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Promethazine-Phenylephrine

Drug Information

Common brand names:

Phenergan VC

Summary of Interactions with Vitamins, Herbs, & Foods

What Are Nutrient Interactions
Types of interactions:BeneficialAdverseCheck

Replenish Depleted Nutrients

  • none

Reduce Side Effects

  • none

Support Medicine

  • none

Reduces Effectiveness

  • none

Potential Negative Interaction

  • Antihistamines, including promethazine, can cause “anticholinergic” side effects such as dryness of mouth and heart palpitations. Henbane also has anticholinergic activity and side effects. Therefore, use with promethazine could increase the risk of anticholinergic side effects, though apparently no interactions have yet been reported with promethazine and henbane. Henbane should not be taken except by prescription from a physician trained in its use, as it is extremely toxic.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.

Explanation Required

  • Fo-Ti

    Many drugs used in the treatment of high blood pressure cause relaxation or dilation of blood vessels. Laboratory studies show that emodin, a compound in Polygonum multiflorum, also relaxes blood vessels. However, animal studies reveal that phenylephrine blocks the action of emodin. Controlled studies are needed to determine whether Polygonum multiflorum helps people with high blood pressure and whether phenylephrine blocks its beneficial effects.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.

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