained myocardial infarction after unintentional overuse of a nasal decongestant containing phenylpropanolamine. The pathophysiology of myocardial injury and current management strategies as related to this agent are discussed. Although serious adverse reactions to phenylpropanolamine are uncommon, potentially serious harm may be caused by this widely available drug in healthy individuals.

Hyperthermia in psychostimulant overdose

Psychostimulant drugs such as amphetamines, amphetamine derivatives, and cocaine produce a variety of potentially lethal effects, and an understanding of these toxic effects is important for emergency physicians. While some effects of psychostimulant poisonings such as cardiovascular compromise and seizures have been discussed extensively, other metabolic derangements such as hyperthermia are less well characterized. In fact, hyperthermia is a common feature of severe-to-lethal poisonings and may be the primary mode of demise in some patients. Animal studies confirm that drug-induced hyperthermia alone can be lethal in some species, although other toxic effects may predominate at different drug doses or rates of administration. In non-lethal poisonings, hyperthermia can produce rhabdomyolysis, leading to further morbidity. Clinical reports and animal studies indicate that hyperthermia is a primary effect of psychostimulant drugs and can occur independently of seizures or increased motor activity. Furthermore, activation of particular dopamine receptors in the central nervous system appears to mediate psychostimulant-induced hyperthermia. The literature suggests cooling and tranquilization of psychostimulant-poisoned patients after cardiovascular stabilization. Paralysis and mechanical ventilation may be required. The involvement of dopamine receptor activation in psychostimulant toxicity suggests that dopamine-blocking neuroleptic drugs may be a useful adjunct to current treatment regimens. However, further studies are required to assess this approach. In summary, hyperthermia is a potentially lethal but treatable manifestation of severe psychostimulant poisoning.

Intravenous propranolol reverses hypertension after sympathomimetic overdose: two case reports

Hypertension is a potential complication following ephedrine and pseudoephedrine overdoses. Treatment with propranolol, a beta blocker, is not recommended since it may produce be an alpha agonist with the potential for further elevated blood pressure. Two patients who developed hypertension following sympathomimetic overdoses were treated with propranolol. After ingesting 4500 mg of pseudoephedrine, a 24 year-old male developed a blood pressure of 220/108. Five min after intravenous propranolol 1 mg BP was 153/88. After ingesting 17,500 mg of ephedrine a 29 year-old female developed a BP of 168/106. Her BP was 124/90 five min after intravenous propranolol. Further study is needed to investigate the potential therapeutic benefit of propranolol in the treatment of sympathomimetic-induced hypertension.

Dose-dependent response to phenylpropanolamine: inhibition of orthostasis

Phenylpropanolamine, a widely consumed over-the-counter drug, is known to elevate blood pressure, but the mechanism is unknown; it may be both a direct and indirect sympathomimetic. This study investigated the effects of 75-mg sustained-release phenylpropanolamine, 75-mg phenylpropanolamine plus 400-mg caffeine, and 150-mg phenylpropanolamine on blood pressure, plasma norepinephrine, and epinephrine levels in 16 normotensive subjects in a double-blind, placebo-controlled crossover design. Mean peak phenylpropanolamine levels of 317 +/- 26, 152 +/- 17, and 157 +/- 17 ng/mL for 150-mg phenylpropanolamine, 75-mg phenylpropanolamine, and 75-mg phenylpropanolamine plus 400-mg caffeine, respectively, were reached at about 3.6 hours after dosing. The maximal increases in supine diastolic blood pressures after all three phenylpropanolamine-containing drugs were almost three times that after placebo (P less than .05), but peak blood pressures occurred at about 2.3 hours earlier than peak phenylpropanolamine levels. Blood pressure increases correlated with phenylpropanolamine plasma levels (r = .49 for systolic blood pressure and r = .34 for diastolic blood pressure; P less than .0001 for both). Norepinephrine levels increased after the administration of 150-mg phenylpropanolamine and 75-mg phenylpropanolamine plus 400-mg caffeine; norepinephrine increases correlated with phenylpropanolamine levels (r = .34, P less than .0001). The expected increment in norepinephrine induced by standing was significantly decreased by phenylpropanolamine in a dose-dependent mode. The study supports the idea that phenylpropanolamine as both a direct (at alpha -1 and alpha-2 receptors) and an indirect sympathomimetic agent.

Adverse drug effects attributed to phenylpropanolamine: a review of 142 case reports

Phenylpropanolamine (PPA) is contained in about 106 products, over half of which are available over-the-counter (OTC). Most are cough/cold remedies; nine are OTC diet aids. More than nine million Americans were using OTC diet aids in 1981, making PPA the fifth most used drug in the United States, responsible for over $200 million in revenues. The safety of PPA remains controversial. Although most controlled studies indicate minimal pressor effects with recommended doses, adverse drug reactions (ADRs) continue to be documented. Since 1965, 142 ADRs have been reported in 85 studies, 69% of these in North America. Many such cases may go unrecognized. About two thirds of all ADRs occurred in females and in patients under 30. Of ADRs attributed to legitimately sold PPA products, 85% occurred after consumption of OTC products versus only 15% after prescription drugs. The PPA product often contained combination ingredients, or PPA was consumed along with additional drugs. An overdose of PPA was taken in about a third of the cases. After ingestion of non-overdose amounts, 82% of the ADRs were severe. The most frequent side effects involved symptoms compatible with acute hypertension, with severe headache the most common complaint. Twenty-four intracranial hemorrhages, eight seizures, and eight deaths (most due to stroke) were associated with PPA ingestion. We have summarized these data in an effort to alert clinicians to the prevalence of usage of PPA products and the potential for adverse effects. In patients who present with elevated blood pressure or signs of acute hypertension, especially hypertensive encephalopathy of undetermined origin, we recommend inquiry about recent ingestion of PPA-containing diet aids and cough/cold products and suggest having such patients remain upright rather than supine.

Drug interactions in hypertensive patients. Pharmacokinetic, pharmacodynamic and genetic considerations

Antihypertensive treatment has proven benefits, and the number of patients being treated with these drugs is significant. Hypertensive patients may have other medical illnesses for which they receive medications, and interactions between antihypertensive agents and other drugs is likely. Some of these interactions may lead to undesirable effects or even loss of blood pressure control. However, drug interactions can also be beneficial when 2 antihypertensive drugs with different pharmacological actions are prescribed in combination and with a clear therapeutic objective in mind. Clinicians should be aware of the mechanisms and the consequences of the different types of interaction in hypertensive patients, so that a desired pharmacological response can be achieved with the fewest side effects in the patients.

Transient hypertension after two phenylpropanolamine diet aids and the effects of caffeine: a placebo-controlled follow-up study

PURPOSE AND PATIENTS AND METHODS

Reports of severe adverse reactions following the ingestion of single (75 mg) or double doses of the sympathomimetic drug phenylpropanolamine (PPA), with and without caffeine, prompted us to undertake a study of the effects of five drug preparations (75 mg PPA, 150 mg PPA, 75 mg PPA plus 400 mg caffeine, 400 mg caffeine, and placebo) in 16 resting, normotensive subjects. The study was of a double-blind, randomized, crossover design. Each subject consented to take the five drug preparations on different study days, which were separated by at least 48 hours.

RESULTS

Compared with blood pressure (BP) values obtained after placebo ingestion, significant BP increases occurred over several hours following 150 mg PPA and after 75 mg PPA plus 400 mg caffeine. Significant BP increases after ingestion of 75 mg PPA and after 400 mg caffeine were less frequent. The mean peak BP following 150 mg PPA was 173 +/- 9/103 +/- 4 mm Hg, compared with 148 +/- 4/97 +/- 3 mm Hg after the other three active preparations; after placebo, peak BP reached 137 +/- 8/85 +/- 5 mm Hg.

CONCLUSION

These results indicate that 150 mg PPA (the amount in two diet aids) substantially elevates BP. Our findings may explain some of the recent case reports of nontraumatic intracranial hemorrhage in young, healthy persons ingesting PPA at recommended or minimally greater dosages. We suggest physicians inform patients who are likely consumers of PPA (i.e., those with allergies, those with eating disorders, overweight persons, women during the postpartum period) and patients at risk for stroke (i.e., the elderly and hypertensive patients) of the risks of taking more than the recommended amounts of PPA and of combining caffeine with PPA.

Beta 2-adrenoceptor influences on the alpha 1- and alpha 2-mediated vasoconstriction induced by phenylpropanolamine and its two component enantiomers in the pithed rat

Phenylpropanolamine (PPA, (+/-)-norephedrine) is commonly found in appetite suppressants and nasal decongestants. Within the cardiovascular system of the pithed rat, the drug and its two component enantiomers ((-)- and (+)-norephedrine) are largely direct-acting agonists. The interaction between simultaneous alpha 1-, alpha 2- and beta 2-adrenoceptor mediated effects of the drug and its two enantiomers have been examined using the cardiovascular system of the pithed rat. On all adrenoceptors tested the potency was (-)- greater than (+/-)-, greater than (+)-norphedrine. The alpha 1- and alpha 2-mediated pressor responses of each were enhanced in the presence of the beta 2-adrenoceptor antagonist, ICI 118,551, and diminished in the presence of the selective beta 2-adrenoceptor agonist salbutamol. It is concluded that each form of the drug possesses the intrinsic ability to interact with the alpha 1-, alpha 2- and beta 2-adrenoceptors in the system used and that the interaction with those adrenoceptors determines the net increase in diastolic blood pressure that follows the intravenous administration of the compounds. These findings have a bearing on the recent controversy regarding the use of beta-blocking agents in the treatment of overdosage of the drug.

Non-prescription sympathomimetic agents and hypertension

In recent years, considerable attention has been focused on the pressor effects of nonprescription sympathomimetic agents. The impact and usage of these agents especially ephedrine, pseudoephedrine, phenylpropanolamine and phenylephrine, in hypertensive patients has been the topic of constant debates. The present review is an attempt to report and evaluate all the clinical trials and cases of pressor reactions associated with these 4 agents. The study protocols used in these clinical trials are examined and comments made on any diversion from the standard design. Many factors are found to cause the discrepancies in the data available. It is concluded that ephedrine and phenylpropanolamine are best avoided by hypertensive patients due to higher probability of causing pressor reactions. Data on pseudoephedrine and phenylephrine appear to indicate non-significant effects on blood pressure of normotensive subjects when used at the recommended oral dose as nasal decongestants. Phenylephrine is also commonly employed in nasal and eye drops and the limited data available appear to support its usage in hypertensive patients. However, it is noted that most of the clinical trials involve normotensive subjects and the majority of the results could not be verified due to inadequacies in the study design. This paucity and inconclusive information on hypertensive patients warrants further investigations with emphasis on the study protocols used.

A double dose of phenylpropanolamine causes transient hypertension

PURPOSE

Phenylpropanolamine is widely used and freely available without a doctor's prescription in drug and grocery stores; it is the active ingredient in most diet aids and many cold preparations. Several cases of multiple cerebral hemorrhages associated with transient hypertension have recently been attributed to phenylpropanolamine in dosages equal to or less than that contained in two diet aids (i.e., 150 mg). Some evidence also exists on the additive effects of the co-ingestion of phenylpropanolamine and caffeine. We therefore undertook a study to demonstrate that a significant health risk can be caused by a double dose of a typical over-the-counter (OTC) diet aid (i.e., 150 mg phenylpropanolamine) and also when 75 mg phenylpropanolamine is taken with caffeine.

SUBJECTS AND METHODS

Five men and one woman, ranging in age from 20 to 30, participated in this study. The drug preparations were administered to each subject on different study days in a double-blind, randomized-crossover design. Identical capsules contained 75 mg sustained-release phenylpropanolamine, 400 mg of sustained-release caffeine, or placebo. Subjects ingested three capsules at the beginning of each study day. For 150 mg, two phenylpropanolamine-containing capsules and one placebo were taken; for 75 mg, one phenylpropanolamine capsule and two placebos; and for phenylpropanolamine plus caffeine, one 75 mg phenylpropanolamine capsule, one 400 mg caffeine capsule, and one placebo. Blood pressure and heart rate were monitored throughout the study.

RESULTS

Although 75 mg of phenylpropanolamine did not cause clinically relevant hypertension in our subjects, 150 mg of phenylpropanolamine and 75 mg of phenylpropanolamine plus 400 mg caffeine did result in significant blood pressure increases into the hypertensive range.

CONCLUSION

We believe that consumers often assume that double the recommended dosage of an OTC drug is safe and more effective. We suggest that requiring a physician's prescription or an additional, stronger warning label on phenylpropanolamine-containing products may prevent substantial mortality and morbidity.

Phenylpropanolamine and other over-the-counter vasoactive compounds

Phenylpropanolamine is a sympathomimetic amine that shares structural similarities with amphetamine and ephedrine. It increases blood pressure primarily by increasing peripheral vascular resistance. This effect is the result of alpha-adrenergic agonist activity largely from both direct stimulation of adrenergic receptors and release of neuronal norepinephrine. As such, it has the potential to interact with other drugs to produce toxic reactions, especially in treated hypertensive patients. Complications have occurred with single oral doses that suggest some normal subjects may be more sensitive to the drug than others. The incidence of serious complications in the general population is small but could be much higher in susceptible individuals (e.g., cardiomyopathic and hypertensive patients). The availability of high-dose phenylpropanolamine-containing preparations without medical supervision is potentially dangerous, and certain restrictions should be imposed on such preparations.

Nonpharmacologic therapy of hypertension

At least seven nondrug therapies have been shown to reduce the blood pressure in some hypertensive patients. Although each has its detractors, I believe most should be utilized in the therapy of most hypertensives. Some, such as weight reduction for the obese, decreased saturated fat intake, regular isotonic exercise, and moderation of alcohol, can be enthusiastically advocated for everyone, since they may accomplish additional improvements in overall cardiovascular risk beyond their effect on blood pressure. Others such as moderate sodium restriction, adequate dietary sources of potassium, magnesium, and calcium, and relaxation therapy, can be helpful in at least some hypertensives and should be appropriately applied to the therapy of those who may benefit. To varying degrees, nondrug therapies should be included in the treatment of all patients with hypertension.

Adrenergic receptor subtype activation by (+)-, (-)- and (+/-)-norephedrine in the pithed rat

The ability of (+/-)-norephedrine (phenylpropanolamine) and its component isomers, (+)-and (-)-norephedrine, to activate adrenergic receptor subtypes in the cardiovascular system of the urethane/chloralose-anaesthetized pithed rat has been investigated. At all adrenoceptor subtypes, (-)-norephedrine was the most potent agonist followed by (+/-)- then (+)-norephedrine. The greatest activity was observed at the alpha 1-receptor, with little activity observed at either beta 1 or beta 2-adrenoceptors. Reserpinization shifted the (-)-norephedrine dose-response curve slightly to the right, indicating that only a minor portion of its activity is due to the release of stored endogenous catecholamines. These results suggest that most of the cardiovascular activity of the compounds is through the direct activation of alpha 1-adrenoceptors.