Vicodin (hydrocodone and acetaminophen combination) is one of the most prescribed pain medicines. The special combination of acetaminophen and hydrocodone makes Vicodin to be a powerful antipyretic, analgesic and antitussive medicine. The two compounds act in synergy in the management of cough symptoms, fever and pain (Chabdrasekharan, et al, 2002). In the paper, individual pharmacokinetics of the two compounds that make up Vicodin will be discussed giving details the mode of action of both compounds. Indications of Vicodin will also be considered highlighting when the drug is used and the possible side effects.
There are dangers that result following concomitant Vicodin administration with other drugs. The paper will examine these dangers and provide co-morbidity and age limitations when using Vicodin. Monitoring discussion will credit the importance of physician monitoring in managing any side effects that may arise. The paper will conclude by stating the exact dosage recommended among patients in order to avoid overdose. Introduction Vicodin (hydrocodone bitartrate and acetaminophen) is an antitussive antipyretic and analgesic drug used for managing pain symptoms. It is presented in the form of tablets which can be administered through oral route.
Hydrocodone bitartrate, chemically 4, 5? -epoxy-3-methoxy-17-methomorphinan-6-one tartrate is an antitussive and an opioid analgesic which occurs as fine crystalline or white crystalline powder. Acetaminophen, chemically 4’-hydroxyaxetanilide (C8H9NO2), is sparingly bitter, white in color crystalline powder. It is a non salicylate, non opiate and non steroidal anti-inflammatory drug (NSAID) that elicits antipyretic and analgesic properties partly through the inhibition of cyclooxygenase (COX) activity (Chandrasekharan et al, 2002). Cyclooxygenase enzymes are involved in prostaglandin production.
Vicodin contains other inactive compounds which include colloidal silicon dioxide, croscarmellose sodium, starch, dibasic calcium phosphate, microcrystalline cellulose, stearic acid and providone. These compounds do not possess any pharmacological activity although they help in improving the efficacy and stability of the active molecules. Pharmacokinetics Vicodin contains hydrocodone and acetaminophen which have different pharmacological properties. Hydrocodone is a narcotic analgesic which sooths pain by actively binding to the opioid receptors in the spinal cord and the brain.
Hydrocodone specifically acts on the smooth muscles and the central nervous system (CNS). Hydrocodone is also an example of antitussive agents that elicit a number of effects that are qualitatively analogous to those elicited by codeine. Apart from the analgesic property of hydrocodone, it produces mental clouding, mood changes and drowsiness. The feeling of drowsiness may be intensified if patients take alcohol with hydrocodone. Drowsiness results due to specific drug interaction with monoamine oxidase (MAO) inhibitors.
Once in the liver, hydrocodone undergoes biotransformation processes which include N-demethylation, O-demethylation as well as 6-keto reduction to produce 6- ? -hydroxy metabolites and 6- ? -hydroxy-metabolites. Hydrocodone has a maximum serum half life (t1/2) of 3. 8 hours and the mean peak concentration of 23. 6mg/mL following an oral dose of 10mg of hydrocodone. The liver cytochrome P450 specifically CYP2D6 converts hydrocodone into hydromorphone. Hydromorphone is a type of opioid which is even more potent than hydrocodone (Draganov, et al. 2000).
In Caucasians, CYP2D6 enzymes are poor metabolizers of hydrocodone and therefore Caucasians have a reduced function of the metabolic pathway which converts hydrocodone to hydromorphone. However, pharmacodynamic studies have shown that the effectiveness of hydrocodone among the Caucasians population is independent of the metabolic pathway which converts hydrocodone into hydromorphone (Draganov, et al. 2000). Acetaminophen elicits its antipyretic activity through the heat regulating centers in the hypothalamus. It mainly relieves pain by inhibiting the activity of prostaglandin synthetase.
Although therapeutic doses of the compound acetaminophen have little effects to the respiratory and cardiovascular systems, toxic doses may result into cardiac failures and breathing difficulties. Acetaminophen is rapidly absorbed from the gastrointestinal tract (GIT). this is then distributed throughout the entire body tissues with plasma half-life of up to 3 hours (Smith, 2009). Liver damage and overdoses have been found to increase the plasma half-life. Acetaminophen removal from body tissues is by way of conjugation in the liver and the subsequent excretion of metabolites through the kidney.
Almost 85 percent of acetaminophen oral dose appears within 24 hours in the urine mainly as conjugates of glucuronide. However, other conjugates as well as the unchanged acetaminophen may be present in urine (Khashab, Tector & Kwo, 2007). Indications Vicodin is used in the management of various pain symptoms such as acute or chronic pain in the body. The analgesic properties exhibited by both hydrocodone and acetaminophen form an effective synergy in the management of a wide range of both acute and chronic pains. Chronic pain is often difficult to control with drugs with single compounds.
Vicodin combines the properties of both acetaminophen and hydrocodone to become potent in managing chronic pain in the afflicted patients (Ho & Burton, 2007). Vicodin is used to manage cases of hyperthermia (elevated body temperatures) apart from reducing pain. The acetaminophen antipyretic property makes Vicodin to be used for this purpose. The antitussive property of hydrocodone makes Vicodin to be used in managing cough symptoms. Cough symptoms can be varied often presented as fever and pain. These can be managed easily using Vicodin which is a combination preparation of acetaminophen and hydrocodone (Ho & Burton, 2007).