[Back to Basics] Screening Prescriptions

Madeehah R.
10 min readAug 18, 2021


NOTE: this post is intended for qualified healthcare professionals, specifically pharmacists. For any advice on specific patient medications, please contact the appropriate healthcare professional.

The [Back to Basics] series:

When I was a new pharmacist, screening prescriptions easily flustered me. I trained in community and my first job as a qualified pharmacist was in hospital, so I was already trying to adjust to a new environment, larger team, and different expectations.

My formal training in clinically screening prescriptions was a little patchy. I knew the information in the BNF like the back of my hand in preparation for the pre-reg exam, but how does that translate into practical skills when you’re trying to screen hundreds of scripts or drug charts throughout the day on top of the other daily tasks?

This isn’t a definitive guide on clinical screening because, really, there’s far too much information for that. But this guide will hopefully show newly qualified pharmacists a more practical, common-sense method of approaching prescriptions.

What is ‘screening’?

Screening, or clinically checking a prescription, is a core skill for pharmacists. You must ensure that each medicine is both safe and effective for the patient and the indication they present with.

Essentially, you’re making sure that the right medicine goes to the right patient at the right time.

But the ‘right medicine’ can mean several different things!

Clinical screening involves checking the following:

  • Dose of regimen (is this for a paediatric patient? Any renal/hepatic impairment?)
  • Strength (is this licensed?)
  • Indication (is this a licensed medication for a particular condition/does it have a well-documented practice?)
  • Drug-drug Interactions
  • Drug-Other interactions (e.g. food, patient factors)
  • Formulation (can the patient swallow or open bottles of medication?)
  • Allergy status

This isn’t even the complete list! As you can see, there’s a lot to check. Screening can be overwhelming and confusing, especially if you don’t have a process in place.

With experience, a lot of these checks become second nature, but before you’ve reached that stage it’s handy to have a few common-sense steps to aid you.

TOP TIP: Take each item independently, then cross-check it with each other.

Four MAIN checks on each prescription item:

1. Does the prescription make sense for this patient?

It sounds obvious, but you’ll be surprised how much common sense can make all the difference!

There will always be exceptions to the rule, but most prescriptions fit to a patient story, even before we get to the nitty-gritty dose instructions.

Think about your PATIENT, not just the prescription.

When you see:


Aspirin 75mg OD

Amlodipine 10mg OD

Irbesartan 150mg OD

Metformin 500mg BD

You might get the idea that this is a man in his 60s with diabetes and likely to have some kind of cardiovascular history. He’s on two anti-hypertensives, so that’s to keep in mind in case there are any other meds that might lower his blood pressure (there aren’t any here).

But what if you see:


Metformin 500mg TDS

Type 1 Diabetes can occur in young people, but metformin is only used for type 2. So why is this young woman in her early twenties taking metformin?

This is where you mentally query the prescription because it is unusual (not too unusual, however).

The patient could be pregnant, in which case she might have gestational diabetes, or she could be taking it to treat polycystic ovaries syndrome.

Can you see how the prescription tells a story, not just with the medication but also with the patient factors?

Understand not just the drugs and doses, but the person in front of you.

2. Does this dose instruction make sense as it stands?

Amlodipine 10mg once a day sounds about right.

Quinine sulfate 200mg once at night? Good to go.

But what about…

Simvastatin 40mg, take one in the morning?

Or morphine sulfate 10mg, take as directed?

Doxycycline 100mg, take one daily (no duration specified)?

How would you tackle each of these prescriptions? Think about the context the prescription is in.

If you’re in a hospital, did the script come from a specific outpatient clinic that often uses unlicensed doses or indications? Even then, you can still challenge a prescription if you’re not happy with it.

If you have access, ask the patient or check their clinical notes for clues. Sometimes being a pharmacist means being a detective: an odd prescription is a mystery, so you need to piece together WHY that prescription came about as it did.

There could be a very good reason for this, or it could be bad prescribing practice.

Here’s what you could do for each of those examples:

Simvastatin → contact the prescriber and let them know that it’s best taken at night due to its mechanism of action

Morphine → CD prescriptions should have specific dose instructions. Contact the prescriber to ask them to amend the prescription

Doxycycline → did the patient notes specify a duration/does the patient know how long to take it for? Is it for a longer duration indication, like acne, or a prophylactic indication? If you’re unsure from your available resources, you can ask the prescriber just to double-check.

TOP TIP: The clinical nuances of each drug will come with experience (e.g. making sure epilepsy meds are given by brand)

3. Are there any monitoring requirements to keep in mind?

You may not always have access to blood tests and observation charts, but this step is important to think about.

Even when I’m checking scripts in community, in the back of my mind I’ll make the mental connection between the drug and the specific monitoring requirement that I might have followed up on had I been in a different setting.

But monitoring requirements doesn’t just mean tests and numbers, it also means signs and symptoms the patient might want to watch out for.

When clinically checking your prescription, think: is this the first time the patient is having this? Are they aware of any side effects?

Let’s go back to one of our examples and break them down by how you might handle the prescription depending on the setting you’re in.

Simvastatin 40mgOne To Be Taken At Night


Dose and frequency look good, but I’ve checked the PMR system and it’s the first time we’re dispensing for this patient. I ask them if it’s their first time having this medicine. They confirm that it is and that they’re not on any other medication.

Once dispensed, I’ll counsel the patient by explaining it’s a relatively high dose to be started on (they say the GP did mention this, but their cholesterol was ‘through the roof’). I note this down and let them know that there is a potential side effect of muscle cramps, which might be exacerbated by the high dose. The patient is happy to try but I let him know to contact us or his GP in the next two weeks if there is any change to his side effects.


The dose, frequency and strength look fine. The medication comes from the patient’s history, and he states that he takes it every day.

I have a look at his total cholesterol and LDL levels which are slightly raised, but his liver function tests are within range. There’s nothing in his notes to link his clinical condition to raised cholesterol, so I make a note to flag this to his GP on discharge.

Primary care:

Primary care is slightly different. I might come across this prescription when reviewing a patient’s long term medication, or doing hypertension/vascular health clinics.

I can have a conversation with the patient about their adherence and if they’re happy taking the statin, and then review their total cholesterol, LDL, and liver function.

For this patient, he hasn’t had his bloods checked since last year! His cholesterol and LDL were slightly higher last year, and he’s been taking the statin for a few years now.

I let the patient know this, and we discuss some healthy living advice. I then print off a blood test form and let him know to get it done within the next couple of weeks, and that we’ll be touch regarding its results.

TOP TIP: if I have access to blood tests (e.g. in hospital/GP), I like to check them first before even considering the prescriptions.

That way, I’ll know if there are any special considerations to keep in mind when reviewing scripts e.g. renal/hepatic impairment, abnormal electrolytes, low/high blood pressure.

I can then use these as a route of query should anything arise from their prescriptions.

4. Can the patient practically take this medication?

Most patients are able to swallow tablets, but there are certain circumstances where you have to take other considerations if patients cannot swallow tablets.

This goes back to step 1, telling the story of the patient.

Do they have an NG/NJ tube?

Do they struggle to open blister packs or open bottle lids of medications?

Do they understand how to measure out 5 mL of a liquid antibiotic?

Understand the whole picture of a patient and you’ll find yourself considering clinical checks in a far more holistic and patient-centred way.

Two FURTHER checks on the prescription as a whole:

5. Any drug vs drug interactions OR patient vs drug interactions?

This step is usually easier if you had a prescription with two or three medications.

But what if you have a drug chart with fifteen different drugs, all for a complex patient?

With experience you learn to pick out the medications that would concern you the most, but here’s an easier way to mentally process interactions:

Any CYP inhibitors/inducers?

Any drugs in the same clinical category? E.g. three drugs that affect neurological state might signal you to look up their interactions

Is there more than one drug of the same class? E.g. amlodipine and felodipine

Is there more than one drug that produces the same effect? E.g. several antihypertensives

Some of these checks might not be things you want to flag to the prescriber (remember, you don’t want to inundate them with EVERYTHING you’re thinking about!), but it’ll be things for you to keep in mind and maybe monitor if you have the chance.

For example, if an elderly patient is on several antihypertensives, this could indicate a falls risk. What’s their blood pressure been like recently? If you’re in the community, perhaps talk to the patient and ask if they’ve had any falls or been feeling dizzy recently.

6. Are there any changes to the prescription if it’s a long term medication?

How will you know if something is a long term medication?

Again, think about the story of the patient. For example, if this is a newly diagnosed diabetic patient, then you can anticipate a dose change in any oral medication.

Use the patient’s PMR or drug history to investigate any changes(remember, be a detective!). If it’s a recent change you won’t have to go back too far.

Confirm with the patient (or in the patient’s notes) that this was an intentional change, and ensure the patient/you are aware of any monitoring requirements as mentioned in step 3.

What if I find an error/need to query something?

First of all, don’t be nervous! Remember, your job is to ensure the safety of medications. You are essentially the gatekeeper of medications, so you’re well within your right to query anything you deem query-able (that’s a word…).

Here are a few practical steps:

  • Contact the prescriber, whether in GP or within the hospital (you might have to leave a message)
  • If the patient is waiting, you can ask them in case they might know, but if you are querying something with the prescriber ensure you explain this to the patient so they’re aware of the delay
  • Explain to the prescriber the exact part of the script you are querying (e.g. dose too high for a certain indication) and suggest to them the alternative

TOP TIP: Always give your own evidence-based suggestions as some prescribers will defer to your judgement. Be prepared!

Where can I check for more info?

Clinical screening doesn’t need to be difficult. The best way to develop a good screening practice is to take your time initially and not let anyone rush you (easier said than done, perhaps).

Your job is the safety and efficacy of medications, and you can’t do that with a distracted mind.

Take these steps with a mind of flexibility, and remember to keep the bigger picture of the patient in mind.

If you found this guide useful, buy me a coffee!

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Clinical Check Guidance — Pharmacy Forum NI

Clinical Check — RPS Quick Reference Guide

Originally published at https://madeehahreza.com on August 18, 2021.