SSRIs and codeine – a poorly understood drug interaction

Codeine is a widely prescribed opioid agent most commonly used for the management of moderate to severe pain. Codeine is often prescribed in compound products such as those which contain a combination of paracetamol with codeine. Codeine is in fact relatively in active as an analgesic and largely relies upon metabolic conversion of codeine to small amounts of morphine for its clinical pain-relieving properties. This conversion is facilitated through metabolism of codeine via the cytochrome P450 2D6 isoenzyme. There is a degree of variability in the activity of the 2D6 enzyme, which may account for the variability in clinical response to codeine. From a pharmacodynamic viewpoint if an individual has a low activity of CYP 2D6 then the metabolic conversion of

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SIADH and anti-depressants

SIADH is a clinical syndrome that is relatively common and may result in significant hyponatremia. Fundamentally, SIADH is regarded as a condition whereby water excretion is compromised because of the body’s inability to suppress the abnormally elevated secretion of anti-diuretic hormone (ADH), an abnormality in the kidneys response to ADH, or the production of abnormal hormone-like compounds that produce effects similar to ADH (such as that observed in the context of some forms of malignant neoplasm). SIADH is also associated with a range of medications…………

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Amiodarone and the Thyroid

Amiodarone is a relatively widely prescribed anti-arrhythmic drug that is most commonly used in the management of refractory tachyarrhythmias such as Supraventricular Tachycardia (SVT) and Atrial Fibrillation (AF). Amiodarone is associated with a range of quite serious adverse effects, meaning that it is usually reserved for use in situations where other treatments are not appropriate.

As the name of the drugs implies, the amiodarone molecule includes a significant proportion of iodine and can exert a significant direct toxic affect upon the thyroid gland. In fact, the molar ratio is involved means that one 200 mg dose of amiodarone contains 6 mg of elemental iodine. This is significant if we consider that an average daily western diet often contains approximately 0.3 mg of iodine. The lipophilic characteristics of the amiodarone molecule mean that it is prone to concentrate preferentially in specific tissues, including the thyroid. Treatment with amiodarone…………

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