Zydol Side Effects

Zydol is one of the brand names for tramadol hydrochloride, sold in the United Kingdom, Ireland and Australia. Tramadol was developed in the 1970s and was first approved for use in the United States by the Food and Drug Administration in 1995. Zydol treats moderate to severe pain, particularly neuralgia. Zydol works as a weak opioid agonist; it also increases the overall availability of serotonin and norepinephrine. Side effects vary, depending on dose and the patient's level of tolerance.

Gastrointestinal Disturbances

According to Drugs.com, in the first 90 days, nausea occurs in 40 percent of patients, and constipation in 46 percent. Opiates and medications that increase serotonin levels commonly affect the digestive system. Zydol affects the mu-opioid receptors, many of which are found in the intestinal tract. As a result, the gastrointestinal tract slows down. Other reported gastrointestinal upsets include diarrhea, vomiting, indigestion, loss of appetite, flatulence, dry mouth and abdominal pain.

Sleep and Wake Disturbances

According to Drugs.com, patients taking tramadol can experience drowsiness and insomnia. These effects may be dose-dependent and normal sleep and wake patterns may return after the medication becomes tolerated. One of the possible mechanisms for Zydol's ability to cause sleep disturbances relates to how opiates disrupt adenosine in the body. In the December 2009 issue of "Anesthesiology," Dr. Max Kelz and Jason Moore state that opiates inhibit adenosine, which is required for the body to initiate sleep.

Itchy Skin

According to Drugs.com. itchy skin occurs in 11 percent of patients taking Zydol. Opiates cause itching by releasing histamine, which reacts at the skin causing mild inflammation. Dr. Arjunan Ganesh and Dr. Maxwell Lynne at the Children's Hospital of Philadelphia state that itching may also be caused by drugs that increase serotonin.

Flushing

According to Drugs.com, flushing can occurs in patients taking tramadol. Opiates can cause dilation of the blood vessels, allowing an increase of blood congestion in the face and limbs. According to the Netherlands Pharmacovigilance Centre, flushing and hot flashes occur with patients taking tramadol because of increases in serotonin and norepinephrine. In most cases the flushing goes away after only a few days.