Codeine phosphorus is an opioid pain medication that is used to treat mild to moderately severe pain. It can be used to treat both acute and chronic pain and is available by prescription. Some common uses of codeine phosphorus include treating pain after surgery, injuries, dental work, or during cancer treatment. It is also used to relieve coughs and symptoms of colds and flu. Codeine phosphorus works by binding to opioid receptors in the brain and spinal cord to block pain signals. While it can be effective, it does have the potential for abuse and addiction. When used appropriately under medical supervision, codeine phosphorus can provide important pain relief.
Medical Uses
Pain Relief
Codeine phosphorus is most commonly prescribed for relief of mild to moderate pain. This includes both acute pain, such as after surgery or an injury, and chronic pain from conditions like arthritis, cancer, or neuropathy. Codeine helps reduce pain signals reaching the brain so a person feels less discomfort. It may be used on its own or combined with non-opioid pain relievers like acetaminophen or aspirin. Codeine is considered weaker than other opioid medications like morphine or oxycodone, so it may be preferred for milder pain or people who are more sensitive to stronger opioids. The typical dose for codeine pain relief is 15-60 mg every 4 hours as needed.
Cough Suppressant
Codeine is also used for its cough suppressing effects. It can reduce the reflex to cough by acting on the brain’s cough center. Codeine is found in some prescription cough syrups and cold medicines in doses of 10-20 mg per dose. By suppressing the urge to cough, codeine improves comfort and reduces pain from constant coughing. However, codeine should be used cautiously in individuals with lung disease, as excess suppression of the cough reflex could lead to poor airway clearance.
Diarrhea Treatment
As an opioid medication, codeine can help treat diarrhea by slowing down motility and contractions in the intestines. This allows more time for water absorption. Codeine may be used short-term for diarrhea relief, such as with acute infectious diarrhea. The typical antidiarrheal dose is 30-60 mg every 4-6 hours as needed. However, other anti-diarrheal agents are usually preferred over opioids due to the risks of codeine.
How Codeine Works
Codeine produces its effects by acting as an opioid agonist. It binds to and activates opioid receptors located throughout the body, but primarily in the central nervous system and gastrointestinal tract.
Pain Relief Mechanism
When codeine binds to mu-opioid receptors in the brain and spinal cord, it mimics the effects of naturally occurring endorphins. This blocks the transmission of pain signals to the brain, reducing the sensation of pain. Codeine also acts at kappa opioid receptors, which further dampens pain perception.
Cough Suppression
For cough relief, codeine acts centrally in the medulla oblongata of the brain, which contains the cough center. Opioid receptors here regulate cough reflex sensitivity. Codeine suppresses the urge to cough by interacting with these brain receptors.
Anti-Diarrheal Effects
In the gastrointestinal system, codeine slows motility by acting on mu-opioid receptors in the gut. This increases muscle tone and contractions in the intestines, allowing more time for water reabsorption and resulting in less watery stools.
Side Effects
While codeine can be an effective medication, it also has the potential for side effects. Some of the possible side effects of codeine phosphate include:
Constipation
One of the most common side effects of opioids like codeine is constipation. Codeine slows contractions in the intestines, which can allow stools to become hard and difficult to pass. Staying hydrated, eating a high fiber diet, and taking laxatives can help prevent opioid-induced constipation.
Nausea and Vomiting
Nausea and vomiting are also fairly common, reported in up to a third of people taking codeine. Taking the medication with food can help minimize GI upset. Anti-nausea medications may be prescribed if nausea is severe.
Drowsiness
Codeine can cause drowsiness as it acts on the central nervous system. This side effect may be more pronounced when first starting treatment but often improves over time. Avoiding alcohol and driving or operating heavy machinery until the effects are known can reduce risks.
Itching
Mild itching is not uncommon with opioid use. Antihistamines can provide relief if pruritus becomes bothersome.
Headache
Headaches may occur due to codeine’s effects on pain perception in the brain or due to withdrawal between doses. Staying hydrated and limiting caffeine may help prevent headaches.
Dizziness
Dizziness can occur as codeine may lower blood pressure in some individuals. Rising slowly from sitting or lying down helps minimize the risk of becoming dizzy.
Breathing Difficulties
Codeine is a depressant and can slow breathing rate. Serious respiratory depression is possible at high doses, especially in those not tolerant to opioids. Seek medical attention for signs of overdose like extremely slow breathing.
Tolerance and Dependence
With prolonged use, tolerance to codeine can develop requiring higher doses for pain relief. Psychological and physical dependence is also possible. Working closely with a doctor prevents increasing doses too quickly or without need.
Warnings and Precautions
There are some important warnings and precautions to consider before using codeine phosphate:
Risk of Addiction
Codeine does carry a risk of addiction, even when taken exactly as prescribed. Use the lowest effective dose and avoid increasing it without consulting a doctor. Seek help if addiction becomes a concern.
Respiratory Depression
High doses can dangerously slow or even stop breathing, which can be fatal. Extra precaution is needed for high risk groups like the elderly. Avoid other CNS depressants like sedatives or alcohol.
Use in Children
Codeine should not be given to children under 12 years old for pain and under 18 years for cough. Use is associated with more side effects and variable metabolism of codeine in younger patients.
Allergic Reaction
Codeine, like other opioids, may cause potentially life-threatening allergic reactions in some people even on first use. Seek immediate medical help for rash, swelling, or breathing problems.
Pregnancy Risks
Codeine is not recommended for pregnant women, especially in the third trimester. Opioid withdrawal can occur in newborns if mothers use codeine right before delivery.
Severe Kidney or Liver Dysfunction
Kidney or liver impairment may prevent appropriate breakdown and clearance of codeine from the body, leading to more side effects or overdose. Dose adjustments or alternatives may be required.
Surgery Restrictions
Be sure to inform doctors about codeine use before any surgery, as dosing alterations may be required with anesthesia or pain medications. Abruptly stopping codeine prior to surgery can also cause withdrawal.
Interactions
Codeine can potentially interact with a variety of medications and substances. Some interactions to be aware of include:
Alcohol
Combining codeine and alcohol enhances central nervous system depression and should be avoided completely. The combination severely impairs coordination, thinking, and judgment and may lead to respiratory failure.
Antihistamines
Antihistamines like Benadryl can add to the sedating effects of codeine. Use caution driving or performing hazardous tasks after taking both medications.
CNS Depressants
Medications like benzodiazepines, barbiturates, antidepressants, and antipsychotics may all amplify the sedation, drowsiness, and respiratory depression of codeine.
Muscle Relaxants
Muscle relaxers also depress the central nervous system and can further slow breathing when combined with codeine. Use together only with medical guidance.
MAO Inhibitors
Drugs like phenelzine and tranylcypromine interact with codeine and can lead to hypertension, headache, hyperpyrexia, or seizures. Allow 14 days between stopping an MAOI before starting codeine.
Warfarin
Codeine competes with warfarin for liver enzymes and can increase warfarin levels in the body, raising bleeding risks. More frequent INR monitoring is required.
| Medication/Substance | Effect of Interaction |
|---|---|
| Alcohol | Enhanced CNS and respiratory depression |
| Antihistamines | Increased sedation |
| CNS Depressants | Additive CNS and respiratory depression |
| Muscle Relaxants | Increased risk of respiratory depression |
| MAO Inhibitors | Risk of hypertension, hyperpyrexia, seizures |
| Warfarin | Raised warfarin levels and bleeding risk |
Dosing
The dose of codeine phosphate depends on the person and condition being treated. Some general dosing guidelines include:
Pain Relief
For mild to moderate pain relief, the typical dose range is 15-60 mg every 4 to 6 hours as needed. Maximum daily doses should not exceed 360 mg per day.
Cough Suppression
When used for coughs, common doses for adults range from 10-20 mg every 4-6 hours. For children over 12 years old, 5-10 mg doses are appropriate. Most prescription cough syrups contain 10 mg codeine per 5 mL.
Diarrhea
For diarrhea, codeine doses are typically 30-60 mg every 4-6 hours as needed for no more than two days. Loperamide or other antidiarrheal agents are preferred, however.
Individual Factors
Lower doses and less frequent dosing is required for elderly patients, those with kidney impairment, and individuals of smaller stature. Children under 12 should avoid codeine for pain and under 18 for cough.
Formulations
Codeine phosphate is available in several formulations:
Tablets
Codeine tablet strengths usually range from 15 mg to 60 mg. Tablets provide convenient oral dosing.
Oral Solutions
Oral solutions containing codeine allow for flexible dosing, especially when lower doses are needed. Concentrations typically range from 1-2 mg/mL.
Injections
Injectable codeine can be given intravenously or intramuscularly for more rapid pain relief, such as after surgery. Concentrations are often 20-40 mg/mL.
Compound Preparations
Codeine is combined with other medications in some formulations:
– Codeine/acetaminophen tablets (ex. Tylenol #3)
– Codeine/antihistamine syrups for cough (ex. Phenergan with Codeine)
– Codeine/antipyretic powders for pain/fever
Abuse Potential
As an opioid drug, codeine does carry a risk of abuse and addiction, even at prescribed doses. Warning signs of codeine misuse or dependency include:
– Taking more frequent or higher doses than prescribed
– Continuing use despite harm or negative consequences
– Intense drug cravings
– Building tolerance requiring more codeine for the same effect
– Appearing intoxicated frequently
– Isolation and secretive behavior
– Financial issues due to spending money on codeine
A combination of behavior therapies and medications like methadone, buprenorphine, or naltrexone may be used for codeine addiction treatment. Seeking professional help is important for overcoming opioid dependence.
Overdose
Codeine overdose occurs when excessive doses lead to dangerous CNS and respiratory depression. Signs of overdose include:
– Extreme drowsiness, inability to stay awake
– Slow, shallow, or stopped breathing
– Pinpoint pupils
– Clammy, cold skin
– Limp muscles/loss of muscle tone
– Slow/irregular heartbeat
– Loss of consciousness
A codeine overdose is a medical emergency. Call 911 immediately if an overdose is suspected. Give naloxone if available while awaiting emergency help, as it can rapidly reverse opioid overdose effects. Other emergency treatment focuses on supporting respiratory and cardiac function.
Conclusion
Codeine phosphate is an effective oral opioid medication that serves an important role for treating mild to moderate pain and cough when used responsibly under medical supervision. However, the risks of side effects, interactions, addiction and overdose require careful consideration. Work closely with your doctor when using codeine and never increase doses or frequency on your own. Safe use requires following prescription instructions carefully and being aware of potential dangers. With judicious medical use, codeine can provide significant relief when needed. But vigilance is required to keep risks in check.