Pyrilamine Drug Interactions: What to Avoid and What to Tell Your Doctor

Pyrilamine interacts with a large number of medications. According to Drugs.com's interaction database, there are over 423 known drug interactions with pyrilamine — 11 classified as major, 410 as moderate, and 2 as minor. This guide focuses on the most clinically important interactions you need to know before starting pyrilamine.

The Most Dangerous Interaction: MAOIs

The single most important drug interaction with pyrilamine is with monoamine oxidase inhibitors (MAOIs). This combination is contraindicated.

MAOIs include:

• Phenelzine (Nardil)
• Tranylcypromine (Parnate)
• Isocarboxazid (Marplan)
• Selegiline (Eldepryl, Emsam — Parkinson's/depression)

MAOIs prolong and intensify pyrilamine's anticholinergic effects, potentially leading to dangerous CNS toxicity. You must not take pyrilamine if you are currently taking an MAOI, or within 14 days of stopping an MAOI. If you're not sure whether your antidepressant is an MAOI, ask your pharmacist before taking any pyrilamine product.

Major Interaction: CNS Depressants (Including Alcohol)

Pyrilamine causes significant CNS sedation on its own. When combined with other CNS depressants, the effects are additive and can become dangerous. Substances to avoid include:

• Alcohol — significantly potentiates pyrilamine's sedative effect; dangerous levels of CNS depression possible
• Opioids (codeine, hydrocodone, oxycodone, morphine) — additive respiratory depression risk
• Benzodiazepines (alprazolam/Xanax, diazepam/Valium, lorazepam/Ativan) — increased sedation and CNS depression
• Barbiturates — increased CNS and respiratory depression
• Sleep aids (zolpidem/Ambien, eszopiclone/Lunesta) — additive sedation, impaired coordination
• Muscle relaxants (cyclobenzaprine/Flexeril, carisoprodol/Soma) — increased sedation

Moderate Interaction: Anticholinergic Drugs

Although pyrilamine has low anticholinergic activity itself, combining it with other drugs that have anticholinergic properties can add up:

• Tricyclic antidepressants (amitriptyline/Elavil, nortriptyline) — increased risk of delirium, hyperthermia, urinary retention
• Bladder medications (oxybutynin/Ditropan, solifenacin/VESIcare) — increased anticholinergic burden
• Antiparkinsonian drugs (benztropine/Cogentin, trihexyphenidyl) — additive anticholinergic effects

Moderate Interaction: Warfarin

If you are taking warfarin (Coumadin) for blood thinning, be cautious with pyrilamine combination products. Midol Complete, for example, contains acetaminophen — which can potentiate warfarin's anticoagulant effect when taken regularly. Monitor INR and inform your prescriber if you take these products more than occasionally.

Special Concern: Ototoxic Medications

Pyrilamine may mask the early symptoms of ototoxicity (hearing damage or dizziness) caused by aminoglycoside antibiotics such as gentamicin or tobramycin. If you are receiving IV antibiotics of this type, inform your care team if you are also taking any pyrilamine product.

What to Tell Your Doctor and Pharmacist

Before taking pyrilamine, inform your healthcare provider about:

• All current medications — prescription, OTC, and supplements
• Current or recent MAOI use (within the past 2 weeks)
• Use of any CNS depressants, sleep aids, or anti-anxiety medications
• Warfarin or other blood thinners
• Any history of glaucoma, prostate conditions, or asthma
• Pregnancy or breastfeeding status

Summary Table of Key Interactions

CONTRAINDICATED (Avoid completely):

• MAOIs (phenelzine, tranylcypromine, isocarboxazid, selegiline)

MAJOR (Use with extreme caution or avoid):

• Alcohol, opioids, benzodiazepines, barbiturates, other sedatives

MODERATE (Use with caution; inform your provider):

• Tricyclic antidepressants, anticholinergics, warfarin, aminoglycosides

Also see our full guide to pyrilamine side effects for more safety information.