Ramelteon (Rozerem) Pharmacology Podcast

On this episode, I discuss the pharmacology, adverse effects, and drug interactions of ramelteon (Rozerem).

Ramelteon is primarily only helpful for sleep onset and generally is not that helpful in sleep maintenance.

CNS depressant drug interactions will be a common concern to monitor. Opioids, benzodiazepines, and alcohol are common sedatives that can add to the effects of ramelteon.

Some of the CYP enzymes break down Ramelteon. I discuss this in greater length in this podcast episode.

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Phentermine Pharmacology Podcast

In this podcast episode, I break down the pharmacology, adverse effects, pharmacokinetics, and drug interactions of phentermine.

Phentermine has some CNS stimulant activity so adverse effects like insomnia, hypertension, and tachycardia are possible.

Pay attention to drugs that can oppose the effects of phentermine and cause weight gain such as mirtazapine and sulfonylureas.

Phentermine is a controlled substance so the risk of addiction and dependence is possible.

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Zaleplon Pharmacology

On this episode, I discuss the pharmacology of zaleplon including side effects, drug interactions, and important clinical pearls.

Zaleplon is a non-benzodiazepine sleep aide commonly known as Sonata. It is commonly used for sedation and the management of insomnia. Zaleplon is a controlled medication, with a high risk for dependence, and because of that, it is best used to treat short-term insomnia. The pharmacology of zaleplon is similar to other sleep aids like Ambien, and Lunesta; they all have an impact on GABA. Specifically, zaleplon regulates the GABABZ receptor. The GABABZ receptor has been shown to be responsible for the pharmacological properties of benzodiazepines which produce sedative, anxiolytic, relaxant, and anticonvulsive effects. For pharmacokinetics, zaleplon has a general onset of action around 30-60 minutes, because of that it is best dosed closer to bedtime. 

For sedatives, and other drugs similar to zaleplon, it is generally better to start at lower doses in geriatrics and smaller patients. The commonly accepted dosing is between 5-20 mg, but it is best to use non-pharmacological therapies, instead of pharmacological whenever possible. The most common side effect that may be experienced with zaleplon is next-day sedation, also known as hangover sedation. Loss of mental clarity, dizziness, and confusion may also be present. Serious side effects of taking zaleplon are abnormal sleep behaviors, which it carries a US boxed warning for, and risk of dependence. Zaleplon is also on Beer’s list because of the increased risk of falls, delirium, and increased complications while driving due to sedation and lethargy. 

When a sedative is first prescribed, it’s important to first look at the other medications a patient may be taking to see if that’s what may be causing insomnia. For example, a diuretic administered at night can cause excessive urination that can lead to insomnia. The addition of stimulants too late in the day can also cause that, and similarly, lifestyle changes like increased intake of caffeine can increase the risk for insomnia as well. 

Most of the drug-drug interactions that zaleplon has are due to additive depressive effects. Examples include alcohol, opioids, older antihistamines, trazodone, or any medication that can cause sedation. There is also a smaller risk for CYP3A4 interaction. Concurrent administration of an inducer, like St. John’s Wort, or carbamazepine, can lower the concentrations of zaleplon. Likewise, inhibitors may increase concentrations.

In cases of overdose, the signs and symptoms that will most likely precipitate are exaggerations of zaleplon’s adverse effects. The manifestations of CNS depression can range from drowsiness to coma. More mild cases might have drowsiness, confusion, and lethargy; while more serious cases may have ataxia, hypotonia, hypotension, respiratory depression, coma, and death. To treat a zaleplon overdose, symptomatic and supportive measures are necessary along with gastric lavage. Animal studies suggest that flumazenil is an antidote as an antagonist to zaleplon, but there is no human data. With proper treatment, recoveries have been made with overdoses greater than 200 mg. In instances where the outcome was fatal, it was most often associated with the use of additional CNS depressants.

Show notes provided by Chong Yol G Kim, PharmD Student.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

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Flippin’ Pharmacology Flash Cards

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Meded101 Guide to Nursing Pharmacology (Amazon Highly Rated)

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Resources

Paragraph 1: taken from podcast, also taken from https://go.drugbank.com/drugs/DB00962#pharmacodynamics

Paragraph 2: taken from podcast

Paragraph 3: taken from podcast

Paragraph 4: taken from podcast

Paragraph 5: taken from FDA label

Doxylamine Pharmacology

In the podcast this week, I talk about doxylamine pharmacology. Doxylamine is a first-generation antihistamine; it is commonly an active ingredient in night-time medications like Unisom, Nyquil, and Mucinex. The pharmacology of doxylamine is similar to other first-generation antihistamines, it competitively inhibits the binding of histamine at H1 receptors. Its main uses are as sleep aides, in cough-and-cold medications, but doxylamine has also been given with pyridoxine to treat nausea and vomiting during pregnancy.

Doxylamine’s adverse reactions are related to its anticholinergic properties, they include dry eyes, dry mouth, increased fall risk, sedation, urinary retention, constipation, and confusion. Contraindications include concurrent use with a monoamine oxidase inhibitor, known hypersensitivities, concomitant alcohol use, and if the patient has the following conditions: elevated intraocular pressure, narrow-angle glaucoma, asthma, peptic ulcer disease, urinary bladder neck obstruction, or gastric outlet obstruction. It is also a Beer’s list drug due to its anticholinergic effects. The normal dose in adults is 25 mg. In cases of overdosage, the most common manifestation is exacerbations of its anticholinergic effects. The major complications of an overdose include arrhythmia, respiratory failure, seizures, hyperthermia, rhabdomyolysis, and coma. 

When you know a patient is taking doxylamine, it’s important to be cognizant of their occupation, as well as what other conditions they may have. For example, doxylamine should be used with caution in patients that drive heavy machinery due to its sedating properties. You might be able to tell if a patient’s experiencing an adverse reaction exacerbation if they begin having worsening dementia symptoms or increased urinary retention. Other indications include the use of artificial tears, or saliva, or increased complaints of constipation. To monitor for doxylamine, it’s important to monitor the patient’s tolerability. The onset of doxylamine is relatively quick as well, with a peak concentration within 2-4 hours.

For drug-drug interactions, CYP interactions aren’t as concerning as usual. The main interaction to consider when a patient is taking doxylamine is additive anticholinergic effects. Sedative effects can increase when benzodiazepines, skeletal muscle relaxants, opioids, or antihistamines are concurrently taken. Doxylamine can also counteract the usefulness of dementia or BPH medications due to its anticholinergic properties. There is also a risk of increased anticholinergic burden when taken with skeletal muscle relaxants or tricyclic antidepressants. 

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Show notes provided by Chong Yol G Kim, PharmD Student.

Support The Podcast and Check Out These Amazing Resources!

Flippin’ Pharmacology Flash Cards

Pharmacology Crossword Puzzle Book (Over 2,000 Clues/Questions!)

NAPLEX Study Materials

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BCACP Study Materials

BCGP Study Materials

BCMTMS Study Materials

Meded101 Guide to Nursing Pharmacology (Amazon Highly Rated)

Guide to Drug Food Interactions (Amazon Best Seller)

Drug Interactions In Primary Care (Amazing Resource for Practicing Clinicians)

Perils of Polypharmacy (Great Resource for Those Who Work in Geriatrics)

Zolpidem Pharmacology

Zolpidem enhances the action of GABA which is an inhibitor neurotransmitter.

Zolpidem metabolism can be impacted by the use of CYP3A4 inhibitors. Concentrations can rise on account of this potential interaction.

It is important to remember to go slowly when tapering off zolpidem. Particularly in patients who have been on the drug for a long time or those who are on higher doses.

Abnormal sleeping behaviors like sleep-walking, eating, or driving have been reported with zolpidem.

Remember that CNS depressant drug interactions can happen with zolpidem. Take note of any other sedating medications prior to starting zolpidem.

I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Doxepin Pharmacology

Doxepin is under the class of tricyclic antidepressants. It can inhibit the reuptake of serotonin and norepinephrine.

In addition to the serotonin and norepinephrine reuptake inhibition mechanism, doxepin also has antihistamine type effects.

Because of the anticholinergic activity of doxepin, it is recommended to avoid this medication in the elderly, particularly at high doses.

Be aware that anticholinergics like doxepin can reduce the benefit of dementia medications.

CYP2D6 is an important enzyme in the metabolism of doxepin and drugs like bupropion that inhibit CYP2D6 can increase the concentrations of doxepin.

I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Trazodone Pharmacology

Trazodone pharmacology is complex. It can inhibit serotonin reuptake, block histamine receptors, and possibly have alpha-blocking activity.

Side effects of trazodone include sedation, dizziness, and dry mouth. Rarely, priapism may occur. I’ve seen this nugget come up on pharmacology exams!

While trazodone is classified as antidepressant, it is often used to help manage insomnia.

Trazodone can possibly prolong the QT interval. Risk of other medications and patient specific parameters should be considered.

Trazodone concentrations can be increased with the use of CYP3A4 inhibitors and reduced with 3A4 inducers.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!