Interaction of muscle relaxant effect of gallamine with ethanol: in vivo mammalian model.

Ethanol produces alterations in muscular contraction and neuromuscular function both in vitro and in vivo in mammalian and amphibian tissues in dose dependent manner. It is not very well known whether gallamine, a commonly used muscle relaxant produces any interaction with ethanol. Hence in the present study, interactions of ethanol with gallamine are undertaken using rabbit head drop method. The latency time to produce head drop by gallamine in the absence and presence of ethanol (dose which produce ataxia) was insignificantly different (P > 0.05). It may be due to fact that ataxic dose may not be affecting neuromuscular transmission a significant manner. It, therefore, does not warrant to adjust the dose of gallamine in alcoholic persons.

Protective effect of fluoroquinolones on dapsone induced erythrolysis.

Various quinolones have varied effects on the preservative activity of blood cells. Nalidixic acid causes hemolysis in G-6PD deficient patients where as ofloxacin has been found to possess preservative action of WBCs. The present study was undertaken to see the effect of various fluoroquinolones on RBC membrane. The effect of quinolones like ciprofloxacin, ofloxacin and norfloxacin and nalidixic acid in the dose of 5 micrograms/ml was studied on dapsone induced, in vitro hemolysis of rabbit RBC, using the osmotic fragility test. The mean corpusular fragility (MCF) with various agents were as follows: (mean +/- SE) saline; 5.23 +/- 0.21; dapsone, 6.57 +/- 0.23; ofloxacin, 3.81 +/- 0.13; ofloxacin and dapsone, 5.13 +/- 0.11; nalidixic acid, 6.28 +/- 0.16; nalidixic acid and dapsone, 6.65 +/- 0.13; ciprofloxacin, 3.52 +/- 0.22; ciprofloxacin and dapsone, 4.80 +/- 0.2; norfloxacin, 1.97 +/- 0.23; norfloxacin and dapsone, 4.27 +/- 0.20. The MCF data and shift of the osmotic fragility curves (to the left) show that dapsone induced erythrolysis is significantly protected by ciprofloxacin, ofloxacin and norfloxacin but not by nalidixic acid.

Rational drug therapy as evaluated from student's clinical case reports.

210 prescriptions selected by students from Sucheta Kriplani and R.M.L. Hospitals were subjected to audit prescription in a group discussion with faculty members in the Department of Pharmacology of Lady Hardinge Medical College, New Delhi. It was observed that inadequate treatment was prescribed to the patients suffering from common diseases like amoebiasis, tuberculosis and typhoid fever. Indiscriminate use of antibiotics, antihistaminics, NSAID, vitamins and haematinics was a common observation.

Aspirin by virtue of its acidic property may act as teratogen in early chick embryo.

Aspirin (acetylsalicyclic acid) was dissolved either in normal saline or in phosphate buffer and was used in two doses to find out whether teratogenic potential of aspirin in chick blastoderm model is due to its acidic property or due to drug action. Drug was injected sub-blastodermally by window technique in fresh embryonated eggs after 17 hours of incubation at 39 degrees C. Eggs were re-incubated and harvested at 40 hours. Normal development of embryos was seen with normal saline and percentage of normal embryos with 30 micrograms (pH-3.19) and 120 micrograms (pH-2.64) aspirin was 31.7 and 4.9 respectively. Buffer produced 80.8% normal embryos and buffered 30 micrograms (pH-6.87) and 120 micrograms (pH-6.69) aspirin produced 67.7% and 30.8% normal embryos respectively. Changing the pH of aspirin to near neutral decreased the defect induced by aspirin but a significant effect of aspirin was observed at higher dose which could be independent of pH action.

Interactions of neuromuscular blocking agents with ethanol.

Alcohol produces contraction of isolated frog rectus abdominis muscle in a dose dependent manner. In the present study interactions of pancuronium, gallamine and succinylcholine with ethanol have been studied. Pancuronium and gallamine behaved in a non-competitive manner with ethanol. The PD'2 values of pancuronium and gallamine were almost similar. Succinylcholine produced persistent contraction of the muscle which remained unaltered on addition of ethanol. The findings with pancuronium and gallamine suggest that ethanol may be acting through metactoid nicotinic receptors or by the release of acetylcholine like substance.

Mechanism of aspirin induced neural tube defect in chick embryo.

The effect of acetyl salicylic acid (aspirin) on neural tube development in chick embryo was studied, using the chick embryo blastoderm model. Aspirin was injected in four different doses sub-blastodermally into fresh embryonated eggs. The role of PGE1 and PGE2 alpha in the defect induced by aspirin on neural tube development in chick embryo was studied. PGE1 (5 micrograms) given after aspirin (30 micrograms) treatment was found to produce greater defect in development. All the four doses of aspirin used (i.e., 6, 30, 60 and 120 micrograms/embryo) produced significant changes (P < 0.01) in the neural tube development of chick embryo. Pre-treatment with PGE1 did not modify the defect induced by aspirin, whereas pre-treatment with PGF2 alpha prevented neural tube defects induced by aspirin. It appears that aspirin (in the doses used) affects neural tube formation by decreasing PGF2 alpha synthesis in chick embryo blastoderm.

On mechanism of action of ethanol-induced contraction of frog rectus abdominis.

Ethanol in low doses (0.5 to 4 M) causes contraction of isolated frog rectus abdominis muscle. Higher concentration did not produce any further increase in maximum response. Pretreatment with dantrolene produced partial but equal inhibition of acetylcholine (Ach) induced as well as ethanol-induced contraction in equieffective doses. Pretreatment with pancuronium produced right and downward shift of ethanol induced contraction. Pretreatment with succinylcholine produced persistent contraction of tissue and this response remained unaffected on subsequent treatment with Ach as well as ethanol. Pretreatment with hemicholinium abolished ethanol induced contraction, although tissue remained viable as confirmed on addition of Ach. The contraction induced by ethanol decreased on pretreatment with dantrolene as well as in Ca2+ free ringer. The results indicate that ethanol induced contraction may be due to release of Ach or Ach like neurotransmitter at neuromuscular junction and calcium acts as mediator to produce these effects.

Pharmacodynamic bioequivalence: evaluation of different brands of terfenadine hydrochloride.

Terfenadine is a selective histamine H1 receptor antagonist which binds preferentially to peripheral receptors in vivo and is devoid of central nervous system depressant activity and thus has an improved adverse effect profile (1). Hence, terfenadine may be considered to be a first line agent in the treatment of allergic rhinitis and chronic urticaria. In man terfenadine is rapidly absorbed following a single oral dose and a peak terfenadine plasma concentration is reached within 1-2 hr after the drug administration (2). The present study was carried out to compare the bioequivalence of two terfenadine hydrochloride preparations marketed by Kopran Chem. Co. and Marrel Dow U.K. (Triludan) by evaluating their ability to inhibit the skin reaction to intradermally injected histamine (3).

Effect of variations in temperature of injected saline on early development of chick embryo.

Development of chick embryo is sensitive to the incubation temperature and increase or decrease in incubation temperature produces defect in development but the effect of drug solution injected at variable temperatures on developing chick embryo has not been established so far. Fresh embryonated eggs were incubated and saline was administered at various temperatures after 17 hr of incubation. Embryos were harvested to see the effect of temperature variations of injected saline on neural tube formation. Normal neural tube development was seen only at 37 degrees C, hot or cold saline produced maldevelopment of neural tube. Thus it is concluded that any solution or drug which needs to be injected should ideally be used at 37 degrees C, as temperature lower or higher than that may vitiate the results.

Influence of clonidine, methyldopa and propranolol on acute toxicity of fenitrothion in mice.

The effect of pretreatment with clonidine, methyldopa and propranolol, and of atropine was studied in mice on acute toxicity of fenitrothion, the active ingredient of TIK-20. Atropine significantly decreased and propranolol somewhat decreased the fenitrothion induced death in mice. Clonidine and methyldopa somewhat increased the percentage mortality due to fenitrothion.