Mixing Diphenhydramine (Benadryl) and Methylphenidate (Ritalin)

Caution

Amphetamines can hide how confused diphenhydramine is making you, and together they strain the heart.

Do this

Keep diphenhydramine to ordinary medical doses.

General answer for Amphetamines: nothing specific to these two is documented.

Where the risk isTap for why
What “Caution” means

Carries risk that is worth understanding before combining. Reduce doses and do not use alone.

How the ratings work
The longer explanation

Amphetamines as a stimulant may mask some of the negative side effects of DPH, leading to delusions of sobriety which has additional concern in states of delirium. The combination of stimulants will increase strain on the heart and may cause some physical discomfort, and has the chance to cause life-threatening cardiovascular issues. The combination may also increase each other's neurotoxicity at higher dosages. The combination may increase anxiety levels and risks of thought loops on higher dosages, in addition to increasing each others negative side effects. Medical and common dosages of each substances are reported to not be a concern. Additionally, it is suggested that DPH potentiates amphetamine psychomotor activation, in addition to other interactions such as potentiation through inhibition of CYP2D6 and histamine H1 and H2 receptors, among other alterations.

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Other names
Diphenhydramine
benadryl, dph, sleep aid, zzzquil, unisom, doxylamine
Methylphenidate
ritalin, ritalin la, concerta, focalin, dexmethylphenidate, methylin
Not an amphetamine, but mixes much like one — most answers here are Adderall's
Also searched asBenadryl and Ritalin, dph and Ritalin, Benadryl and ritalin la, dph and ritalin la
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Related combinations

Diphenhydramine withWhat not to mix with Diphenhydramine →
Methylphenidate withWhat not to mix with Methylphenidate →
All combinations →

Can you mix Diphenhydramine (Benadryl) and Methylphenidate (Ritalin)?

MixSafe rates mixing Diphenhydramine and Methylphenidate as "Caution" — carries risk that is worth understanding before combining. Reduce doses and do not use alone. No interaction specific to Diphenhydramine and Methylphenidate is documented; this is the default for Amphetamines. Source: TripSit drug combination chart, retrieved 2026-08-20. Educational information, not medical advice.

This is a class-level answer, inherited from Amphetamines. Nothing specific to this exact pair is documented, so treat it as the default for the class rather than a measurement of these two drugs together.