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How does Vicodin work?

Vicodin is a prescription medicine that helps in managing pain–how does it work?

Pain, according to the International Association for the Study of Pain, is described as a negative sensory and emotional experience, linked to actual or potential tissue damage. It is classified into two types: acute and chronic pain. Acute pain is a type of pain considered to be generally sharp and lasting only for a short duration. It helps warn the individual about an injury to the body and is usually resolved following treatment. How do pain medications, such as Vicodin, work?

Chronic pain is generally described as pain lasting over three months or the normal tissue healing time. This type of pain can probably occur because of an underlying injury, medical condition, or treatment. It can persist even after the injury has been healed. This may be due to nerve damage, leading to the continuous triggering of pain signals throughout the brain and the rest of the nervous system for longer durations. People can experience chronic pain in the absence of any prior or obvious injury. Chronic pain is linked to medical conditions such as degenerative joint diseases (arthritis), fibromyalgia, cancer, and headaches.

There are several treatments available to help manage pain. These treatments include prescription medications, such as opioid analgesics, as well as physical and psychological therapies.

Opioid analgesics, also referred to as narcotic analgesics, are generally prescribed to relieve moderate to severe pain from surgery, cancer or other chronic medical illnesses. Some of these medications contain a combination of an opioid pain reliever and a non-opioid analgesic, such as an aspirin or acetaminophen. Vicodin is amongst some of the most commonly prescribed opioid analgesics for treating moderate or severe pain of both acute and chronic types.

How does Vicodin work?

Vicodin is made from the combination of hydrocodone and acetaminophen. This combination helps increase pain relief. It also lowers hydrocodone uptake by the body due to the side effects of acetaminophen.

Hydrocodone, an opioid analgesic, binds to the opioid receptors in the brain and the nervous system after entering the body. This results in the drug interfering with the pain signal pathways in the brain and helps in relieving the pain in the body.

Acetaminophen, a non-opioid pain reliever, helps in reducing the fever, pain, and inflammation. According to some studies, this is done by inhibiting the production of the hormone prostaglandins, produced in response to an injury or infection, in the central nervous system. In a 2008 study, researchers suggest the effects of acetaminophen may be induced by the drug activating the descending serotonergic pain pathways in the central nervous system.

Vicodin is taken orally in the form of either a pill, tablet, or syrup. The drug comes in three different forms (Vicodin, Vicodin ES, and Vicodin HP). The dosage is prescribed by the doctor and depends on the particular form of Vicodin prescribed, as well as the individual’s medical condition and their response to treatment.

How long does Vicodin take to work?

Patients can generally expect to begin feeling the effects of Vicodin in about less than an hour after taking it. The effects usually last between four and six hours. However, for extended-release tablets, it can take up to twelve hours to experience the effects of the drug.

Risks of taking Vicodin

Common side effects include light-headedness, dizziness, nausea, and vomiting. Patients may also experience side effects such as constipation, lethargy, drowsiness, skin rash, and urinary retention.

Vicodin can potentially be habit forming, causing physical and psychological dependence on the drug.

People with prior history of drug and alcohol addiction as well as depression or mental illness are considered to be at a higher risk of becoming addicted to the drug. These patients are carefully monitored by their doctor for any signs of addiction to the medication.

Patients can experience withdrawal symptoms if they suddenly stop taking the medication or the dosage is significantly lowered. This can occur for individuals taking the drug for long periods. Withdrawal can be characterized by symptoms such as anxiety, perspiration, nausea, restlessness, elevated blood pressure, heart rate, or breathing.

Patients can potentially develop serious life-threatening respiratory problems from taking the drug, particularly during the first twenty-four to seventy-two hours after initiating treatment or the time at which their dose is raised. They will need to talk to their doctor if they have trouble breathing or have respiratory disorders such as asthma or lung disease. It is likely that the doctor may ask the individual to stop taking the medication under these conditions.

Vicodin is linked to liver failure due to an accidental overdose of acetaminophen from the patient possibly taking more than the prescribed dosage of the medication. Patients are warned to not drink alcohol, while taking this medication as it can increase the risk of liver damage.

Both hydrocodone and acetaminophen are primarily metabolized by the liver into inactive forms. However, in people with liver disease, serum concentrations of the drug may be elevated. Also, in these patients, the drug may stay in the blood for longer than normal.

Vicodin drug interactions with other medications

Vicodin, taken along with medications inhibiting the enzyme CYP3A4, can possibly lead to the rise in hydrocodone levels in the blood plasma. This can elevate or prolong the effects of the drug. Patients may also experience the side effects of Vicodin including trouble breathing. Stopping the CY3A4 inhibitor or using a medication enhancing the enzyme, can decrease hydrocodone concentrations in the plasma. This can reduce the effects of the opioid pain reliever and the patient can likely experience withdrawal symptoms.

Patients taking Vicodin with central nervous system (CNS) depressants such as muscle relaxants, tranquilizers, sedatives, or general anaesthesia can be at an increased risk of low blood pressure, slow or shallow breathing, sedation, or coma.

Vicodin lowers the effect of diuretics for patients taking both drugs. This is because opioids enable the release of the anti-diuretic hormone. Individuals using Vicodin with anticholinergic drugs may be at a greater risk of urinary retention or constipation.

Written by Ranjani Sabarinathan, MSc                                                                                      


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