Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Gelnique (Oxybutynin-topical). If you are concerned about side effects, discuss the risks and benefits of Gelnique (Oxybutynin-topical) with your doctor.

The following side effects have been reported by at least 1% of people taking Gelnique (Oxybutynin-topical). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• Constipation
• decreased sweating
• dizziness
• Dry Mouth
• headache
• rash
• skin dryness, itchiness, or redness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• abnormal vision
• difficulty urinating
• fast, uneven, or pounding heartbeat
• severe application-site reaction (blisters, numbness, redness, dryness, and/or pain)
• severe constipation

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a serious allergic reaction (swelling of face or throat, Hives, or difficulty breathing)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Gelnique (Oxybutynin-topical).

Each packet contains a 1 gram unit dose and each gram of gel contains 100 mg of oxybutynin chloride. Nonmedicinal ingredients: alcohol, glycerin, hydroxypropyl cellulose, purified water, and sodium hydroxide.

Do not use oxybutynin gel if you:

• are allergic to oxybutynin or any of the ingredients of the medication
• have urinary retention (problems emptying your bladder) or are at risk for it
• have gastric retention (stomach obstruction or problems affecting the passage and digestion of food) or are at risk for it
• have Myasthenia Gravis or are at risk for it
• have severe stomach problems
• have uncontrolled narrow-angle Glaucoma (an eye condition) or are at risk for it

There may be an interaction between oxybutynin gel and any of the following:

• aclidinium
• alcohol
• antihistamines (e.g., cetirizine, Chlorpheniramine, Dimenhydrinate, Diphenhydramine)
• antipsychotics (e.g., Chlorpromazine, Clozapine, Haloperidol, Quetiapine, Risperidone)
• atropine
• "azole" antifungals (e.g., itraconazole, ketoconazole, Voriconazole)
• belladonna
• Benztropine
• botulinum toxin
• Buprenorphine
• cannabis
• clidinium
• Cobicistat
• Cyclobenzaprine
• Darifenacin
• Disopyramide
• Donepezil
• Flavoxate
• Galantamine
• glycopyrrolate
• homatropine
• HIV protease inhibitors (e.g., darunavir, indinavir, lopinavir, saquinavir, tipranavir)
• ipratropium
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• Metoclopramide
• Mirabegron
• monoamine oxidase inhibitors (e.g.,  Moclobemide, Selegiline)
• narcotic medications (e.g., Morphine, Codeine)
• nefazodone
• orphenadrine
• potassium chloride
• quinidine
• Rivastigmine
• scopolamine
• Solifenacin
• thiazide diuretics (e.g., Hydrochlorothiazide, Indapamide)
• tiotropium
• Tolterodine
• Topiramate
• tricyclic antidepressants (e.g., Amitriptyline, Desipramine, Nortriptyline)
• Trospium
• umeclidinium

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Gelnique (Oxybutynin-topical). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Gelnique (Oxybutynin-topical).

Allergic reaction: A Anaphylaxis (severe allergic reaction) called angioedema (swelling of the face, hands, throat, and tongue) has been reported in people taking the oral form of oxybutynin (oxybutynin pills). If you experience any of these symptoms while using oxybutynin gel, seek immediate medical attention.

Bladder obstruction: If you have bladder obstruction, you should discuss with your doctor how Gelnique (Oxybutynin-topical) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Gelnique (Oxybutynin-topical), and whether any special monitoring is needed. You may be at risk of urinary retention (problems emptying your bladder). People with urinary retention should not use oxybutynin gel.

Gastrointestinal disorders: If you have constipation, difficulty emptying bowels, obstructive gastrointestinal disorder, Ulcerative Colitis, or gastroesophageal reflux, discuss with your doctor how Gelnique (Oxybutynin-topical) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Gelnique (Oxybutynin-topical), and whether any special monitoring is needed. You may be at risk of gastric retention (stomach obstruction or problems affecting the passage and digestion of food). People with gastric retention should not use oxybutynin gel.

Glaucoma: If you have controlled narrow-angle glaucoma, discuss the benefits and risks of Gelnique (Oxybutynin-topical) with your doctor. Oxybutynin may worsen this condition.

Heat: Oxybutynin gel may decrease sweating. Take care to stay cool (stay indoors, use air conditioning) to help prevent overheating in warm or hot temperatures.

Liver and kidney function: If you have reduced kidney or liver function, discuss with your doctor how Gelnique (Oxybutynin-topical) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Gelnique (Oxybutynin-topical), and whether any special monitoring is needed.

Skin conditions: You should avoid applying the medication on areas with Eczema, seborrhea, or psoriasis. If you have any of these conditions, discuss with your doctor how Gelnique (Oxybutynin-topical) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Gelnique (Oxybutynin-topical), and whether any special monitoring is needed.

Pregnancy: Gelnique (Oxybutynin-topical) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Gelnique (Oxybutynin-topical), contact your doctor immediately.

Breast-feeding: It is not known if oxybutynin passes into breast milk. If you are a breast-feeding mother and are taking Gelnique (Oxybutynin-topical), it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using Gelnique (Oxybutynin-topical) have not been established for children under 18 years old.