Clinical pharmacology in general practice: Bioavailability and therapeutic outcome

When physicians administer drugs to their patients.They do so in the expectation that the anticipated therapeutic effect will result.They are dismayed, therefore, when the patient either derives inadequate or no therapeutic benefit from the medication or worse still develops toxicity.Pharmacological principles state that effective drug therapy requires, not only that the appropriate drugs be given in adequate doses for adequate periods, but also that adequate concentraction of the drug must reach the site of action (blood) to be able to produce a reaponse.Bioavailability is the fraction of the admistered does which reaches the systemic circulation to be available to the receptors to produce a response and this is now reconized as one of the most important factors which determine the therapeutic outcome of many drugs.From the research done, the paper described two different done, the paper described two different aspects of bioavaility, which have to be taken into consideration.The first, fractional bioavailability, is due to the difference in the formulation of the same drug like Lariam and Mephaquin, as with mefloquine.The second phrmacokinetic availability, is due to difference in pharmacokinetics between sex, ethnic groups or diseases states like diarrhea and malaria. In addition, blood levels of different drugs like dapsone, chloroquine and propranolol can still differ (increased, descreases or delayed), .even in the same disease condition making off-hand prediction of response differcult.The use of clinical pharmacology to overcome this difficulty is discussed.

Effect of acute diarrhoea on the bioavailability of chloroquine in Myanmar subjects

Considering the possibility of altered bioavailability of during acute diarrhoea, there is a need to determine the therapeutic status of chloroquine as an antimalarial prophylactic during an attack of acute diarrhoea and to develop a reasonable basis for dose adjustment if necessary, in such clinical situations. Chloroquine 300 mg base was administered orally to 16 adult diarrhoeal patients from the Infectious Disease Hospital, Yangon and 12 healthy non-diarrhoeal volunteers. The drug serum levels at various time intervals up to 96 hours were analysed fluorometrically and the pharmacokinetic profile studied. Acute diarrhoea was found to decrease the rate, but did not alter the extent of absorption of chloroquine. Since the overall bioavailability of chloroquine remains unchanged, it was concluded that if there is no vomiting, dosage adjustment is not necessary in acute diarrhoea.

Utilization of hospital pharmacists in Yangon Division

A cross-sectional study was conducted in 13 hospitals in Yangon Division to explore the current situation with regard to the utilization of hospital pharmacists. In this study, the most commonly performed activities of hospital pharmacists were identified; the relationship between their perceptions of what they have learned and the frequency of performance of some selected activities analysed; and the attitudes of hospital pharmacists and other health team members on the role of pharmacists were being utilized mainly for drug store management. They were not being used apporiately for what they had been trained. Hospital managers and other close associates of hospital pharmacists in hospitals did not know the proper role of hospital pharmacists.

Acetaminophen (paracetamol) pharmacokinetics in contraceptive pill-using Myanmar women

Acetaminophen (paracetamol) pharmacokinetic study was made on a total of 16 healthy adult Myanmar women of reproductive age, half of whom were pretreated chronically for 6 month with an oral contraceptive steroid (OCS), namely, Combination 5. Single oral dose (930 mg) of acetaminophen showed similar extent of maximum plasma acetaminophen concentration in either group. However, the OCS causes significant effect (p<0.05) on plasma acetaminophen resulting in shortening of half-life by 21.6 per cent and augmentation of clearance by 5.9 per cent. The OCS affected predominantly the sulphate conjugation of acetaminophen. In regimen requiring repeated dosing, acetaminophen should be administered more frequently in the pill-users.

Hypotensive property of Plantago major Linn

50 per cent water-alcohol soluble extract of Plantago major Linn, from Rangoon, Kalaw and Taunggyi was tested for hypotensive action on anaesthetized normotensive dogs. Early trials with the water-alcohol soluble extract in a dose of 125 mg/kg given intravenously was found to produce a fall in arterial blood pressure of 20-40 mm Hg. Further fractionation of the extract was carried out and screened for hypotensivity activity. The fraction designated F -7 produced a fall in the arterial blood pressure which was sustained up to 1 hr.