Adalat® is metabolized up to 90% after absorption. It then reaches the liver where a large proportion is already metabolized and is no longer available for the actual effect. The proportion that can still be effective in the body is around 45-65%.
Interaction with other drugs
Medications that also lower blood pressure should only be combined with Adalat® in a controlled manner, as the blood pressure-lowering effect of both substances mutually enhances each other (this is even desirable in the case of high blood pressure that is difficult to adjust). The combination with certain substances used for anaesthesia should also be carried out with caution, as this would also lead to an intensified (in this case unintended) reduction in blood pressure. Nifedipine also has an effect on the metabolism of other drugs.
When Adalat® and quinidine are administered at the same time, it should be noted that the quinidine level initially drops when Adalat® is combined with quinidine, but then rises uncontrollably when the medication is discontinued. Adalat® also interferes with the metabolism of digoxin and theophillin, since all substances are split by the same enzyme in the liver. As a result, Adalat® increases the drug levels of the above-mentioned substances, which leads to an unintended increased effect (digoxin is used in heart failure therapy, theophillin in asthma therapy). The combination with the so-called NSAIDs (ASAIDs, ibuprofen, paracetamol), which are used to combat pain, reduce fever and inhibit inflammation, means that Adalat® is hindered in its effect, and cannot have as strong an antihypertensive effect as it should. The reason is that NSAIDs retain water and sodium in the vascular system, which results in an increase in blood pressure.
Adalat® should not be used if the patient also suffers from cardiac insufficiency or if unstable angina pectoris is known. Furthermore, it should not be used in patients with severe pathological heart changes, e.g. cardiomyopathy or rigidity of the heart valve (aortic valve stenosis). The reason is that Adalat® not only lowers blood pressure, but also causes a drop in blood pressure.
With such a drop, the damaged heart muscle cells cannot be supplied with sufficient blood, which further aggravates the heart disease. If the patient is known to have lowered blood pressure, Adalat® or comparable products should not be given either, as this would further lower the already low blood pressure. Adalat® and some other drugs in this group of substances can be taken in the 1st trimester of pregnancy, but are more likely to be second-choice drugs.
Due to the increased vasodilatation caused by Adalat® (nifedipine), fluid may leak into the tissue. This results in oedema, which is mainly deposited on the legs. In this case, the legs should be elevated and possibly also wrapped. In this case, the dose of the medication should also be reduced. It should also be considered whether to discontinue Adalat completely and use an alternative preparation.