Brief Answer:
More information is needed.

Detailed Answer:

Hello,

Many medicines that used to treat fungal infections may cause gastrointestinal disturbances such as constipation. Usually, medication induced constipation resolves after stopping the medicine.

I would like to ask few questions that will help me to give more specific answer:
What anti-fungal medicine did your husband take for toenail infection?
Did the constipation started during the treatment with the anti-fungal medicine or after the treatment?
How many bowel movements is he having in a week?
What laxative medicine is he taking to aid bowel movement?
Is he taking any other medications?
Does he have any other medical conditions?

Simply increasing fluid intake, increasing meals that contains more fiber (vegetables, fruits, cereals, wholegrains) and doing regular exercises stimulate bowel movements and may help to relief constipation. If the constipation is long enough and resistant to medical management it may be from underlying medical condition which needs further medical investigation.

Please reply me answers of above asked questions, so that I can guide you better. I will be happy to help you further.
Thank you.

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Brief Answer:
Please, try following life style changes...

Detailed Answer:
Hello,

Thank you for the follow-up.

Oral terbinafine may cause constipation. But it is less likely that terbinafine caused constipation will continue several weeks after stopping the medicine. The most common causes of constipation in elderly are being physically inactive, low fluid intake and changes in diet.
Dulcolax (bisacodyl) is a bowel stimulant that causes bowel contractions and promotes evacuation of the colon. But it is mainly used for the short-term treatment of constipation, as long time use may cause drug tolerance requiring increasing the dose.
You may stop Dulcolax and try following life style changes:
Try to increase water intake and do regular exercises. It is normal to have bowel movements once in two days (at least 3 bowel movements per week without straining it is normal).
Try to increase your daily fiber intake by eating plenty of vegetables, cereals, wholemeal bread, wholegrains, oats or seeds. Fiber absorbs water into the gut and makes the stool softer and easier to pass. You may try fiber supplements such as psyllium powder that can be used for the same purpose. Fiber supplements works fine with adequate fluid intake. You should take at least one glass of water with psyllium and one more glass after taking it.

If the above life style changes will not help within a week, please, contact your doctor. Chronic constipation may be secondary from other medical conditions.

Hope I have answered your query. Let me know if I can assist you further.
Thank you

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