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Page Synopsis: SSRI's and SSNRI's are often prescribed to CFS patients. There are many contraindications to taking Venlafaxine with other medicines

page 30 CFS > ALLOPATHIC MEDICINES > VENLAFAXINE

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Use of Venlafaxine should not be combined with * Ginkgo, * Metoprolol, * St John's Wort, * Zolpidem

 

Amantadine interacts with venlafaxin where the risk or severity of QTc prolongation can be increased when Venlafaxine is combined with Amantadine

 

QT prolongation is a measure of delayed ventricular repolarisation. Excessive QT prolongation can predispose the myocardium to the development of early after-depolarisations, which in turn can trigger re-entrant tachycardias such as TdP

From: Reviving the Broken Marionette: Treatments for CFS/ME and Fibromyalgia

 

Venlafaxine has a much stronger inhibitory effect on serotonin than norepinephrine. Large doses may also affect dopamine reuptake. Smaller dosages are often considered to only have serotonergic action. In any case for many patients venlafaxine is more helpful than the SSRIs and it sometimes helps depression refractory to all the other treatments. It can also be used to treat many different kinds of chronic pain.67 Desvenlafaxine is a metabolite of venlafaxine, which is only taken once a day.

 

Venlafaxine is fairly commonly used in both fibromyalgia and CFS/ME. Jay Goldstein uses a small dose of 37.5–75 mg twice a day, starting out with only 18.5 mg.68 He recommends trying SSRIs and bupropion first and venlafaxine only if these agents fail. According to him venlafaxine often works well in combination with risperidone, though this may carry the risk of serotonin syndrome.

 

One open and one double–blinded study have tried venlafaxine for fibromyalgia with promising results, but both were small and the results cannot be considered conclusive. Nonetheless both studies found significant improvement with venlafaxine.69,70 In the first one the improvement was found to be correlated with depression and anxiety; in the latter no such connection was found.

 

Venlafaxine can cause tachycardia and raise blood pressure, the latter of which could be beneficial for some. Nausea is more common than with the SSRIs. Other common side effects include e.g. psychiatric symptoms, sweating, hot flashes and visual disturbances. According to psychiatrist Eleanor Stein many CFS/ME patients tolerate the drug better if taken in small, frequent doses instead of slow release formulations.71

 

The treatment should never be discontinued abruptly, as venlafaxine is highly prone to causing withdrawal symptoms. Sometimes wean-ing off long–term use of the drug has to be done extremely slowly, over the course of several months. Venlafaxine has potential interactions with the same drugs as paroxetine. Azoles, macrolides and verapamil may elevate the blood levels of venlafaxine. Desvenlafaxine only potentially interacts with azoles.

 

Venlafaxine is available in the United States, the United Kingdom, Canada, Australia and many other markets. It is slightly more expensive than the SSRI drugs. In some countries normal tablets are no longer sold, only extended release formulations. Desvenlafaxine is only available in the United States and is more costly.

 

Drug Interactions

 

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

 

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

 

                                                    Contraindications ***

 

                                                    Using Venlafaxine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines. ***

 

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

 

* Ginkgo

* Metoprolol

* St John's Wort

* Zolpidem

 

Other Interactions

 

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

 

Other Medical Problems

 

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

 

* Bipolar disorder (mood disorder with mania and depression), or risk of or

* Bleeding problems or

* Glaucoma, angle-closure or

* Heart attack, recent or history of or

* Hypercholesterolemia (high cholesterol in the blood) or

* Hypertension (high blood pressure) or

* Hyponatremia (low sodium in the blood) or

* Interstitial lung disease, history of or

* Mania, history of or

* Seizures, history of or

* Stroke, history of or

* Tachycardia (fast heart rate)—Use with caution. May make these conditions worse.

 

* Kidney disease or

* Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

 

Dosing

 

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

 

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

 

* For oral dosage forms (extended-release capsules, extended-release tablets):

 * For depression:

  * Adults—At first, 75 milligrams (mg) per day, taken as one dose in the morning or evening. Some patients may need a starting dose of 37.5 mg per day, taken for 4 to 7 days. Your doctor may adjust your dose as needed. However, the dose is usually not more than 225 mg per day.

  * Children—Use and dose must be determined by your doctor.

 * For generalized anxiety disorder:

  * Adults—At first, 75 milligrams (mg) per day, taken as one dose in the morning or evening. Some patients may need a starting dose of 37.5 mg per day, taken for 4 to 7 days. Your doctor may adjust your dose as needed. However, the dose is usually not more than 225 mg per day.

  * Children—Use and dose must be determined by your doctor.

 * For panic disorder:

  * Adults—At first, 37.5 milligrams (mg) per day, taken for 7 days, taken as one dose in the morning or evening. Your doctor may adjust your dose as needed. However, the dose is usually not more than 225 mg per day.

  * Children—Use and dose must be determined by your doctor.

 * For social anxiety disorder:

  * Adults—75 milligrams (mg) per day, taken as one dose in the morning or evening.

  * Children—Use and dose must be determined by your doctor.

* For oral dosage form (tablets):

 * For depression:

  * Adults—At first, a total of 75 milligrams (mg) per day, divided and taken 2 or 3 times during the day. Your doctor may adjust your dose as needed. However, the dose is usually not more than 225 mg per day.

  * Children—Use and dose must be determined by your doctor.

 

Missed Dose

 

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

 

Storage

 

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

 

Keep out of the reach of children.

 

Do not keep outdated medicine or medicine no longer needed.

 

Ask your healthcare professional how you should dispose of any medicine you do not use.

 

Precautions

 

If you will be taking this medicine for a long time, it is very important that your doctor check you at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it.

 

Do not take venlafaxine with a monoamine oxidase (MAO) inhibitor (eg, isocarboxazid (Marplan®), phenelzine (Nardil®), selegiline (Eldepryl®), tranylcypromine (Parnate®)). Do not start taking venlafaxine during the 14 days after you stop a MAO inhibitor and wait 7 days after stopping venlafaxine before you start taking a MAO inhibitor. If you take them together or do not wait the proper amount of time, you may develop confusion, agitation, restlessness, stomach or intestinal symptoms, a sudden high body temperature, an extremely high blood pressure, or severe seizures.

 

Venlafaxine may cause a serious condition called serotonin syndrome if taken together with certain medicines. Do not use venlafaxine with buspirone (Buspar®), fentanyl (Abstral®, Duragesic®), linezolid (Zyvox®), lithium (Eskalith®, Lithobid®), methylene blue injection, tryptophan, St John's wort, amphetamines, or some pain or migraine medicines (eg, rizatriptan, sumatriptan, tramadol, Frova®, Imitrex®, Maxalt®, Relpax®, Ultram®, Zomig®). Check with your doctor first before taking any other medicines with venlafaxine.

 

This medicine may cause some teenagers and young adults to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. Some people may have trouble sleeping, get upset easily, have a big increase in energy, or start to act reckless. If you or your caregiver notice any of these unwanted effects, tell your doctor right away. Let the doctor know if you or anyone in your family has bipolar disorder (manic-depressive) or has tried to commit suicide.

 

Do not suddenly stop taking this medicine without checking first with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping it completely. This will decrease the chance of side effects, such as agitation, confusion, headache, irritability, numbness or tingling feeling, restlessness, trouble sleeping, or unusual drowsiness or weakness.

 

This medicine may cause hyponatremia (low sodium in the blood). This is more common in elderly patients, those who take diuretic medicines, or those who have a low amount of fluid in the body due to severe diarrhea or vomiting. Check with your doctor right away if you have a headache, trouble concentrating, memory problems, confusion, weakness, or feel unsteady when standing.

 

Venlafaxine may increase your risk for bleeding problems. Make sure your doctor knows if you are also using other medicines that thin the blood, including aspirin, NSAID pain or arthritis medicines (eg, diclofenac, ibuprofen, naproxen, Advil®, Aleve®, Celebrex®, Voltaren®), or warfarin (Coumadin®, Jantoven®).

 

Tell your doctor right away if you are having chest pain or discomfort, dry cough, fever, general feeling of tiredness or weakness, skin rash, or trouble breathing with this medicine. These might be symptoms of a serious lung problem, including interstitial lung disease and eosinophilic pneumonia.

 

Venlafaxine may cause some people to become drowsy or have blurred vision. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert or able to see clearly. It is best to avoid alcohol with venlafaxine.

 

Before you have any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine.

 

Check with your doctor right away if you have decreased interest in sexual intercourse, delayed or inability to have and orgasm in women, inability to have or keep an erection in men, or loss in sexual ability, desire, drive, or performance. These could be symptoms of sexual dysfunction.

 

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter OTC) medicines and herbal (eg, St. John's wort) or vitamin supplements.

 

Side Effects

 

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

 

Check with your doctor immediately if any of the following side effects occur:

 

More common

 

1. Change or problem with discharge of semen

2. decreased interest in sexual intercourse

3. inability to have or keep an erection

4. lack or loss of strength

5. loss in sexual ability, desire, drive, or performance

6. severe headache

7. sweating

 

Less common

 

1. Blurred vision

2. chest pain

3. delayed or inability to have an orgasm

4. fast or irregular heartbeat

5. mood or mental changes

6. ringing or buzzing in the ears

7. suicidal thoughts

 

Rare

 

1. Actions that are out of control

2. high fever

3. irritability

4. itching or skin rash

5. lightheadedness or fainting, especially when getting up suddenly from a sitting or lying position

6. menstrual changes

7. nervousness

8. problems with urinating or holding urine

9. seizures

10. severe muscle stiffness

11. talking, feeling, and acting with excitement that you cannot control

12. trouble breathing

13. unusually pale skin

 

 

Incidence not known

 

1. Agitation

2. bloody, black, or tarry stools

3. bloody stool or urine

4. dark urine

5. decreased frequency or amount of urine

6. diarrhea

7. drowsiness

8. fever

9. general feeling of tiredness or weakness

10. headache

11. increased thirst

12. light-colored stools

13. muscle cramps, spasms, or pain

14. nausea or vomiting

15. nosebleeds

16. overactive reflexes

17. poor coordination

18. red or purple spots on the skin

19. restlessness

20. shivering

21. stomach pain on the upper right side

22. swelling of the face, lower legs, ankles, hands, or fingers

23. trembling or shaking that is hard to control

24. twitching

25. unusual bruising

26. unusual tiredness or weakness

27. vomiting of blood or material that looks like coffee grounds

28. yellow eyes or skin

 

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

 

More common

 

1. Abnormal dreams

2. chills

3. constipation

4. decrease in sexual desire or ability

5. diarrhea

6. dry mouth

7. heartburn

8. increased sweating

9. loss of appetite

10. nausea

11. stomach pain or gas

12. stuffy or runny nose

13. tingling, burning, or prickly sensations

14. trouble sleeping

15. vomiting

16. weight loss

 

 

Less common

 

1. Change in taste

2. muscle tension

3. yawning

 

 

Incidence not known

 

1. Night sweats

 

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional

 

 

page 30 CFS > ALLOPATHIC MEDICINES > VENLAFAXINE

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