Types of different inhalers

I did some refreshing on the types of inhalers as well as common problems and advantages of each type of inhaler 

Metered Dose Inhaler

·         First introduced in 1956

·         Developed with a small particle size (<5 microns) and able to get to lower airways with minimal systemic effects

o    Lung distribution of 50-60% in new HFA formulation

·         Medication is contained in a liquefied compressed gas that maintains a certain pressure.

·         Used to use CDC propellants, now use HFA propellants

o    New HFA propellant is more polar which has limited solubility with a lot of compounds

·         Only two drugs with MDI HFA formulations: albuterol and beclomethasone dipropionate

·         Two types of MDI

o    Breath-actuated inhalers- automatically release a spray of medication with an inhalation (pirbuterol)

o    Press and breathe inhalers- requires push of button to release medication (albuterol)

·         Common errors in the press and breathe MDI

o    Forget to remove the cap or shake the inhaler

o    Use the inhaler upside down

o    Press down before inhalation

o    Press down after inhalation complete

o    Don’t hold breath after inhalation

Dry Powder Inhaler

·         Does not contain a propellant, all are currently breath-actuated

·         Requires force of inhalation to get medication into the lungs

o    Problematic especially during asthma attacks or with young children

·         Must inhale all medication in one or two breathes and can be difficult to judge

·         Over 17 varieties

o    Single-dose models- load capsule into the reservoir and inhale the dose

o    Multi-dose model- have a reservoir of powder which needs to held upright before loading a dose for inhalation

·         Common errors of inhalers

o    Failure to remove cover

o    Incorrect dose loading

o    Failure to pierce capsule

o    Breathing out of device

o    Blocking inhalation vents

o    Poor seal around the mouthpiece

o    Not inhaling with enough speed or velocity

o    Inhaling through the nose

Respimat Soft Mist Inhaler

·         Use liquid formulation like a nebulizer but in a multi-dose device

·         Inhaler is powered via compressed spring and there is no propellant in the inhaler

·         Lower spray velocity and long duration versus MDI

o    Higher lung deposition

o    Lower doses without decreasing efficacy

·         Contains higher fraction of fine particle than most MDIs or DPIs

·         Common errors

o    Failure to prime or load dose

o    No exhalation

o    Inhalation issues: firing device before inhalation, firing device after inhalation, discontinuing inhalation early, inhaling too quickly

o    Don’t hold breath

o    Block vents with mouthpiece

Nebulizer

·         Electric or battery powered machine that turns liquid medication into a mist

·         Allows for various medications to be administered: anticholinergics, antibiotics, and mucolytics are some examples

·         Don’t require coordination of breaths and release of medication

·         Disadvantages:

o    Large devices

o    Treatments take a long time (can be about 15 minutes)

o    Requires extensive cleaning to prevent an infection

o    Requires a power source

o    Typically not portable

Atrial Fibrilation

The past week I have done a review on A. Fib and reviewed treatment and when to use oral anti-coagulation and when to avoid it.

»          Background

o    Irregular heartbeat that is caused by rapid, disorganized electrical signals

§  These signals cause the atria to contract very fast and irregularly (fibrillate)

o    Currently 33.5 million people worldwide have AFib

§  3 million Americans (expected to rise to 8 million)

o    70% of those with AFib are between the ages of 65 and 85 years old

o    Caucasians are more likely to develop AFib than other ethnicities

o    Risk factors for development are: hypertension, coronary heart disease, heart defects, heart failure, rheumatic heart disease, pericarditis, hyperthyroidism, obesity, diabetes, lung/kidney disease, sleep apnea, and a family history

o    Other behavioral factors include: caffeine abuse, alcohol abuse, and stress

»          Pathophysiology

o   In a normal heart the SA node (right atrium) begins the electrical signaling. It sends signals to begin a new heartbeat 60-100 times a minute. From the SA node, the electrical signal moves to the right and left atria. This causes a contraction and blood is pumped to the ventricles. Once in the ventricles, the electrical signal moves to the AV node which slows the signal down so the ventricles can fill with blood. Once leaving the AV node the ventricles contract and blood is pumped to the rest of the body.

o   In AFib, electrical signals begin in a different part of the atria or pulmonary veins, not the SA node. Those electrical signals all stimulate the atria causing the fibrillation and they flood the AV node causing the ventricles to beat faster (just not as fast as atria). This causes the atria and ventricles to not beat in a coordinated way causing a fast and irregular heart rhythm. The blood is not pumped out of the ventricles in a regular fashion so the body gets inconsistent amounts of blood

o   There are 3 common types of AFib

§  Paroxysmal or temporary: faulty electrical signals begin suddenly but stop on their own Usually stop within 24 hours

§  Persistent: Abnormal heart rhythm lasts for more than a week and either stops on own or with treatment

§  Permanent: Normal heart rhythm cannot revert to normal with treatment

»          Symptoms/Diagnosis/Complications

o   Not everyone has symptoms of AFib

o   Commonly patients present with general weakness and fatigue

o   Other symptoms include:

§  Rapid, irregular heartbeat

§  Fluttering or thumping in the chest

§  Shortness of breath and anxiety

§  Chest pain or pressure  

o   Diagnostic tests include: EKG or Holter monitor which can show images of the heart

o   Two major complications of AFib: stroke and heart failure

§  Stroke: Some blood is not pumped out of the atria causing pooling and a clot is formed which can travel to the brain

§  Heart Failure: Heart does not pump enough blood to meet the needs of the body. In AFib the ventricles are beating quickly to keep up with the atria and are unable to completely fill with blood

»          Treatment

o   Multiple goals of therapy which use different medications

o   Goal 1: Prevent blood clots from forming

§  Risk assessed via CHADS2-VASc score (heart failure, hypertension, age, diabetes, previous stroke, women, PVD, and age >65)

§  One of the most common treatments of AFib

§  Most common medications are warfarin and aspirin

·         Aspirin is preferred with lower stroke risk (score of 0 or 1)

·         >2 is high risk and oral anticoagulation should be considered

§  Other medications include: dabigatrin, rivaroxiban, apixaban, and endoxaban

·         Recently approved in non-valvular AFib

·         Advantages: no routine monitoring required, not affected by diet or supplements, and less likely to cause hemorrhagic stroke versus warfarin

·         Disadvantages: effects disappear shortly after a skipped dose and no antidote if bleeding occurs

o   Goal 2: Rate control

§  Slow down the rate of ventricle beats therefore decreasing the heart rate

§  Recommended treatment for those with AFib

§  Medications that control rate include:

·         Beta blockers

o   Cardio selective: metoprolol, atenolol, bisoprolol

o   Non-cardio selective: carvedilol, propranolol, nadolol

·         Calcium channel blockers

o   Slow heart rate and decrease strength of contraction

o   Diltiazem and verapamil

·         Digoxin- slows conduction of electrical currents

o   Goal range: 1-2ng/mL

o   Goal 3: Rhythm control

§  Attempt to restore abnormal rhythm back to normal

§  Medications that control rhythm include:

·         Sodium channel blockers- slow ability to conduct electricity

o   Flecanide, propafenone, and quinidine

·         Potassium channel blockers- slow down electrical signals that cause AFib

o   Amiodarone, sotalol, and dofetilide

§  Surgical intervention

·         Electrical cardioversion- use electrical shocks to convert to normal rhythm

·         Catheter ablation- restores normal rhythm through radio waves

»          Prevention

o   Lifestyle changes

§  Healthy diet

§  Low sodium diet

§  Smoking cessation

§  Stress reduction

o   Monitor other chronic conditions

§  Hyperlipidemia, hypertension, and hyperthyroidism

Bydureon

Today I just did research related to the Bydureon injection. It GLP-1 agonist that is injected once weekly to augment treatment of diabetes. It is the longer acting version of Byetta which also contains exenitide as the active ingredient. Bydureon contains the medication in small microspheres which controls the release the medication all week. Like all other insulin pens it should be injected in the thigh, abdomen, or back of the arm. Overall studies have shown that Bydureon that with diet and exercise or other diabetes medications this injection can lower the A1C by 1.6% on average and weight by almost 5 pounds. If a person misses a dose and is within 1 or 2 days of the next dose they should wait until their next dose. If it is >3 days away they can go ahead and inject the dose. Each time before injecting the dose the pen should be left at room temperature for 15 minutes to allow the powder to warm up. The pen needs to mixed back and forth numerous times before injecting. It should appear as an uniform, cloudy mixture. This medication is not a first line treatment for diabetes but can provide great augmentation if needed.

Idarucizumab

7/6/15
Today I read a study about dabigatran reversal with idarucizumab which is an antibody fragment to reverse the effects of dabigatran. Although this study is still in progress, it looked at the first 90 patients who were enrolled in the study. It grouped people into two groups: 1) had serious bleeding and 2) required an urgent procedure. Overall, in these patients the test results (dilute thrombin time and clotting test) were reversed in 88-98% of patients in minutes. In all the patients who received the reversal medication, only one patient had a thrombotic event before restarting anti-thrombotic therapy.

EpiPen Administration

7/1/15

Today I review counseling instructions on EpiPens. I wanted to make sure I was confident in counseling them so patients could accurately administer them in an emergency. First, each box of EpiPens comes with a training pen which should be used by the patient to practice so they are prepared if they need to use it.

When using the EpiPen:
1. First remove the pen from the carrying case
2. Remove the blue safety pin to activate the pen
3. Using a swinging motion inject the pen into the upper thigh (it must not be inject anywhere other than the upper thigh)


As soon as an EpiPen is used 911 needs to be called immediately since it is an emergency. It is important to hang on to the used pen so they can see that the pen has been used. If it has been 15 minutes and another dose is needed another EpiPen can be used if emergency personnel have not arrived.

There is a program Mylan provides for schools that allows qulifying public and private schools in the US who have a valid prescription get 4 free EpiPen Jr or EpiPen. If they use that supply prior to the annual eligibility date they can receive 4 new ones at no additional cost. This is a great program because it provides school children access to EpiPens in case they do not have one or do not know that they have an analphylaxis response to a medication.

Plan B Education

6/30/15

Today I did research education about the rule change for Plan B. In 2013, the FDA made the ruling that the Teva brand Plan B products were now approved for those 15 years and older (encompassing those women of child bearing potential). They decided that there should be no restrictions related to age or point of sale. This education was provided to the pharmacists and a note was placed by the product on the shelf.

Hyperlipidemia Treatment in Childhood

6/29/15

On Monday, I was given the chance to talk to a patient who was new to treatment for her hyperlipidemia. She had a lot of questions about her new statin and mentioned all of her children had used Zetia while they were children. She was wondering why she was prescribed a statin rather than Zetia like her children had. I had never encountered a child who has used therapy for hyperlipidemia so I wanted to look up the guidelines for the pediatric population.

I looked at the American Academy of Pediatrics for reference on the issue. As for nutrient recommendations no diet restriction is recommended for those <2 years of age because that is when growth and development require the highest energy intakes. They recommend that by 5 years of age their diet should contain <20% from fat.

Screening recommendations for children are as follows:
1. Screen children and adolescents whose parents or grandparents at <55 years of age underwent an arteriography and were found to have diagnostic coronary arteriography.
2. Screen children and adolescents whoe parents or grandparents at <55 year of age had a documented MI, angina, PVD, CVD, or sudden cardiac death
3. Screen if parent has cholesterol level >240mg/dL
4. Screen if parental history is unobtainable especially with other risk factors

If the initial level is >200 a fasting test should be done to obtain HDL/LDL. If the total cholesterol is 170-199 a second measurement should be obtained and averaged with the first measurement.

Drug Therapy
Only consider for children >10 years after an adequate diet trial for 6-12 months whose LDL is >190 or whose LDL is >160 and there is a family history of cardiovascular disease or 2 or more risk factors are present in the child.
Recommended first line therapy is: bile acid sequentrants