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Pneumonia Pharmacology

Updated: May 26, 2022

Pneumonia is an acute respiratory infection of the lung parenchyma caused by one or co-infecting pathogens. These pathogens cause the lung parenchyma (alveoli) to become inflamed and fill with pus and fluid, limiting oxygen intake and making gas exchange ineffective.

In these notes, we’ll be going over the Pneumonia Pharmacology as well as the medical tests required to determine the severity. But before getting into that, make sure that you’ve understood the:


Introduction to Pneumonia Pharmacology

When treating Pneumonia, the main goal is to support the respiratory system and improve gas exchange. The most efficient way to do this would be to directly target the infecting pathogen, but it’s not always possible. As we mentioned in previous notes, Pneumonia can be caused by several different pathogens, all of which can be viral or bacterial. If the patient tests positive for a bacterial pathogen, then antibiotics will be prescribed to stop the infection.

However, if the pathogen is a virus, antibiotics won’t work and no medication would stop the infection. The patient’s body would have to fight it off naturally, and all we can do is treat the symptoms. In addition, there are several cases where the infecting pathogen is not discovered because the sputum samples or blood cultures would not be conclusive. So again the pharmacological treatment would be supportive.

Pneumonia Pharmacology: Antibiotics

When a patient is diagnosed with bacterial Pneumonia they are typically started on broad-spectrum IV Antibiotics to suppress the infection as early as possible. The choice of antibiotics depends largely on the patient’s condition and whether they have any known Multi-Drug Resistance (MDR).

Patients who have no known MDR are typically prescribed monotherapy, meaning only one antibiotic. With the most common choices being:

  1. Ceftriaxone

  2. Ampicillin

  3. Levofloxacin

  4. Ertapenem

On the other hand, patients with a known MDR are treated much more aggressively, and they will often be prescribed a three-drug combination therapy. Typically, the patients would get two Anti-Pseudomonal Antibiotics such as:

  1. Cephalosporin

  2. Ceftazidime

  3. Carbapenem

  4. Tazobactam

  5. Fluoroquinolone

  6. Aminoglycoside

And another antibiotic including:

  1. Linezolid or

  2. Vancomycin

Table 1 Give an Overview of Antibiotics used in Pneumonia

*This information does not contain all possible side effects and drug interactions, it is for educational purposes only.*


Generic Examples

Side Effects

Drug Interactions

Cephalosporins 1st Generation







Cephalosporins 3rd Generation














Valproic Acid


Tazobactam - Piperacillin

















​Chelation Agents


Antidiabetic Agents




​Stomach upset


Kidney damage


No known severe drug interactions



Oral thrush

Abnormal liver function tests







​Bitter taste

Flushing of face

Low blood pressure


Live vaccines

Pneumonia Pharmacology: Oxygen Therapy

Pneumonia affects the individual’s respirations which often results in limited oxygen uptake and hence a decrease in oxygen saturation within the body. Oxygen therapy aims to keep the patient’s arterial oxygen saturation (SpO2) above 92% and their partial pressure of oxygen in the blood over 60 mmHg. However, lower values might be accepted if the patient has any chronic respiratory illnesses such as COPD as they would be at risk of developing carbon dioxide retention.

The mode of administration for oxygen therapy depends on the patient’s physiological condition and the amount of oxygen they need to keep their SpO2 within a normal range:

  1. Nasal cannula delivers up to 5L/min

  2. Normal face mask delivers up to 15L/min

  3. A non-Rebreather mask can be used to administer a high-flow system

Moreover, if hypercapnia occurs, the patient might need Non-invasive positive pressure ventilation (NPPV) which pushes oxygen into the patient’s lungs and forces carbon dioxide out of the lungs.

Pneumonia Pharmacology: Mucolytics

When a respiratory infection occurs, the airways become irritated and start to produce excessive amounts of mucus to act as a physical barrier against irritants. However, apart from blocking the irritants, the mucus will also limit oxygen intake and obstruct airflow. The only way to clear out the excess sputum is to cough it up but in some cases, this might be challenging. Either because the mucus would be very thick or because the patient would be frail and wouldn’t have enough energy to cough effectively.

In either of these cases, Mucolytics are prescribed to decrease the viscosity of the mucus and make it easier to expectorate it (cough it up).

The most commonly used Mucolytics are:

  1. Ambroxol

  2. Bromhexine

  3. Carbocysteine

  4. Erdosteine

  5. N Acetyl Cysteine

  6. Sobrerol

Pneumonia Pharmacology: Expectorants

Similar to mucolytics, the aim behind the use of expectorants is to help the patient clear their airways from the build-up of mucus. With most of the expectorants being derived from plants, their use is sometimes overlooked. However recent studies have shown that botanical expectorants reduce the viscosity of mucus and assist patients to cough up secretions more easily. Moreover, some of these medications also have antibacterial, antiviral and antitussive properties, giving them an overall advantage to their use in respiratory illnesses.

The most commonly used expectorants are:

  1. Guaifenesin

  2. Glycyrrhiza glabra

  3. Pelargonium sidoides

  4. Hedera helix

Pneumonia Pharmacology: Antipyretics

Like any other infection, pneumonia will likely cause a spike in fever so antipyretic medication is prescribed to suppress the high temperature. While NSAIDs such as ibuprofen or aspirin are great at treating fever, they are contraindicated in respiratory illnesses as they might worsen the patient’s condition. Several studies show that NSAIDs negatively affect the local airway immunity and they’ve also been linked to higher complications during active pneumonia.

With this in mind, Paracetamol becomes the first choice of antipyretic when treating pneumonia. In addition, Paracetamol also acts as an analgesic which becomes useful if the patient is experiencing a headache or muscle pains during the infection.

Those are the most commonly used drugs when caring for patients with pneumonia. 

If you’ve got any questions you can send a message on my Instagram @Miriana.Nurse

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  1. Gupta R, Wadhwa R. Mucolytic Medications. [Updated 2022 Jan 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:

  2. Scaglione, F., & Petrini, O. (2019). Mucoactive Agents in the Therapy of Upper Respiratory Airways Infections: Fair to Describe Them Just as Mucoactive?. Clinical medicine insights. Ear, nose and throat12, 1179550618821930.

  3. Albrecht, H. H., Dicpinigaitis, P. V., & Guenin, E. P. (2017). Role of guaifenesin in the management of chronic bronchitis and upper respiratory tract infections. Multidisciplinary respiratory medicine12, 31.

  4. Marvisi, M., Balzarini, L., Mancini, C., & Ramponi, S. (2019). Pneumonia. Ventilatory Support and Oxygen Therapy in Elder, Palliative and End-of-Life Care Patients , 89–95.

  5. Voiriot, G., Philippot, Q., Elabbadi, A., Elbim, C., Chalumeau, M., & Fartoukh, M. (2019). Risks Related to the Use of Non-Steroidal Anti-Inflammatory Drugs in Community-Acquired Pneumonia in Adult and Pediatric Patients. Journal of clinical medicine8(6), 786.

  6. Damien Basille ,Reimar Wernich Thomsen, Morten Madsen, Pierre Duhaut, Claire Andrejak, Vincent Jounieaux, and Henrik Toft Sørensen. Nonsteroidal Antiinflammatory Drug Use and Clinical Outcomes of Community-acquired Pneumonia

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