epinephrine vs promethazine

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Side-by-side comparison of epinephrine and promethazine. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

minor Known Drug Interaction

Epinephrine - Because of the potential for promethazine HCl to reverse epinephrine's vasopressor effect, epinephrine should NOT be used to treat hypotension associated with Promethazine HCl Suppositories overdose.

Drug Class
epinephrine Adrenergic Agonist
promethazine Phenothiazine Antiemetic / Antihistamine
Type
epinephrine Prescription
promethazine Prescription
Summary
epinephrine

Epinephrine injection is a medicine that raises blood pressure. It is used for adults with very low blood pressure due to septic shock.

promethazine

Promethazine suppositories are a medicine that can help with allergies, motion sickness, nausea, vomiting, and sleep problems. It works by blocking certain natural substances in your body.

What It Treats
epinephrine

Epinephrine injection is used to increase blood pressure in adults. It is specifically for those who have low blood pressure because of septic shock. Septic shock is a severe condition caused by infection.

promethazine

This medicine can treat allergy symptoms like a runny nose or itchy eyes. It can also help prevent motion sickness. Promethazine can also be used to control nausea and vomiting, especially after surgery. Sometimes, it's used to help you relax or sleep before or after surgery.

How It Works
epinephrine

Epinephrine works on alpha and beta receptors in your body. This causes your blood vessels to narrow and your heart to beat stronger and faster. As a result, your blood pressure increases.

promethazine

Promethazine belongs to a class of drugs called antihistamines and antiemetics. It works by blocking histamine, a substance in the body that causes allergic symptoms. It also affects the part of the brain that controls nausea and vomiting.

Common Side Effects
epinephrine
  • Headache
  • Anxiety
  • Feeling restless
  • Shaking
  • Weakness
promethazine
  • Drowsiness
  • Dry mouth
  • Blurred vision
  • Dizziness
FAERS Reports
epinephrine
  • Headache 4,161
  • Sinusitis 3,917
  • Fatigue 3,761
  • Dyspnoea 3,215
  • Pain 3,151
promethazine
  • Nausea 2,530
  • Vomiting 1,734
  • Pain 1,453
  • Fatigue 1,408
  • Diarrhoea 1,271
Serious Warnings
epinephrine

Your blood pressure will be checked often while you are taking this medicine. Epinephrine can raise your blood pressure too high. It can also cause fluid to build up in your lungs. Epinephrine may cause irregular heartbeats or reduce blood flow to the heart. Avoid leakage of the medicine into the tissues, as this can cause tissue damage. This medicine contains sulfite, which can cause allergic reactions.

promethazine

Promethazine suppositories should not be used in children under 2 years old because it can cause serious breathing problems, which can be fatal. Use with caution in children 2 years and older, and use the lowest effective dose. Avoid giving this medicine with other drugs that can also cause breathing problems.

Pregnancy
epinephrine

Epinephrine may harm your unborn baby. Tell your doctor if you are pregnant or plan to become pregnant. Epinephrine can also slow down labor.

promethazine

Tell your doctor if you are pregnant or breastfeeding before using this medicine. It is not known if promethazine can harm an unborn baby or pass into breast milk.

How to Read This epinephrine vs promethazine Comparison

epinephrine is classified in the Adrenergic Agonist drug class, while promethazine sits within the Phenothiazine Antiemetic / Antihistamine class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, epinephrine has 18,205 submissions while promethazine has 8,396. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to promethazine can block the way epinephrine normally raises blood pressure, which might cause blood pressure to drop even lower.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for epinephrine or promethazine.

Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.