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Oxybutynin

Medication antimuscarinic other
Aka: Ditropan
Brands seen in Singapore: Obutin
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Overactive bladder — urgency, frequency, leaking
Take with
With or without food · alcohol adds to the drowsiness
Pros & cons
Pros
  • HealthHub: eases urgency, leaking and frequency
  • HealthHub: taken with or without food
  • 5 mg tablets are the SG registered strength
Cons
  • Dry mouth, dry eyes and constipation are common
  • Drowsiness and blurred vision can affect driving
  • Overheating in hot weather is a listed effect
Sources
  1. HSA — Listing of Registered Therapeutic Products (data.gov.sg d_767279312753558cbf19d48344577084), Forensicclassification column; cached at /tmp/hsa_all.json and filtered locally, not re-fetched · read 2026-08-27
    what it says
    “OBUTIN TABLETS 5 mg [SIN11215P] | OXYBUTYNIN CHLORIDE | Prescription Only | G04BD04 | TABLET | 5 mg — the only oxybutynin row in the 5,511-row register”
  2. MOH National Drug Formulary (Singapore) — OBUTIN TABLETS 5 MG [SIN11215P], product information (no indication or dosing section is published for this product) · read 2026-08-27
    what it says
    “OBUTIN TABLETS 5 MG [SIN11215P] … OXYBUTYNIN CHLORIDE - 5 MG … Forensic Classification PRESCRIPTION ONLY MEDICINES … ATC code G04BD04 … Prescription-only Medicines with Exemptions for Supply without Prescription NA”
  3. HealthHub (MOH Singapore) — Oxybutynin, medication information leaflet, last reviewed 08 April 2026 · read 2026-08-27
    what it says
    “Oxybutynin is used to treat a condition called overactive bladder. Overactive bladder happens when you cannot control your bladder muscle.”
  4. HealthHub (MOH Singapore) — Oxybutynin, symptoms it addresses · read 2026-08-27
    what it says
    “not being able to control when to empty your bladder, where you get a strong need to urinate with leaking or wetting incidence (urinary incontinence) … a strong need to urinate right away (urgency) … urinating often (frequency)”
  5. HealthHub (MOH Singapore) — Oxybutynin, how to take it · read 2026-08-27
    what it says
    “Do not stop taking your medication without checking with your healthcare professional. You may take this medication with or without food.”
  6. HealthHub (MOH Singapore) — Oxybutynin, common side effects · read 2026-08-27
    what it says
    “Drowsiness May affect your ability to drive and use machinery … Dizziness … Dry Mouth … Dry Eyes … Constipation … Overheating of the body … Blurred vision … Headache”
  7. HealthHub (MOH Singapore) — Oxybutynin, precautions · read 2026-08-27
    what it says
    “You are not able to empty your bladder (urinary retention) … You have an eye problem called "uncontrolled narrow angle glaucoma" … You have liver, kidney or heart problems … myasthenia gravis … hyperthyroidism … Parkinson's disease or hiatus hernia”
  8. HealthHub (MOH Singapore) — Oxybutynin, precaution on cholinesterase inhibitors · read 2026-08-27
    what it says
    “You have dementia and is taking medications called cholinesterase inhibitors such as Galantamine, Donepezil, Rivastigmine as these combinations may affect the condition.”
  9. HealthHub (MOH Singapore) — Oxybutynin, food and medication to avoid · read 2026-08-27
    what it says
    “Avoid drinking alcohol as it may increase the risk of dizziness, light-headedness or drowsiness.”
  10. US FDA label — Oxybutynin Chloride tablets (A-S Medication Solutions, effective 2025-11-18), Dosage and Administration, via openFDA · read 2026-08-27
    what it says
    “Adults The usual dose is one 5-mg tablet two to three times a day. The maximum recommended dose is one 5-mg tablet four times a day.”
  11. US FDA label — Oxybutynin Chloride tablets, Dosage and Administration: frail elderly, via openFDA · read 2026-08-27
    what it says
    “A lower starting dose of 2.5 mg two or three times a day is recommended for the frail elderly.”
  12. US FDA label — Oxybutynin Chloride tablets, Drug Interactions, via openFDA · read 2026-08-27
    what it says
    “The concomitant use of oxybutynin with other anticholinergic drugs … may increase the frequency and/or severity of such effects. … Anticholinergic agents may also antagonize the effects of prokinetic agents, such as metoclopramide.”
  13. US FDA label — Oxybutynin Chloride tablets, Drug Interactions: CYP3A4 inhibitors, via openFDA · read 2026-08-27
    what it says
    “Mean oxybutynin chloride plasma concentrations were approximately 3 to 4 fold higher when oxybutynin chloride was administered with ketoconazole, a potent CYP3A4 inhibitor. Other inhibitors … macrolide antibiotics (e.g., erythromycin and clarithromycin), may alter oxybutynin mean pharmacokinetic parameters”
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Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.