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Acupuncture Today
November, 2012, Vol. 13, Issue 11
 
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The Basics of Western Medicine Drugs: Part II

By Bruce H. Robinson, MD, FACS, MSOM (Hon)

I was motivated to write a series of articles on Western drugs because I received so much feedback from my colleagues who are licensed acupuncturists. They told me that they would like to know more about the medications their patients are on, prescribed by their Western physicians.

I also understand that this knowledge is important for those who are completing their training at an acupuncture college and have to pass the national or the California licensure examinations. In this second of three articles on Western drugs I would like to discuss pain medications, respiratory drugs, and drugs for gastrointestinal problems.

Drugs for Pain Control

Morphine is arguably the greatest drug of all time, as it is so powerful in relieving pain. It works when nothing else will, and is a godsend for those at the end of their lives with serious health problems such as metastatic cancer, who do not deserve to end their earthly existence with so much suffering.

Discovered in 1804, morphine was first distributed by Merck in 1827. Merck, the first modern drug company, was then a small chemist's shop in Germany, which quickly expanded to include an adjoining small drug factory. Morphine became more popular after the invention of the hypodermic needle and syringe in 1857, which made the drug have far more powerful effects (otherwise partly inactivated by the GI tract).

Unfortunately when drugs are powerful in their main effects they also tend to have powerful side effects. Side effects of morphine:

  • Respiratory depression, which can be life threatening.
  • Constipation, which can be severe.
  • Nausea and vomiting are not uncommon, especially with initial doses, which may later on go away with repeated use.
  • A curious spasm of the bile ducts which renders it unsafe to use in patients who have gallbladder disease or biliary colic from gallstones.

Because of these side effects of morphine, pharmacologists developed other opioid narcotics which are also powerful pain-killers, although not quite as strong as morphine. They also have side effects, but less so than morphine. These include levophanol (Levo-dromoran®), oxycodone (OxyContin®), hydrocodone (Hycodan®; many other names), hydromorphone (Dilaudid®), methadone (Dolophine®) and the popular drug meperidine (Demerol®).

Methadone is less addicting than some of the other narcotics, and it does not require injections. It is used in drug addiction clinics to help addicts withdraw from narcotics.

Another powerful narcotic that has become very popular as a preoperative medication is fentanyl (Sublimaze®). It has the benefit of being less likely than morphine to cause respiratory depression.

Side effects of these other narcotic agents are similar to morphine, but less pronounced. Especially think constipation with all these drugs. All of them are addictive when taken for prolonged periods of time and all lead to tolerance, requiring more of the drug for the same effect. Drug withdrawal can be challenging.

There is also a group of weaker narcotic analgesics, the classic of which is codeine. A small percentage of codeine is converted to morphine when it is ingested by mouth (about 10%). Its pain-killer activity is due to the morphine. There are also other similar drugs, such as Talwin®, Darvon®, and Nubain® which are milder in their analgesia than the strong narcotics and have the same side effects to a lesser degree (nausea, constipation are common).

Combinations of weak narcotics and NSAIDs (non-steroidal anti-inflammatory drugs) are among the most popular drugs. All require prescriptions and are used for severe headaches, recovery from surgery, dental pain, muscular aches and pains, where the "big guns" are not needed, with all their addiction potential.

Here is a good list:

  • Tylenol with codeine No.3: 30 mg of codeine and 325 mg of Tylenol
  • Tylenol with codeine No. 4: 60 mg of codeine and 300 mg of Tylenol
  • Vicodin: 5 mg hydrocodone and 650 mg of Tylenol
  • Percocet: 5 mg oxycodone and 325 mg of Tylenol
  • Percodan: 4.5 mg of hydrocodone, 0.38 mg oxycodone, 325 mg aspirin
  • Fiorinal with codeine No. 3: 30 mg of codeine, 325 mg of Tylenol, 40 mg of caffeine, and 50 mg butalbital (used for migraine headaches)

So, in terms of treating pain with medications, there are three levels:

  1. Mild to moderate pain: there is usage of aspirin, Tylenol, Alleve, Advil, Motrin, or other NSAIDs. No prescription is required.
  2. Moderately severe pain: there is usage of Tylenol with codeine, Vicodin, Percocet, or the generics of these drugs. A prescription is needed to obtain these drugs.
  3. Very severe pain: full narcotic are often used such as: Morphine, Demerol and OxyContin, which is often administered as an absorbable patch: a very popular drug in extended care facilities and with the VNA, the Visiting Nurses Association, which deals with terminal cancer patients in the home.

Narcotic Antagonists

Two drugs are widely used in hospital and emergency rooms to combat narcotic overdose: naloxone (Narcan®) and naltrexone (ReVia®). Both block opioid receptors and reverse the effects of narcotics. They are commonly used in cases of narcotic overdose in the hospital with respiratory depression, hypotension, or with a drug addict who has suffered an overdose.

Before we discuss respiratory drugs we need to briefly review the autonomic nervous system, which controls all the unconscious, automatic functions of our bodies, because these drugs affect this nervous system.

There are two divisions: the sympathetic nervous system: the fight or flight responses of the body; stimulated by fear or anger, and the parasympathetic nervous system - the housekeeper nervous system: in charge of all body processes when we are at rest and not feeling threatened.

These two divisions of the autonomic nervous system counterbalance each other: e.g., the sympathetic makes the heart beat faster; the parasympathetic makes it beat more slowly. In many ways they have a yin/yang balance with each other.

The neurotransmitter of the sympathetic nervous system is norepinephrine, a catecholamine. It is also stimulated by other catecholamines such as epinephrine and dopamine, and also by adrenergic drugs (we'll discuss some of them).

The neurotransmitter of the parasympathetic nervous system is acetylcholine. It is also stimulated by other cholinergic drugs, as we'll discuss. But let's talk a little more about these two systems:

The Sympathetic Nervous System

When activated, it promotes a "fight or flight" response. Activation thus leads to body arousal and energy generation, and inhibits digestion. It diverts blood flow away from the gastrointestinal (GI) tract and skin via vasoconstriction. Blood flow to the skeletal muscles and the lungs is enhanced (by as much as 1200% in the case of skeletal muscles). It dilates the bronchi and bronchioles of the lung, which allows for greater alveolar oxygen exchange.

It increases heart rate and the contractility of cardiac muscle cells, thereby providing the enhanced blood flow to skeletal muscles. It provides vasodilation for the coronary vessels of the heart, enabling the heart to beat faster and stronger. It dilates the pupils of the eyes and relaxes the ciliary muscle to the lens, allowing more light to enter the eye and improving far vision.

It constricts all the intestinal sphincters and the urinary sphincter, to keep them quiet. It inhibits peristalsis throughout the intestinal tract. Curiously, the sympathetic nervous system also takes over from the parasympathetic at the completion of the sex act and it stimulates actual orgasm. This may have a survival benefit for mammals in general, as they are most vulnerable to other predators when they are busy copulating. And, after all, we are all mammals.

There are two divisions of the sympathetic nervous system: alpha and beta. The alpha sympathetic nerves cause the blood vessels in the muscles to dilate and also the major arteries through the rest of the body to constrict, raising the blood pressure as needed to achieve maximum activity and strength while increasing flow to the muscles.

The beta sympathetic nerves go to the heart and lungs: stimulating the heart to beat faster and stronger, and stimulating the bronchioles to dilate and the lungs to breathe faster and deeper.

Drugs have been designed which stimulate, or block, one or the other of these two divisions, depending on the problem being treated.

The Parasympathetic Nervous System

When activated, it promotes a "rest and digest" response, blocking the alarm responses, calming of the nerves, returning the body to regular function, and enhancing digestion.

It dilates blood vessels leading to the GI tract, increasing blood flow needed for digestion. This is important following the consumption of food, due to the greater metabolic demands placed on the body by the gut.

The parasympathetic nervous system can also constrict the bronchiolar diameter when the need for oxygen has diminished. This protects the lungs and the body in general from toxic substances in the air: dusts, smoke, toxic chemicals, sand (when this becomes an over-reaction, this is what leads to asthma, as we'll discuss).

Dedicated cardiac branches of the Vagus nerve impart parasympathetic control of the heart, slowing the heart and diminishing the force of contraction to rest it as much as possible.

This nervous system causes constriction of the pupil and contraction of the ciliary muscle to the lens, allowing for closer vision, and for quiet work… making arrow points from flint, or perhaps, at other times in our human history, repairing fine watches. It stimulates salivary gland secretion, and accelerates peristalsis, so, in keeping with the rest and digest functions, appropriate PNS activity mediates digestion of food and indirectly, the absorption of nutrients.

The parasympathetic nervous system is also involved in the erection of the genitals, via the pelvic splanchnic nerves. It stimulates sexual arousal leading up to climax, then the sympathetic nervous system takes over.

Drugs that dilate the bronchioles

For treatment of asthma, some sympathetic stimulation drugs attach to beta receptors, which preferentially affect the lung bronchioles, relaxing them and counteracting the bronchospasm of asthma, which is an over-reaction, mediated by the inflammatory system of the body, to noxious particles in the air. This bronchodilation is the same process that occurs during an alarm reaction with sympathetic nervous system stimulation. These drugs include Alupent®, Ventolin®, Brethine®, and Maxair® (their generic names are not well-known). These medications can be aerosolized in an inhaler, with dose-controlled puffs.

Other bronchodilator drugs include theophylline and aminophylline. These two drugs are xanthines, in the same class as caffeine. They are also central nervous system stimulants (caffeine has the least bronchodilation effects).

Other widely-utilized drugs for treating asthma include steroids, like cortisone and prednisone, which counteract the inflammation in the bronchioles that occurs in this disease along with bronchoconstriction.

New asthma drugs include Singulair, which blocks the white cell release of histamine and leukotriene, that leads to bronchoconstriction. It is used to prevent an asthma attack. It does not work during an attack to stop it. This relatively new drug works well, with relatively few side effects.

The newest, most powerful drug is Xolair (omalizumab). It is a monoclonal antibody to IgE (immunoglobulin E, released during asthma attacks) and it works wonders in severe asthma (selectively blocks IgE release by the white cells in the lung tissue). Xolair must be given by subcutaneous injection, usually every two weeks. It is very expensive ($30,000-$40,000/year), and can cause anaphylactic reactions in some patients. Yet it often works better than anything else in severe cases of asthma, which can otherwise lead to status asthmaticus, a very intense attack of asthma that requires hospitalization and may be life-threatening.

Drugs for Gastrointestinal Problems

Not everyone has asthma or heart disease, but everyone has GI problems at one time or another. Dyspepsia is extremely common: stomach pain, cramping, fullness. About 15 percent of American adults have or will have a stomach or duodenal ulcer and 20 percent of American adults have GERD (gastroesophageal reflux), with burning sub-sternal pain radiating into the throat. Virtually everyone gets constipation or diarrhea at some time.

The relatively new wonder drugs for severe dyspepsia, ulcers, and GERD are the proton pump inhibitors. These powerful drugs inhibit the formation of hydrochloric acid in the parietal cells of the stomach. It is the hydrogen ion that makes it acid (H+…a single proton), which is formed in the stomach parietal cells in a pump-like mechanism.

The most popular proton pump inhibitors are omeprazole (Prilosec®), esomperasole (Nexium®), and a popular, relatively new combination of omeprazole and sodium bicarbonate known as Zegerid®. Prilosec and Zegrid are over-the-counter drugs, but Nexium still requires a prescription.

Also widely used drugs for these GI disturbances are the histamine two receptor antagonists (sometimes called H2 receptor blockers). Histamine 2, produced by the body, is required for the formation of stomach acid (HCL). Cimetadine (Tagamet®), developed in the 1970s, was the first blockbuster drug, earning more than $1 billion a year for its developers. Another very popular drug of this type is ranitidine (Zantac®).

H2 receptor blockers or proton pump inhibitors can be given IV to patients who are critically ill in the ICU to prevent stress ulcers. Hospital patients with serious conditions of all sorts are often placed on Tagamet or Prilosec. Both work well under these conditions to prevent GI bleeding in highly-stressed patients who are in shock, have a severe infection, or may be recovering from a severe automobile accident.

H pylori (a bacteria) is present in virtually all peptic ulcers and also needs to be treated, with antibiotics, usually a combination of two of them: metronidazole (Flagyl®) and doxycycline (Vibramycin®).

Diarrhea (dia-through, rhea-flow) is a common experience for most humans. Causes include toxic substances in the diet (food poisoning), drug reactions, viral infections (Norwalk virus), and, bacterial infections such as Staph, E coli, Salmonella.

Most cases of diarrhea are self-limiting over 1-2 days, and respond to the BRAT diet (bananas, rice, apple sauce, and tea, to calm the intestinal tract and replace lost electrolytes such as potassium and sodium).

Bacterial infectious diarrhea is more serious, presenting with fever, abdominal pain, and bloody diarrhea. Stool samples show white cells and cultures are often positive for Salmonella, Shigella, Camplylobacter, or Staphlococcus. Appropriate antibiotics are needed (often ciprofloxacin or doxycycline). Giardia diarrhea is caused by a parasite that shows up in the stool of campers. It responds to metronidazole (Flagyl®).

Most episodes of constipation are transient. Many are related to travel, a change in activities or diet, or prolonged immobilization after surgery or accidents. More severe forms can be due to certain drug reactions (iron replacement, narcotics, anticholinergics). Constipation is common in the elderly.

Conservative treatment is best, if possible, with increased fiber in the diet, and, if needed, bulk-forming agents such as psyllium fiber (Metamucil®), or konsyl fiber (Mitrolan®), which have no side effects. In severe constipation drug treatments are often prescribed by physicians. These include stimulant laxatives such as bisacodyl (Dulcolax®), cascara, or senna (Senakot®). Chronic use of these agents can cause dependency on them. Chronic senna use may actually damage the nerves to the colon, leading to intractable constipation, which often requires manual dis-impaction by a nurse!

Milder drugs for constipation are much preferred. Those which draw water into the colon include milk of magnesia, or polyethylene glycol (Miralax®). Colace® improves the penetration of water into the feces and causes increased bulk. Mineral oil lubricates the feces if the stools are especially compacted and dry and helps with elimination.

I hope this brief summary has been helpful. In my final installment next month I will discuss drugs for cardiovascular disease, antibiotics (along with antiviral and antifungal agents), and anti-inflammatory and immune suppressant drugs. For the first part of my series, visit my column page at www.acupuncturetoday.com.


Click here for more information about Bruce H. Robinson, MD, FACS, MSOM (Hon).

 

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