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Doctors' Answers to "Frequently Asked Questions" - Drug Interactions (Page 1)
Drug Interaction - Calcium Channel
Blockers and Digoxin
Answer: They affect different channels. Digoxin inhibits Na-K ATPase and increases Calcium entry by a sodium-calcium flux exchange. The calcium channel blockers directly affect the calcium channels, but different calcium channel blockers are more specific for smooth muscle channels. Currently, it is thought that diltiazem, verapamil and bepridil act on cardiac muscle. Concurrent use of verapamil with digoxin can significantly elevate digoxin levels and most of the calcium channel blockers and digoxin both can affect the AV node of the heart concurrently, causing bradycaurdia.
Drug Interaction -
phenylpropanolamine and MAO inhibitors
Answer: Very Dramatic- Fast pulse, elevated blood pressure, flushing, and possible death with cardiovascular collapse. Dont try this.
Answer: There is no published data on multiple drug interaction. The best that can be done is to extrapolate the side effects and toxicities-- the actual interaction between four is not able to be predicted. However, phenteramine and pondimin should not be taken with Zoloft or any other SRI antidepressant. This is due to the simultaneous effect on serotonin in the body by both drugs. Depakoke's common side effects include nausea, sleepiness, vertigo(dizziness). Zoloft tends to produce constipation, headaches, drowsiness, and urinary hesitation. Phenteramine andpondimin tend to produce dry mouth, constipation, sleepiness-- so I would think sleepiness and constipation might be fairly severe. Again, Zoloft is strictly not to be used with the combination of pondimin and phenteramine.
Answer: In theory possibly, in practice no. In fact, we usually don't discontinue the drugs due to some patients developing rebound sensitivity to epinephrine post use of beta drugs. They may be decreased but rarely stopped.
Answer: I would recommend that your physician and pharmacist read the PDR. There is a strong relative contraindication between antidepressants and phen-fen or Redux. This is a combination that is potentially very problematic. Also, I would not be keen about ambien although there is not the warning seen with antidepressants and phen-fen.
Drug Interaction and Alcohol
Answer: Alcohol has several effects on a diabetic. 1. It is fermented sugar, and as such, is a major carbohydrate. You will need to decrease other carbohydrates with any alcohol ingestion. 2. It reduces inhibition and stimulates appetite so that it is difficult to keep on your diet. 3. It can decrease liver glucose release in some individuals. In general, a moderate intake-assuming you can keep your weight down is OK. However, few individuals can lose weight or keep it off with any alcohol intake.
Answer: Redux is fairly effective for weight loss. About 65% of patients experience weight loss which is very substantial. About 10-20% experience some loss. 10-20% don't seem to be helped. You will have dry mouth and constipation as the major side effects. Occasional patients have some other problems, but these are the common ones. There are reported risks of pulmonary hypertension and damage to heart valves. The exact risk is unclear, but both are serious and could lead to death or major cardiac surgery. As a consequence, I do not recommend these drugs for cosmetic loss, but only for patients with diabetes or elevated cholesterol who will definitely benefit from a loss.
Drug Interaction - Metrobamate /
Answer: Combining any antidepressant with Ritalin is tricky. There is no absolute contraindication, but I'd be reluctant especially in an on/off mode. It would be difficult to predict potential problems for something this complex.
Drug Interaction - Lipitor/
Answer: There is no interaction that I am aware of. There are potential interactions while taking erythromycin or equivalent drugs, digoxin, and some anti-fungals. I'm not aware of any interaction between these. You might have your physician call Parke-Davis scientific research. They will perform the research for free and usually come up with an answer. The number is: 800-223-0432.
Answer: Lanoxin is the brand name for digoxin, which is a common drug used for heart rhythms and occasionally for heart failure. This would be a common drug used in valve replacement patients since they tend to have irregular or fast heart beats. Zoloft is a serotonin reuptake inhibitor anti-depressant. This has little cardiac toxicity, but will generally be discontinued prior to heart surgery and restarted once the patient is stable. Larazepam is a benzodiazepine type of tranquilizer used to treat anxiety and other associated disorders. This is a fairly small dose. However, this drug should never be discontinued "cold turkey" since it can precipitate withdrawal symptoms.
Coumadin and Aspirin
Answer: Coumadin and aspirin are both used as anti-coagulants and are generally thought of as additive since they work on different aspects of the "clotting cascade". Coumadin works on different clotting factors made by the liver and aspirin on the platelets ability to clot. Measuring the TNR or PT will not take aspirins effect into account. This can be done by measuring "clotting time" a test rarely done unless a patient is persistently bleeding prior to transfusing platelets. The INR measures the anti-coagulant activity of coumadin and is thought to be more accurate that just using the PT measurement.
Answer: It certainly seems to be. I would spread these medications out in an attempt to ascertain which one is the culprit. I would also take her blood pressure and pulse during the spells to decide whether this is a blood pressure problem with the medications or a primarily neurologic side effect.
Drug Interaction - Synthroid/Redux
Answer: All the blood pressure pills can give trouble with erections. Some with ejaculation as well. Discuss this with your physician and try omitting one of the drugs for a couple of days and see if the problem is better. Than you can try another pill or take a drug holiday when you are going to have sex. This will depend on your blood pressure off the pill for short periods. The norvasc will usually clear in 30 hours and the atenolol may take 40-48 hours to clear.
Drug Interaction - anti-depressants
Answer: Amitriptyline's antidepressant effect usually takes two to three weeks to be effective. One dose will help sleep and increase drowsiness, but have little effect on depression. All of the SRI drugs have specific warnings against concomitant use of these two classes together. While I have seen occasional patients use this combination, it cannot be recommended.
Pondimin and Phenteramine
Answer: Pondimin (fenfluramine hydrochloride) is an anorectic drug, as is phenteramine. Fenfluramine is a sympathomimetic amine which is in the same class as amphetamines, except they don't seem to produce the central nervous excitement as amphetamines, nor the addiction. The combination is used to treat weight loss and is effective about 75% of the time. Common side effects include drowsiness, dry mouth, constipation and occasional nausea. Few patients have trouble with the side effects. There is a reported association with pulmonary hypertension. This is a potentially fatal disease. Whether these drugs have anything to do with this problem is currently unclear but under intense research.
Drug Interaction - Coumadin/Lanoxin
Answer: Coumadin is a blood thinner used in multiple medical situations. I am not aware of any drug interaction between Lanoxin and Coumadin, although Coumadin has interactions with many drugs. The palpitations may indicate high or low levels of Lanoxin.
Drug Interaction -
Answer: About the only antibiotic that is a problem is Flagyl (metronidazole). The chemical structure of metronidazole is similar to Antabuse. This is a drug used to make alcoholic dependent patients ill when they ingest alcohol. Taking Flagyl with alcohol will have this similar effect.
Answer: Common side effects of Augmentin are GI intolerance. This is usually not a true allergic reaction, but instead, a local effect. The joint pain may be another story. TMP/DS is a combination of trimethoprin and sulfa. Sulfa drugs are notorious for causing allergic reactions and trimethoprin much less so. It sounds like you may be allergic to the sulfa and probably not to the Augmentin.
Drug Interaction - Zoloft/Midrin
Answer: Midrin is a sympathomimetic amine used to constrict arterioles. While I'm not aware of any specific contraindication, I'd be leery of combining the two. I'd stick to Tylenol with Codeine while on Zoloft. Also work on preventive measures like Beta-blockers to minimize the number and severity of your migraines. Other medications like Imitrex, etc., would also be possibly risky.
Answer: Im not aware of concurrent studies of the two drugs. Im personally not a fan of using other drugs in concurrence with the Fen-Fen type of drugs until further experience is gained. The FDA collects the Adverse Drug Reactions, which are available. You might want to contact them for specific cases. Be advised that filing of and ADR does not necessarily imply casualty.
Drug Interaction with Propulsid
Answer: Propulsid should be avoided in conjunction with macroglide antibiotics (erythromycin, etc.), ketoconazole (an antifungal antibiotic), and similar antifungals. Taking this drug with cimetidine has been reported to elevate serum levels also (not with other H2 blockers). I know of no specific contraindication with Ultram or Zocor.
Answer: There is no obvious problem with this combination. I would space out the antacid though.
Answer: Your physician is probably right about the synergistic effect. Valium and similar drugs seem to have the same effect on Irritable Bowel Syndrome. We try to minimize the amount due to the addictive potential of benzodiazepines (like Valium). I would take it when your IBS flares up and try not to take it on a daily basis.
Manic Depression and Lithium
Answer: This combination of drugs is pretty common with the diagnosis that you have provided. Lithium is a drug that can be very toxic. Consequently, normal use dictates an occasional check of blood levels, blood sodium levels and thyroid levels. This is the minimum monitoring needed for this drug. The other two need less blood work monitoring.
Answer: It sounds like the cause of the stroke was elevated blood pressure. Three of the drugs listed are for blood pressure. Ritalin is the only unusual drug listed here. This can elevate blood pressure and is an odd combination with the others.
Answer: Each drug has a separate list of potential drug interactions. Certain specific drugs like heparin, coumadin, and certain antibiotics have lists of possible interactions. The best overall source is a good pharmacy text like Goodman and Gilman (The Pharmacological Basis of Therapeutics) or the Physicians Desk Reference.
Answer: Elavil has a different effect on sleep than the SRIs do. In particular, it increases Stage 4 sleep, necessary for deep muscle relaxation. SRIs do not produce this and may decrease Stage 4 sleep. This is the best current treatment for fybromyalgia - to increase muscle relaxation by increasing stage 4 sleep.
Answer: Non-steroidal anti-inflammatories and aspirin should not usually be taken with Coumadin since they will increase the risk of bleeding and block the ability of platelets to clot with any blood. They do not change the effect of Coumadin but, affect the coagulation cascade at a different point increasing the difficulty in clotting. They also are common causes of bleeding from the GI tract.
Answer: I wouldnt expect any, but some women experience mood alteration on hormone treatment, with or without the other drugs.
Answer: Redux(dexfenfluramine hydrochloride) and phenteramine/fenfluramine are appetite suppressants. They have been used for the past several years to aid in weight reduction after publication in JAMA of an article and subsequent follow-up articles detailing the weight loss potential of this drug with very few side effects. These drugs are indicated for weight loss necessary to correct or improve the treatment of hypertension, diabetes mellitus, elevated cholesterol, with a body mass index of 27 or no risk factors and a body mass index of 30. Body mass index is arrived at by dividing your weight in pounds by your height in inches. These drugs should not be taken with MAO inhibitors, Imitrex (used for migraines), while pregnant, with anti-depressant drugs of any variety, especially SRI inhibitors, if glaucoma is present, or if under 18. Usual dosage of Redux is 15 mg twice a day. Ionomin's dosage is 15 mg once a day, and 30 mg if the individual is unresponsive. Pondomin's dosage is 15 mg three times a day, but this can be increased to 30 mg three times a day (t.i.d.). These drug regimens do not appear to be addictive currently. The biggest risk appears to be pulmonary hypertension. This is increased with taking these drugs and can lead to death, so it is not taken lightly. This appears to be an unusual but serious side effect. Common side effects for most patients are dry mouth, constipation, diarrhea, and drowsiness.
I have had a lot of success with these drugs. Redux is easier to take, but may not be as effective. Ionomin and Pondimin are a little more effective, but less convenient and slightly more costly. The weight loss tends to return after the medicines are discontinued. They are usually effective in about 80% of my patients. I have major concerns about pulmonary hypertension and I do not prescribe these drugs until all the risks are laid out and only for high risk patients.
I'm not aware of any special risks with Effexor, Lithium, or Olenzapine. However, I usually do not use these drugs with any other CNS drugs due to the interactive problems.
Answer: Erythromycin is not related to penicillin or amoxicillin, being a macroglide. However, it can change the levels of theophylline and the child needs their level watched closely or their dose decreased.
Zoloft and doxepin interactions
Answer: Zoloft and doxepin(or any tricyclic) are hard to mix. The results tend to be variable and hard to predict. There clearly was an interactive problem with one of your medications. It is hard to tell whether zoloft or the depakote or the risperdal caused the problems. In any case, I'd avoid it-or try eliminating one medication at a time with doxepin. It seems like forgetting the doxepin is the best plan.
Answer: This is a pretty standard list for a diabetic with heart failure or hypertension. There can be interactions particularly concerning potassium and renal function. However, monitoring with blood tests will detect these problems. That would be the major consideration.
Answer: This is a combination to be avoided. This is because both medications work on the serotonin levels in the brain. One of the relative contraindications is SRI anti-depressants with phentermine or equivalent.
Answer: Redux (dexfenfluramine hydrochloride) and phenteramine/fenfluramine are appetite suppressants. They have been used for the past several years to aid in weight reduction after publication in JAMA of an article and subsequent follow, up articles detailing the weight loss potential of this drug, with very few side effects. These drugs are indicated for weight loss necessary to correct or improve the treatment of hypertension, diabetes mellitus, elevated cholesterol, with a body mass index of 27 or no risk factors and a body mass index of 30. Body mass index is arrived at by dividing your weight in pounds by your height in inches. These drugs should not be taken with MAO inhibitors, Imitrex (used for migraines), while pregnant, with anti-depressant drugs of any variety, especially SRI inhibitors, if glaucoma is present, or if under 18. Usual dosage of Redux is 15 mg twice a day. Ionomin's dosage is 15 mg once a day, 30 mg if the individual is unresponsive. Pondomin's dosage is 15 mg three times a day, but this can be increased to 30 mg three times a day. These drug regimens do not appear to be addictive currently. The biggest risk appears to be pulmonary hypertension. This is increased with taking these drugs and can lead to death, so it is not taken lightly. This appears to be an unusual but serious side effect. Common side effects for most patients are dry mouth, constipation, diarrhea, and drowsiness.
I have had a lot of success with these drugs. Redux is easier to take, but may not be as effective. Ionomin and Pondimin are a little more effective, but less convenient and slightly more costly. The weight loss tends to return after the medicines are discontinued. But they are usually effective in about 80% of my patients. I have major concerns about pulmonary hypertension and I do not prescribe these drugs until all the risks are laid out and only for high risk patients. Regarding Wellbutrin, I would not mix these combinations. Wellbutrin is a complete separate class of anti-depressants, but one is not to mix the SRI anti-depressants with phen/fen.
Answer: Primacor is a relatively new drug used in heart failure. It is a peripheral vasodilator as well as an inotropic agent (makes the heart beat stronger). It should not be used in patients with severe aortic or pulmonary valvular disease and can aggravate problems in patients with cardiac outflow obstructions. Use with diuretics like lasix should be performed with caution since over diuresis can decrease cardiac filling. In general practice, this is not usually a problem and these two drugs are commonly used together.
Lopressor and Phendimetrazine
Answer: Lopressor is a trade name for a medication known as metoprolol tartrate, and is in the class of medications known as "Beta blockers". Its uses include but are not limited to patients suffering from coronary artery disease, to hypertension, to anxiety conditions. Phendimetrazine is a combination medication and contains premarin and meprobonate. Both premarin as well as meprobonate can have depression effects, and lopressor can as well. Thus, if you are on both of these medications, keep in touch with your physician regularly and be sure to make them aware of any "blue moods" or depressed feelings you may be experiencing. Both of these medications can have heart effects as well, although these are less commonly seen in patients taking phendimetrazine. Although the intent of taking lopressor is to have a heart effect, these effects can be magnified or suppressed by the phendimetrazine. Your symptoms, and your tolerance of these medications will help your physician decide as to whether this medication regimen is benefiting you, without undue side effects.
Answer: That certainly is an imposing list of medications. First, predicting drug interactions only works with two drugs. There are geometrically rising interaction possibilities as the number of drugs rises. Consequently, there is no clear way to predict the interactions of three or four drugs short of giving them to a patient. I will say that there are some possibilities in your list. First, Uriset, Lomotil , Darvocet and Naprosyn all potentially effect the motility of the colon. Darvocet, Xanax and Lomotil all potentially have CNS effects. Having said this I doubt any serious interactions if the doses are kept limited.
Answer: Esgic plus is a combination of butabital, acetaminophen, and caffeine. The difference between esgic and esgic plus is merely extra tylenol. As such, Esgic is the same formulation as Fiorninal and would have the same side effects.
Tamoxifen & Zantac
Answer: Not aware of this, and it is not mentioned in the PDR. You might contact Zeneca 302-886-8000 and ask the manufacturer.
Claritin & Penicillin
Answer: Claritin is the brand name of the generic medication loratadine, and is used for its antihistamine effects in the treatment of allergies. Any medication that can effect liver metabolism of this medication can alter its blood level. Penicillin is cleared predominantly by the kidney and the Physicians Desk Reference does not list penicillin as a medication to be avoided in patients on claritin. However, whenever you are taking medications, in particular multiple medications, follow up with your physician on a regular basis is important, so as to assess the response you are having from the therapy, as well as to determine if any drug interactions or side effects are occurring.
Answer: Adipex is the brand name of a medication known as phentermine, and has been used in the treatment of obesity as a part of a weight loss regimen. Firstly, recent data published in several sources have reported the risks of taking this medication, particularly when it is used in conjunction with other weight loss pills. For this reason, you should see your health care provider to discuss whether you should stay on this medication, or discontinue it. With respect to light headedness, there are many possible causes for this symptom. The initial evaluation of dizziness involves a detailed history. Does the dizziness occur when standing, for example, upon getting out of bed in the morning, or out of chair. Does the dizziness come on with meals, or with rapid position changes of any kind, or at certain times of day? Is there any relationship between the time of taking medications and the time you experience dizziness? Are there any other medical conditions you may have that can also cause dizziness? A thorough physical examination is important in evaluating the patient who complains of dizziness, as well. The Physicians Desk Reference does list low blood pressure as a possible side effect of this medication. As you are already on another drug to lower your blood pressure, your symptoms may be due to excessive lowering of your blood pressure. However, bear in mind that there are many possible causes for dizziness. You should make your health care provider aware of your symptoms. He or she knows your medical history and conditions best, and can evaluate you for what may be causing the dizziness, with a thorough history and physical, as well as any additional testing that he or she feels is necessary.
Ziac & Premarin
Answer: Ziac is a combination of a beta blocker and a diuretic. Beta blockers are notorious for causing nausea. Whether the lightheadedness is or not is problematic. I'd discuss this with your doctor and try a short holiday(under supervision).
Maxzide & Cozar
Answer: Most certainly-potassium sparing drugs should be closely monitored with the class of ACE inhibitors to avoid hyperkalemia.
Contin & Ativan
Answer: Both MS Contin and Ativan are addicting and in somewhat different ways. There will be additive sedation and lethargy with the combination of these two drugs-depending somewhat on how much tolerance you have with the MS Contin. Other than addiction, there does not appear to be long term side effects of taking morphine continuously.
Paxil & Serzone
Answer: On the package warning/labeling it specifically warns about weight loss. In practice, about 75% of my patients gain weight on paxil or Serzone-about 10-15% lose weight. You'll need a different antidepressant than the SRI class. Some have better luck with St. John's Wort;but, it doesn't seem as effective on depression.
Atenolol & Lescol
Answer: None that I am aware of.
Answer: Of the medications you are taking lanoxin is notorious for GI toxicity. This can be simply checked with a drug level -if not particularly elevated probably not the cause. Aspirin can also cause gastritis. Lastly, diabetes mellitus can affect the nerves responsible for the motility of the GI trct causing these same symptoms.
Zoloft & Zyban
Answer: None that I'm aware of;but, Zyban has only been available a short time-come back in a year for a recap.
Mom's Multiple Medications
Answer: Geriatric patients who have multiple medical problems and are on multiple medications require a high degree of insight to figure out the best options. This can be done by a physician who has seen her before, a geriatrician or an internist. The setting of the nursing home is not the best option for diagnosis and treatment. A physicians office would be better. Did she have an Internist during her hospitalization? Check with them.
Cipro, Desogen, & Albuterol
Answer: Shouldn't be any reaction here.
Lotension, Lanoxin, Lopressor,
Dyazide, & Coumadin
Answer: Possibly, but, he must have pretty significant coronary disease to be on this combination. Hard to tell how much is drugs and how much his original condition. Lanoxin and lopressor would be the most likely candidates if it is the drug combo. Has he been monitored when he has these symptoms? This would give you the answer to the cause(that is cardiac or non-cardiac). Also, what is his blood pressure? I suspect fairly low with this combination.
Lanoxin & Lasix
Answer: No direct interaction. A lowering of potassium(caused by lasix) could
potentiate arrthymias due to lanoxin. Otherwise, nothing I'm aware of.
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