Drug addiction evolves from physical dependence on a drug to compulsive-drug seeking behavior with negative consequences, according to the "Clinical Textbook of Addictive Disorders." Opiate drugs are available by prescription for pain relief as well as for the treatment of addiction to opiate "street drugs", such as heroin. Hospitals administer opiates such as morphine intravenously for pain relief, while clinicians can prescribe drugs that contain such opiates as codeine or oxycodone. Physical dependence on opiates results in withdrawal symptoms as the drug is metabolized out of the body. (See Reference 1)
Physical Dependence and Withdrawal
Opiate drugs function to lessen pain, in part by inhibiting cells that are responsible for conveying sensory information. According to "Essential Psychopharmacology," this inhibition also affects the autonomic nervous system responsible for "fight or flight" actions. Accordingly, sudden withdrawal of the drug results in a "rebound effect", whereby the autonomic nervous system suddenly lacks inhibition and becomes hyperactive. The physical symptoms of withdrawal include diarrhea, runny nose, watery eyes, yawning, muscle aches, racing heart, dilated pupils and insomnia. (See Reference 2) Tapering the dosage of the opiate drug slowly can help to reduce withdrawal symptoms, according to the "Handbook of Addiction Psychopharmacology." (See Reference 3)
Tolerance
Opiate drugs interact with special proteins on the surfaces of cells known as receptors. "Essential Psychopharmacology" explains that as cells are exposed to increasing amounts of opiate drugs over time, they begin to diminish in the number of receptors that they keep on their surfaces. This is one way that the body attempts to adapt to the constant presence of the drug. However, it also causes cells to become less responsive to the amount of drug that was formerly needed to experience the desired effects--a phenomenon known as tolerance. This leads to a cycle in which the user increases the drug dosage in order to feel good while the body adapts to function as usual. (See Reference 2)
Drug-Seeking With Negative Consequences
MedLine Plus states that drug dependance leads a user to continue to use drugs, even though it negatively affects life at home, work or school. An opiate-addicted individual may stop caring about personal hygiene or physical appearance, for example, because of preoccupation with obtaining and using drugs. Additionally, the addict may spend excessive amounts of money on drugs instead of paying bills or buying food. Recognizing that they have a problem, the person may wish to cut down or stop using opiates; however, lack of control is one of the hallmarks of addiction. (See Reference 4)
References
- "Clinical Textbook of Addictive Disorders (Third Edition)"; Richard J. Francis et al.; 2005
- "Essential Psychopharmacology: Neuroscientific Basis and Practical Applications (2nd Edition)"; Stephen M. Stahl; 2002
- "Clinical Manual of Addiction Psychopharmacology"; Henry R. Kranzler, M.D. and Domenic A. Ciraulo, M.D.; 2005
- Drug Dependance: MedLine Plus Medical Encyclopedia
