Hydrocodone/homatropine syrup is a cough suppressant consisting of an anticholinergic and a narcotic, according to Drugs.com. The anticholinergic dries secretions, while hydrocodone, the narcotic, suppresses the brain's cough reflex. Patients with morphine-related or other allergies, or who are taking sodium oxybate, need to contact their doctors before taking the medication.
Sodium oxybate, marketed as Xyrem and called GHB, may increase the risk of experiencing side effects associated with hydrocodone/homatropine syrup, such as blurred vision, constipation and nausea, notes Drugs.com. Naltrexone may make the cough suppressant less effective. If a patient taking hydrocodone/homatropine syrup misses a dose, the patient needs to take it as soon as possible, but is cautioned to not take two doses at one time. Because hydrocodone is an opiate analgesic, a patient can develop an addition to it, states MedlinePlus.