Can I take Morphine and Solifenacin together?
Drug interaction guide
Originally published 25 Jan 2026
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Taking morphine and solifenacin together can significantly increase the risk of severe constipation and difficulty passing urine (urinary retention). It may also lead to an increased risk of confusion, dry mouth, blurred vision, and extreme sleepiness.
Why this happens
Both drugs have 'anticholinergic' effects, meaning they slow down the movement of the gut and the bladder. When used together, these effects add up, making it much harder for your body to move waste through your system or empty your bladder.
What you should do
Use this combination with caution. Ensure you drink plenty of water and eat a high-fibre diet to prevent constipation. If you find it difficult to urinate, or if you experience severe stomach pain or confusion, contact your doctor immediately. Your doctor may need to adjust your doses.
Important precautions
Respiratory conditions (e.g. asthma, COPD)
Morphine can cause life-threatening breathing difficulties. Do not take this medicine if you have severe asthma or breathing problems.
Opioid dependence and withdrawal
Morphine carries a high risk of addiction and dependence. Long-term use can lead to withdrawal symptoms if stopped suddenly; always follow a tapering schedule.
Glaucoma
Do not take solifenacin if you have narrow-angle glaucoma that is not being effectively treated, as it can increase the pressure in your eyes.
Urinary or gastric retention
Do not take solifenacin if you have severe difficulty passing urine or if you have a condition where your stomach empties very slowly (gastric retention).
Food and drink warnings
Alcohol
It is best to avoid or strictly limit alcohol while taking morphine. Combining alcohol with morphine significantly increases the risk of dangerous side effects, such as extreme sleepiness, breathing difficulties, and a potentially fatal overdose.
Grapefruit juice
Avoid drinking large amounts of grapefruit juice. Grapefruit can increase the level of solifenacin in your blood, which may increase the risk of side effects like dry mouth, blurred vision, and constipation.
Caffeine (Coffee, Tea, Energy drinks)
While not a direct chemical interaction, caffeine is a bladder irritant and a diuretic. Since solifenacin is used to treat overactive bladder symptoms, consuming caffeine may reduce the effectiveness of your treatment.
Using other medicines
Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
Article also available in English, German, Spanish, French, Italian, Portuguese, Hindi, Hebrew, Arabic, and Swedish.
25 Jan 2026 | Originally published
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