Pseudoephedrine drug interactions

As with other sympathomimetic agents, theoretical drug interactions with ephedra alkaloids are possible. Despite this potential, only a handful of adverse drug interactions have been reported. This is especially pertinent when considering the extensive use of both ephedra-containing supplements and ephedrine- or pseudoephedrine-containing OTC products. The most notable interaction exists between nonselective monoamine oxidase inhibitors and ephedra- or ephedrine-containing products. 

It is important to note that pseudoephedrine was used at the recommended dosage drug-drug interactions were unlikely. 

The results prove strong relation between cold contact method data and DSC. The simple eutectic interaction of pseudoephedrine hcl-acetaminophen, the peri-tectic interaction between methampyrone-phenylbutazon, and solid solution formation between amoxicillin trihydrate-clavulanate have been early detected by this simple method. Therefore, this method has high possibility to be used as a simple method to evaluate the other drug interactions [10—13]. 

A technique based on the formation of a multiple emulsion with an external aqueous phase was developed for the encapsulation of water-soluble drugs in order to replace the external oil phase. Possible unwanted interactions between the oil and the emulsified wax such as swelling or dissolution of the wax, clean-up requirements of the final product, and recovery of the oil phase could be eliminated. In analogy to the encapsulation of water-soluble drugs within polymeric microparticles by a w/o/w-solvent evaporation method, a molten wax phase was used instead of an organic polmer solution. A heated aqueous solution of pseudoephedrine HCl was emulsified into the molten carnauba wax, followed by the emulsification of this w/o-emulsion into a heated external aqueous phase. The temperature of the internal and external aqueous phases had to be kept above the melting temperature of the wax in order to avoid premature... 

In 8 healthy subjects a single 150-mg oral dose of phenylpropanolamine decreased the clearance of theophylline (given as a single 4-mg/kg intravenous dose of aminophylline 1 hour after the phenylpropanolamine) by 50%. Such a large reduction in clearance would be expeeted to result in some increase in serum theophylline levels, but so far no studies of this potentially clinically important interaction seem to have been earried out in patients. Be alert for evidence of toxicity if both drugs are used. More study is needed. See also Pseudoephedrine and related drugs + Caffeine , p.1276. 

The interaction between ephedrine or pseudoephedrine and urinary alkalinisers are established but reports of adverse reactions in patients appear to be rare. Be aware that any increase in the adverse effects of these drugs (tremor, anxiety, insomnia, tachycardia, etc.) could be due to drug retention brought about by this interaction. Acetazolamide makes the urine alkaline and would be expected to interact with ephedrine and pseudoephedrine in the same way as sodium bicarbonate. 

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