Avoiding A ‘Missed Dose’
Assuring quality is important, right from sourcing of raw material to manufacturing and distribution of pharmaceutical products
By dr Ulhas Ganu
With the introduction of newer oral molecules, chemotherapy has changed a lot from what it used to be in the last century. That has come as a boon to patients as it offers them the advantage of taking medication at home. This, in turn, aids in both the replacement of aggressive cytotoxic chemotherapy, and avoiding the burden of having to spend time, money, and energy in getting admitted to a hospital. Unfortunately, the option of oral medication is not available for the treatment of all cancers. While patients, under the care and guidance of medical and paramedical staff in a hospital find it easier to keep track of their medication, once home, over 80 percent of patients have been reported to miss a few doses. The implications of missing proper medication can be serious, a fact not realized by most people. Some of the most common facts they fail to understand are:
1. Drug efficacy depends on the concentration of the drug, its active metabolites in the blood, or at the site of action.
2. Irregular consumption of drugs can affect the efficacy of treatment adversely. It has been estimated that thousands of Americans have avoidable heart attacks each year as a result of their negligence in taking the cholesterol-lowering medications prescribed by their doctors.
3. In the case of anti-diabetic drugs, a double dose taken mistakenly can exaggerate hypoglycemic response, leading to exhaustion and even to an emergency.
4. In skipping several doses of drugs, significant time is lost till therapeutic levels are reached again.
5. In the case of Tamoxifen that possesses a fairly long half-life and very long steady-state concentration, missing a dose occasionally may not matter much; however, it may mean a lot in the case of drugs like Imatinib as the target plasma concentration of the drug is missed, resulting in lesser efficacy. More missed doses may mean suboptimal treatment which may affect cure or control over the disease adversely.
6. Taking back-to-back doses of anticancer drugs with Narrow Therapeutic Index (NTI) may result in toxicity. NTI means that while only smaller increases in blood concentration of the drug can cause toxicity in the patient, small decreases in blood concentration can result in loss of efficacy. This implies that in the case of cancer patients, both missing a dose too often or taking the missed dose closer to the next one needs to be avoided.
Thus, the responsibility of taking medication on time during oral therapy at home rests solely with the patients and their close relatives. Old age, stress, forgetfulness, and the high cost of some medications are the frequent reasons patients give for missing doses. Here are a few steps to help patients avoid missing a dose:
1. Make a monthly table for the prescribed medications with mention of the medicine’s name, time and frequency of the dose. Ticking in the respective column immediately after taking a dose saves the anxiety of whether one has missed taking a dose of medicine. This also reduces the likelihood of taking a double dose.
2. Going through the doctor’s prescription once in a while during long term therapy may help, as the patient may have missed a point or two earlier.
3. In the case of long term therapy, purchasing medicines on time is important for timely medicine intake. In spite of the above precautions, one can still miss a dose or two occasionally. However, as discussed, missing doses frequently results in poor response to the treatment, defeating the very purpose of therapy.
Below is a list of remedial actions for an occasional missed dose; this does not apply for frequent misses:
1. Ask the doctor (in advance if possible) about what should be done in such cases. Clear advice from the doctor will protect the patient from undue anxiety later.
2. Look for the Patient Information Leaflet provided by the pharmaceutical company and the advice therein. Follow instructions as guided.
3. Ask a certified pharmacist, if the options mentioned above are not available. Planning well in advance will undoubtedly ensure the success of therapy
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