Flucloxacillin, important even now for its resistance to beta-lactamases produced by bacteria such as Staphylococcus species. It is still no match for MRSA (Methicillin Resistant Staphylococcus aureus).

The last in the line of true penicillins were the antipseudomonal penicillins, such as ticarcillin, useful for their activity against Gram-negative bacteria

Different Systems of the CNS & their functions

These systems are pathways formed of specific parts of the brain and the neurons connecting them. 

They include:
1.The pyramidal system 
2.The extrapyramidal system 
3.The limbic system 
4.The reticular formation 
5.The tuberohypophyseal system

The pyramidal system: 

It originates from the motor area of the cerebral cortex and passes through the spinal cord, therefore it is also known as the “corticospinaltract”. 
It is responsible for the regulation of the fine voluntary movements.

The extrapyramidal system: 

It also controls the motor functionbut involves areas other than the corticospinal tract. 
It is involved in the regulation of gross voluntary movements, thus it complements the function of the pyramidal system. 

The “basal ganglia” constitute an essential part of this system. 

Degenerative changes in the pathway running from the “substantianigra”to the “corpus striatum”(or nigrostriatal pathway) may cause tremors and muscle rigidity characteristic of “Parkinson’s disease”.

The limbic system: 

The major parts of this system are: the hypothalamus, the basal ganglia, the hippocampus(responsible for short term memory), and some cortical areas. 

The limbic system is involved in the control of “behavior”& “emotions”.

The reticular formation:

It is composed of interlacing fibers and nerve cells that run in all directions beginning from the upper part of the spinal cord and extending upwards. 
It is important in the control of “consciousness” and “wakefulness”.

The tuberohypophyseal system: 

It is a group of short neurons running from the hypothalamusto the hypophysis(pituitary gland) regulating its secretions.
 

Benzodiazepines
All metabolites are active sedatives except the final glucuronide product. Elimination half-life varies a great deal from drug to drug.

?-Hydroxylation is a rapid route of metabolism that is unique to triazolam, midazolam, and alprazolam.
This accounts for the very rapid metabolism and short sedative actions of these drugs.

Pharmacological effects of benzodiazepines

- Antianxiety.
- Sedation.
- Anticonvulsant (including drug-induced convulsions).
- Amnesia, especially drugs like triazolam.
- Relax skeletal muscle (act on CNS polysynaptic pathways).

Indications

- IV sedation, (e.g., midazolam, diazepam, lorazepam).
- Antianxiety.
- Sleep induction.
- Anticonvulsant (e.g., diazepam, clonazepam).
- Panic disorders.
- Muscle relaxation.


Adverse effects

- Ataxia, confusion.
- Excessive sedation.
- Amnesia (not a desired effect with daytime sedation).
- Altered sleep patterns (increase stage 2 and decrease stage 4 sleep).

Adverse effects 

Nitrates 
– Headache, hypotension, dizziness, lightheadedness, tachycardia, palpitations 

Beta-adrenergic blocking agents
– hypotension, bradycardia, bronchospasm, congestive heart failure 

Calcium channel blockers 
– hypotension, dizziness, lightheadedness, weakness, peripheral edema, headache, congestive heart failure, pulmonary edema, nausea, and constipation 

Drugs that increase effects of Antianginal drugs 
• Antihypertensive 
• Diuretics 
• Phenothiazine antipsychotic agents
• Cimetidine 
• Digoxin 

Drugs that decrease effects of Antianginal
• Adrenergic drugs - epinephrine 
• Anticholinergic 
• Calcium salts 
• Phenobarbital, Phenytoin

Adjunctive Antianginal Drugs

In addition to antianginal drugs, several other drugs may be used to control risk factors and prevent progression of myocardial ischemia to myocardial infarction and sudden cardiac death.

These may include:
• Aspirin. This drug has become the standard of care because of its antiplatelet (ie, antithrombotic) effects. Recommended doses vary from 81 mg daily to 325 mg daily or every other day; apparently all doses are beneficial in reducing the possibility of myocardial reinfarction, stroke, and death. Clopidogrel 75 mg/day,
Is an acceptable alternative for individuals with aspirin allergy.

• Antilipemics. These drugs may be needed by clients who are unable to lower serum cholesterol levels sufficiently with a low-fat diet. Lovastatin or a related “statin” is often used. The goal is usually to reduce the serum cholesterol level below 200 mg/dL and lowdensitylipoprotein cholesterol to below 
130 mg/dL.

• Antihypertensives. These drugs may be needed for clients with hypertension. Because beta blockers and calcium channel blockers are used to manage hypertension as well as angina, one of these drugs may be effective for both disorders.

Dissociation constants

Procaine penicillin Procaine penicillin is a combination of benzylpenicillin with the local anaesthetic agent procaine. This combination is aimed at reducing the pain and discomfort associated with a large intramuscular injection of penicillin.

Indications

respiratory tract infections where compliance with oral treatment is unlikely ,syphilis, cellulitis