Heart rate conditions are known to be serious and at times life threatening in nature. Known commonly as unstable ventricular tachycardia and recurrent ventricular fibrillation, these conditions require suitable treatment for patients in a healthcare facility as well as out patients. However, by virtue of its mechanism of action and its known toxicity, it is only administered or recommended when other drugs and treatment options are ineffective. While it is considered as one of the most effective treatment options, its toxicity makes it necessary to exercise complete caution. Here is a look at the commonly reported side effects of amiodarone and methods to help mitigate and prevent adverse outcomes.

Overview of the drug and its mechanism of action

It is essential to understand more about the medication and its mechanism of action to be able to understand the possible outcomes. Labelled as a class III antiarrhythmic, it is recommended for the conditions mentioned above, which primarily relate to the heart rate. It belongs to the category of benzofuran derivative, and is sometimes prescribed for certain off label uses such as atrial fibrillation. This includes use for patients in an hospital and also patients recommended treatment at home. The prescription only drug requires to be administered only as per the exact prescribing instructions.

It is regarded to have a relatively high level of toxicity that may have an impact on multiple organs, with possible ADR (adverse drug reactions). Classification of ADR by the WHO is clear and adds more information – an ADR refers to the possible adverse outcomes when taken in normal dosages. This effectively means that the medication could trigger side effects even when taken in normal doses. It is therefore to be used only when the situation or the condition warrants its use. The possibility of side effects of amiodarone is higher among the elderly, and this is mainly because of the possible use of other medications and by extension, the drug interactions. It is regarded as an option with high efficacy for rhythm control but comes with the possibility of adverse reactions.

Mechanism of action of the medication

The drug works by blocking potassium currents that are responsible for the repolarization of the heart muscle. Consequently, the medication helps to extend the duration of the refractory period for the myocytes, and as a result the excitability of cardiac muscle significantly decreases. This in turn, helps to prevent and control abnormal heart rhythms.  The drug is regarded as different and unique when compared with other medications of the same category. This primarily because it is also known to have an impact on the functioning of calcium channels, sodium channels and beta-adrenergic receptors.

However, some of the side effects are attributed to these actions. For instance, hypotension, bradycardia are all possible adverse outcomes due to the above-mentioned additional actions. The drug is also known to increase the activity of certain receptors, that result in outcomes in certain organs of the body. Additionally, the drug also binds to the thyroid receptor, and this is one of the reasons for hypothyroidism that is attributed to the drug.

Commonly reported adverse effects of the drug

As mentioned above, the drug comes with the possibility of side effects. There are typically two different types of unwanted outcomes. The first category is the commonly reported adverse effects that are relatively common in occurrence, but with mild or moderate outcomes. In most of the drugs and medications, the common side effects typically resolve without the need for medical intervention. However, when the condition either persists or if it is intense in nature, it may be necessary to seek medical assistance. The other category – rare side effects – are, as the name suggests, rare in occurrence. However, these adverse effects are relatively serious in nature and may require medical intervention in some form. This may also include treatment at a healthcare facility or triaging in a hospital. Here is a look at the compilation of both categories of unwanted effects.

It is important to note that this compilation is not exhaustive in nature and only lists out known and reported effects. It is also necessary to note that for all medications and drugs, there is a clear difference in the manner in which undesirable effects impact different patients. For instance, certain patients may not experience any kinds of symptoms or effects whatsoever, while others may experience effects. This differs from patient to patient and depends on various conditions and factors.

#1 Relatively common, mild or moderate effects

As explained above, there are frequently occurring, mild or moderate effects. This includes low grade fever, possible cough and a light headed feeling among patients on the medication. Patients may also experience an abnormal tingling sensation in the limb extremities, such as the toes and the fingers. Other commonly reported symptoms include difficulty while walking, and a perceptible lack of control in the movements of the body. The individual may experience abnormal actions or movements that were not experienced or observed earlier. Breathing may sometimes be painful, and the patient may experience shaking or trembling of the hands. The individual is likely to also feel weak or experience sudden fatigue for no specific reason. Finally, there is also the possibility of patients experiencing some kind of sensitivity to sunlight, and its effects on exposed skin.

#2 Relatively rare or uncommon effects

The rare or uncommon effects that may be possibly experienced by patients on the medication include an abnormal cold feeling. The patient may experience blurred vision, with objects appearing unusual with a halo around the object in a blue-green color combination. The skin on the face, the neck and the arms of patients are likely to turn blue-gray in color as a result of medication. Similarly, patients on the drug may end up with dry eyes, and dry skin that appears puffed up. Discernible changes in patients include some form of nervous behavior, that may or may not be accompanied with a fast and racy heart beat that has an irregular rhythm.

Patients on the medication are also likely to experience pain in the crotch, that may or may not be accompanied by swelling in the scrotum. Effects of the drug include profuse sweating and possible swelling in the lower limb extremities – the feet. Visible effects include sensitivity to light that may affect the eyes, apart from sensitivity to heat that may affect the skin. Apart from fatigue, the patients may also experience a possible reduction in heart beat rate. Other effects include difficulty in falling asleep or the inability to experience deep slumber. In addition to the above, the patient may also end up with contrasting effects on weight – while some patients may end up with increase weight, some are known to lose weight.

#3 Effects that may not require specific treatment unless persistent or intense in nature

As outlined above, certain effects may not require any specific treatment unless it is persistent in nature or intense. For instance, individuals may experience certain effects during the initial phase of taking the medication in some form. As the body starts adjusting the mechanism of action of the drug, the effects resolve naturally. For instance, individuals may sometimes experience constipation when commencing the medication. Similarly, patients have reported possible headache and a clear loss of appetite when on the medication. Other effects include possible feelings of nausea and vomiting sensations. These undesirable effects are relatively common among a large section of the patients on the medication.

There are other unwanted effects that typically do not occur frequently. For instance, the patient may experience a bitter, metallic taste in the mouth when on the medication. A possible lack of interest in sex or reduced libido n males is also another possibility that may be experienced during the initial stages of taking the medication. The patient may also end up feeling abnormally warm, without indulging in any activity. Visible effects include a reddish appearance on the upper torso and face – the arms, the neck, the face and the upper portion of the chest.

General precautions and tips to manage and prevent side effects of amiodarone

While it may not be possible to fully prevent the manifestation of possible unwanted effects of drugs, it is possible to mitigate the effects or manage the effects. This is best achieved by identifying the symptoms and taking suitable precautions in time. It is advisable to consult a doctor periodically and go through necessary tests, wherever required to check for the manifestation of unwanted effects. Laboratory tests help understand or identify changes. Women who are either pregnant or planning a pregnancy are expected to seek specific medical advice regarding use of the medication. Similarly, patients who experience some kind of difficulty in breathing while on the medication are expected to report the same to the consulting doctor. Other symptoms that need to be reported include any form of unusual tightening in the chest, when on the medication.

Certain tell-tale symptoms indicate specific conditions and it is necessary to identify the conditions at the earliest. For instance, QT prolongation is the outcome of a difference in heart rhythm, and this is indicated through symptoms such as fainting. It is important to seek medical assistance at the earliest in such conditions. Other symptoms include a pounding heart beat, or fast, racy heart rate, apart from irregular heart beat that can be easily identified. Patients are also expected to report any change in the routine body functions, such as discoloration of urine or feces, and any unusual pain in the upper stomach.

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