Do anticholinergics like diphenhydramine (Benadryl) or dicyclomine decrease immune function?

As a general group, they do not. Rather, some of them (but not all) tend to block histamine. However, they are called anti-cholinergic because they block the neurotransmitter succinylcholine, and therefore increase heart rate and blood pressure, cause dry mouth, constipation, urinary retention, bowel obstruction, dilated pupils, blurred vision, increased heart rate, and decreased sweating, among other things.

Diphenhydramine ARE immune suppresants!

What Are Side Effects Associated with Using Dicyclomine?

Side effects associated with use of Dicyclomine, include the following:

Dizziness

Dry mouth

Blurred vision

Drowsiness

Nervousness

Weakness

Other side effects of dicyclomine include:

Bloating

Confusion

Cycloplegia

Delirium

Dermatitis

Fainting or lightheadedness

Fatigue

Feeling unwell (malaise)

Hallucinations

Insomnia

Palpitations

Rash

Redness

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

No they don’t particularly