Tranquillizers are drugs that reduce emotional instability, tension, fear, anxiety and induce sleep. They are also used in relieving stress, anxiety and irritability-Barbituric acid and its derivatives, known as barbiturates (veronal, amytal, nembutal, luminal) serve as good tranquillizers. Other tranquillizers which are not barbituric acid derivatives are chlordi-azepoxide, equanilmeprobamate, valium (diazepam), etc. Opium alkaloids such as morphine and codeine are powerful analgesics (reduce pain). Morphine is a very potent narcotic analgesic that is known to act on the central nervous system. Antimicrobials are substances that either kill microbes (microbiocidal) or prevent their growth (microbiostatic). These may be either sulpha drugs such as sulphapyridine, sulphadiazine, sulphaguanidine or antibiotics such as erythromycin, tetracycline, chloramphenicol which inhibit or arrest the growth of microbes.
The bactericidal and bacteriostatic antibiotics, respectively, are :
A. tetracycline and penicillin
B. penicillin and ofloxacin
C. penicillin and chloramphenicol
D. erythromycin and tetracycline
