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Drug Interactions between Mytelase Chloride and Quinidex Extentabs

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

quiNIDine ambenonium

Applies to: Quinidex Extentabs (quinidine) and Mytelase Chloride (ambenonium)

GENERALLY AVOID: Anticholinergic agents and other agents with significant anticholinergic activity (e.g., clozapine, class IA antiarrhythmics especially disopyramide) may antagonize the effects of cholinergic skeletal muscle stimulants (e.g., ambenonium, edrophonium, guanidine, neostigmine, pyridostigmine). Although this interaction may be desirable in some situations, such as when atropine is used to treat excessive muscarinic side effects and cholinergic crisis induced by anticholinesterase overdose, unintentional or indiscriminate use of anticholinergic agents in the treatment of myasthenia gravis may exacerbate symptoms. In addition, such use may mask the less serious, gastrointestinal signs of cholinergic overdose and lead to inadvertent induction of cholinergic crisis, which can produce respiratory paralysis and death.

MANAGEMENT: Agents with potent anticholinergic activity should preferably be avoided in patients receiving cholinergic skeletal muscle stimulants. If concurrent use is necessary, patients treated for myasthenia gravis should be monitored for potential exacerbation of symptoms. Caution is advised not only because anticholinergic agents may mask the signs of a cholinergic overdose, but also because increasing muscle weakness associated with disease aggravation may be difficult to distinguish from that due to cholinergic crisis.

References

  1. "Product Information. Mestinon (pyridostigmine)." ICN Pharmaceuticals Inc PROD (2001):

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Drug and food interactions

Moderate

quiNIDine food

Applies to: Quinidex Extentabs (quinidine)

GENERALLY AVOID: In a small, randomized, crossover study, the administration of quinidine with grapefruit juice (compared to water) to healthy volunteers significantly prolonged the time to reach peak plasma quinidine concentrations and decreased the plasma concentrations of its major metabolite, 3-hydroxyquinidine. These changes were associated pharmacodynamically with both a delay and a reduction in the maximal effect on QTc interval. The proposed mechanism is delay of gastric emptying as well as inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits.

MANAGEMENT: Given the drug's narrow therapeutic index, patients receiving quinidine therapy should avoid the consumption of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels.

References

  1. Ace LN, Jaffe JM, Kunka RL "Effect of food and an antacid on quinidine bioavailability." Biopharm Drug Dispos 4 (1983): 183-90
  2. Min DI, Ku YM, Geraets DR, Lee HC "Effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of quinidine in healthy volunteers." J Clin Pharmacol 36 (1996): 469-76
  3. Ha HR, Chen J, Leuenberger PM, Freiburghaus AU, Follah F "In vitro inhibition of midazolam and quinidine metabolism by flavonoids." Eur J Clin Pharmacol 48 (1995): 367-71
  4. Bailey DG, Dresser GR, Kreeft JH, Munoz C, Freeman DJ, Bend JR "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clin Pharmacol Ther 68 (2000): 468-77
View all 4 references

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.


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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.