Yes, it is safe to take Benadryl (diphenhydramine) after abortion pills.
There are no known drug interactions between diphenhydramine and the medication abortion regimen of mifepristone and misoprostol, and diphenhydramine is not listed as a contraindication in current guidelines.
Why This Is Safe
The most recent and comprehensive guidelines on medication abortion 1 detail very few absolute contraindications to mifepristone and misoprostol. The listed contraindications are:
- Allergies to the medications themselves (which are rare)
- Current long-term systemic corticosteroid therapy
- Inherited porphyria
Antihistamines like diphenhydramine are not mentioned as contraindications or problematic medications in any of the guideline evidence provided [@1-9@].
Clinical Context
Diphenhydramine is commonly used for:
- Nausea (which is a known side effect of misoprostol, occurring in approximately 52.6% of patients 2)
- Allergic reactions
- Sleep aid
- Anxiety relief
Since medication abortion is associated with side effects including nausea, vomiting, diarrhea, cramping, and fever 1, using symptomatic relief medications like diphenhydramine is reasonable and does not interfere with the abortion process.
Important Caveats
While diphenhydramine itself is safe to use:
- Monitor for sedation: Diphenhydramine causes drowsiness, which could mask warning signs that require medical attention
- Watch for warning signs regardless: Heavy bleeding, severe pain, fever persisting beyond several hours after stopping misoprostol, or signs of infection still require immediate medical evaluation 1
- Fever differentiation: Misoprostol causes transient fever in 5-10% of patients that resolves within several hours 1. A fever persisting for several hours after misoprostol administration should raise concern for infection and requires evaluation
What Actually Matters After Abortion Pills
The guidelines emphasize monitoring for actual complications 1:
- Retained placenta (most common complication)
- Infection (requires high index of suspicion)
- Hemorrhage (rare, occurring in approximately 0.03% requiring transfusion 3)
Diphenhydramine does not increase the risk of any of these complications and does not interfere with the effectiveness of mifepristone or misoprostol.