Second Generation Cephalosporins

Prototype drug is CEFUROXIME (IV) and CEFUROXIME AXETIL (oral). CEFOXITIN has good activity vs. anaerobes.

1. Expanded activity against gram negative bacilli. Still have excellent activity against gram positive (Staph. and Strep.) bacteria.

Activity for Gram negative bacteria

Neisseria sp. (some gonococci resistant)
H. influenzae (including some ampicillin-resistant strains)
Moraxella catarrhalis (some resistance esp. to cefaclor)
E. coli
Proteus mirabilis
Indole + Proteus (some strains resistant)
Morganella morganii (some strains resistant)
Klebsiella pneumoniae
Serratia sp. (many strains resistant)

2. Anaerobic infections - CEFOXITIN & CEFOTETAN only

Moderate activity against Bacteroides fragilis group.

Good activity for other Bacteroides sp., Peptostreptococcus, Fusobacterium, Clostridium sp

Uses
1. Community-acquired pneumonia - Cefuroxime is widely used for empiric therapy. Has activity vs. many ampicillin-resistant H. influenzae strains.
2. Skin and soft tissue infection
3. Urinary tract infections
4. Upper respiratory tract infections (otitis media, sinusitis). Some resistance to H.influenzae to cefaclor (20-30%).
5. Mixed aerobic & anaerobic infections - Cefoxitin & Cefotetan. Resistance to B.fragilis is increasing.
6. Surgical prophylaxis - Cefoxitin or cefotetan are widely used in cases where mixed aerobic & anaerobic infections may occur, esp. intra-abdominal, colorectal, and gynecologic operations. For cardiovascular and orthopedic procedures, cefuroxime and others may be used, but cefazolin is cheaper and appears to work well.

Neuron Basic Structure (How brain cells communicate)

• Synapse:A junction between the terminal button of an axon and the membrane of another neuron
• Terminal button(orbouton):The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron.
• Neurotransmitter:A chemical that is released by a terminal button; has an excitatory or inhibitory effect on another neuron.

Different types of Synapses
1-Axo-denrdritic 
2-Axo-axonal 
3-Axo-somatic

Chemical transmission in the CNS 

The CNS controls the main functions of the body through the action endogenous chemical substances known as “neurotransmitters”.
These neurotransmitters are stored in and secreted by neurons to “transmit”information to the postsynaptic sites producing either excitatoryor inhibitory responses.
Most centrally acting drugs exert their actions at the synaptic junctions by either affecting neurotransmitter synthesis, release, uptake, or by exerting direct agonistor antagonistaction on postsynaptic sites.

Codeine

Codeine is methyl morphine, with a methyl substitution on the phenolic hydroxyl group of morphine. It is more lipophilic than morphine and thus crosses the blood–brain barrier faster.

• classified as a simple, or mild analgesic, codeine is often used in low doses as an oral analgesic has a much better oral/parenteral absorption ratio than morphine.
• Effective for mild to moderate pain.
• Constipation occurs
• Dizziness may occur in ambulatory patients.
• More potent histamine-releasing action than does morphine.
• Should not be administered by IV injection.
• Extremely effective antitussive agent and is used therapeutically for suppressing cough.
• In contrast to morphine, codeine overdose can occasionally lead to the production of seizures.
• Seizures can be treated with barbiturates.
• Respiratory depression can be counteracted with Naloxone.
• orally, 30 mg of codeine is equi-analgesic to 600 mg of aspirin, however, the effects of the two are additive, and occasionally synergistic

Cough is a protective reflex which helps in expulsion of respiratory secretion or foreign particles which are irritant to respiratory
tract. Irritation to any part of respiratory tract starting from pharynx to lungs carried impulses by afferent fibres in vagus and
sympathetic nerve to the cough centre in the medulla oblongata. \

Cough may be dry (without sputum or unproductive) or productive (with sputum production). 

Classification for drugs used in cough.

I. Pharyngeal demulcents

Certain lozenges, linctus and cough drops containing glycerine, liquorice and syrups.

II. Expectorants

Sodium and potassium citrate
Sodium and potassium acetate 
Potassium iodide 
Ammonium chloride & carbonate
Acetylcysteine 
Bromhexine 
Guaiphenesin 

III. Antitussive

i. Opioids

Codeine (as linctus) Pholcodeine 

ii. Non-opioids

Noscapine
Dextromethorphan
Pipazethate 

iii. Antihistaminics

Chlorpheniramine 
Diphenhydramine 
Promethazine

Erdosteine is recently introduced mucolytic with unique protective functions for the respiratory tract. It is indicated in the treatment of acute and chronic airway diseases such as bronchitis, rhinitis, sinusitis, laryngopharyngitis and exacerbations of chronic bronchitis.

Oxytetracycline

Treats Oxytetracycline is a medicine used for treating a wide range of infections including infections of the lungs, urinary system, skin and eyes. It may also be used to treat sexually transmitted infections, infections caused by lice, rickettsial infections, cholera and plague. It is very occasionally used to treat leptospirosis, gas gangrene, and tetanus.

Characteristics of Opioid Receptors

mu₁

Agonists : morphine phenylpiperidines

Actions:  analgesia bradycardia sedation

mu₂

Agonists : morphine phenylpiperidines

Actions:  respiratory depression euphoria physical dependence  

delta

Actions:  analgesia-weak,  respiratory depression

kappa

Agonists: ketocyclazocine dynorphin nalbuphine butorphanol

Actions:  analgesia-weak respiratory depression sedation

Sigma

Agonists: pentazocine

Action: dysphoria -delerium hallucinations tachycardia hypertension

epsilon:

Agonists: endorphin

Actions: stress response acupuncture