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

Cobenfy (xanomeline and trospium chloride) can interact with other medications, supplements, and substances. Because Cobenfy contains two active components — xanomeline (a muscarinic agonist) and trospium chloride (a muscarinic antagonist) — it has interactions related to both components. This guide explains the most important interactions and what you need to share with your healthcare team.

Important: This guide is for educational purposes only. Always review your full medication list with your prescribing doctor and pharmacist before starting Cobenfy.

Category 1: Other Anticholinergic (Antimuscarinic) Drugs

Cobenfy contains trospium chloride, which is an antimuscarinic drug. If you take other antimuscarinic medications at the same time, the combined effect can increase the frequency and severity of anticholinergic side effects such as constipation, dry mouth, urinary retention, and blurred vision.

Common antimuscarinic drugs to be aware of include:

• Overactive bladder medications: oxybutynin (Ditropan), tolterodine (Detrol), solifenacin (VESIcare), darifenacin (Enablex)
• Antihistamines with anticholinergic effects: diphenhydramine (Benadryl), hydroxyzine (Vistaril)
• Certain antidepressants: tricyclic antidepressants (amitriptyline, nortriptyline, imipramine)
• Stomach/bowel medications: dicyclomine (Bentyl), hyoscyamine (Levsin)

Category 2: Strong CYP2D6 Inhibitors

Some medications inhibit a liver enzyme called CYP2D6, which is involved in how your body processes some drugs. Taking strong CYP2D6 inhibitors with Cobenfy may increase the blood levels of xanomeline, increasing the risk of Cobenfy-related side effects. Tell your doctor if you take:

• Fluoxetine (Prozac)
• Paroxetine (Paxil)
• Bupropion (Wellbutrin)
• Quinidine

Category 3: Drugs That Affect Kidney Elimination

Trospium chloride (the second component of Cobenfy) is eliminated from the body mainly through the kidneys via a process called active tubular secretion. Drugs that are eliminated by the same pathway can compete with trospium, leading to higher blood levels of both drugs and more side effects. Ask your doctor about this if you take medications for gout, infections, or other conditions that may use the same kidney pathway.

Category 4: Sensitive CYP3A4 or P-glycoprotein Substrates

Cobenfy may affect how your body processes drugs that are sensitive substrates of the CYP3A4 enzyme or P-glycoprotein transporter. This could increase the blood levels and potential side effects of those other medications. Your doctor should review any sensitive CYP3A4 substrates you take and monitor accordingly.

Category 5: CNS Depressants

Combining Cobenfy with drugs that slow down the central nervous system can increase sedation, dizziness, and impaired thinking. Use extra caution with:

• Opioid pain medications (hydrocodone, oxycodone, codeine, morphine)
• Sleep medications (zolpidem, eszopiclone, temazepam)
• Benzodiazepines (alprazolam, lorazepam, diazepam)
• Muscle relaxants (cyclobenzaprine, carisoprodol)

Category 6: Potassium Supplements and Pramlintide

Potassium tablets or capsules may cause increased GI irritation when taken with Cobenfy due to reduced gut motility (slowed movement of food through the intestines). Pramlintide, a diabetes medication, slows stomach emptying — combining it with Cobenfy, which also slows GI motility, could worsen GI effects and affect how well other oral medications are absorbed. Tell your doctor if you take either of these.

Category 7: Alcohol

Alcohol is not a direct pharmacological interaction, but drinking while taking Cobenfy may worsen GI side effects including abdominal pain, diarrhea, and dizziness. If you drink regularly, discuss this with your prescriber. Trospium chloride extended-release forms (not Cobenfy capsules) have a documented interaction with alcohol that causes increased drug release — Cobenfy's immediate-release capsules have a different formulation, but caution with alcohol is still advisable.

GI Motility Drugs: Both Directions Matter

Because Cobenfy slows gastrointestinal motility (how fast food moves through your digestive tract), it can affect how well other oral medications are absorbed. Conversely, drugs that speed up GI motility may reduce Cobenfy's absorption. Your doctor may need to adjust doses of other medications based on how your GI system is working on Cobenfy.

What to Tell Your Doctor Before Starting Cobenfy

Before starting Cobenfy, provide your prescriber with a complete list of:

• All prescription medications and their doses
• Over-the-counter drugs (especially antihistamines, sleep aids, and antacids)
• Vitamins and supplements (including potassium, magnesium, and herbal products)
• Recreational drugs or regular alcohol use
• Any history of urinary problems, liver disease, kidney disease, or GI conditions

For more information on managing side effects related to these interactions, see our Cobenfy side effects guide.