Somerset CMDU Crib Sheet

To be considered for antiviral covid medication, patients must have

• Tested positive for Covid 19 (Lateral Flow Test))
• Be high risk for progression to severe covid as per NICE criteria (see below)
• Have symptom onset within the last 5 days
• Have mild to moderate symptoms of covid not requiring hospital admission

These links provide supporting information on the NICE definitions of high-risk groups:

• Risk Factors for Progression to Severe Covid in Adults.
• Risk Factors for progression to severe covid in Young people aged 12 to 17 years.

This link provides information on how patients can obtain Lateral Flow Tests & which pharmacies offer these free of charge to eligible patients.

CMDU Assessment Checklist

This checklist and supporting information below will help in your CMDU assessment.

Covid Antiviral Medications

• Paxlovid is the first line Covid antiviral medication for eligible patients. Paxlovid is a combination of 2 oral medicines called nirmatrelvir and ritonavir. Nirmatrelvir stops the virus from growing and spreading, and ritonavir helps nirmatrelvir from being broken down in the body long enough to do its job.
• From 1st Dec 2025, we will no longer be referring onwards for IV Sotrovimab. This is due to evidence showing that this no longer works against existing Covid strains. 
• BrisDoc will not be prescribing other oral covid antiviral medications such as Molnupiravir
• We will not be prescribing for patients under 18 years, although we can support referral onwards to secondary care for consideration of antivirals for eligible patients.

Before prescribing Paxlovid, consider the following:

Patient’s renal function

• Paxlovid is contraindicated in severe renal impairment (eGFR ≤30 mL/min)
• Paxlovid requires a dose adjustment in moderate renal impairment (eGFR 30-60mL/min)
• Use your clinical judgement about how recently an eGFR has been taken

Patients Hepatic function

• Paxlovid is contraindicated in severe hepatic impairment (Child-Pugh Class C)

Allergy/tolerance status

• If the patient has a history of clinically significant hypersensitivity reactions

(e.g. toxic epidermal necrolysis (TEN) or Stevens-Johnson syndrome) to the active ingredients or excipients, Paxlovid is contraindicated

• If the patient is intolerant to lactose or galactose – nirmatrelvir contains a lot of lactose
• If the patient has a lactase deficiency or glucose-galactose malabsorption

Pregnancy, Breastfeeding and Contraception

• Is the patient pregnant? Paxlovid is not recommended during pregnancy
• Is the patient breastfeeding? Breastfeeding is not recommended during treatment with Paxlovid and for 7 days after the last dose of Paxlovid
• Check if the patient is taking hormonal contraception containing ethinyl estradiol.

If so, provide advice on using an additional non-hormonal contraception during the five days of Paxlovid treatment and until one full menstrual cycle after stopping Paxlovid

Drug Interactions

Obtain a comprehensive list of the patient’s medication including over the counter and herbal supplements, alongside their digital medication records.

Check the patient’s other medications for interactions, the need for dose adjustments or increased monitoring due to drug interactions. These resources can be used:

• Liverpool COVID-19 Drug Interaction Checker
• Paxlovid Summary of Product Characteristics
• BNF Interactions checker

Further prescribing resources include:

• University of Liverpool prescribing resources, including, this Patient Assessment Resource with a flow chart of things to consider when considering Paxlovid
• This link provides a brief overview of drug-drug interactions between Paxlovid and selected drugs that may be used in the community

Is the patient taking any medication highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening reactions? If yes, Paxlovid is contraindicated.

Patient factors

• Check the patient can swallow tablets. Paxlovid tablets are large and need to be swallowed whole. They cannot be chewed, crushed or broken. Patients with swallowing difficulties may find these hard to take.             1
• Check that the patient or an appropriate representative understands and can implement any dosage adjustments required for their usual medication or for Paxlovid.
• If there is concern question over the patient’s ability to manage the treatment with Paxlovid, eg changes needed for a dosset box that are not possible to arrange, it may not be suitable.
• Age: Our CMDU service will not be prescribing covid antiviral medication to patients under 18 years but may support referral on to secondary care if antiviral treatment is indicated.

Further Prescribing Support

• The Specialist Pharmacy Service is available Mon-Fri 9am-5pm for professionals in primary care to provide further advice and support about whether to prescribe Paxlovid for a patient.

Specialist Pharmacies

Non-Specialist Pharmacies

Patients nearing the 5 day treatment threshold

Please note that from 1st Dec 2025 the previous second line IV alternative to Paxlovid (Sotrivumab) has been removed from the CMDU pathway. 

This is due to evidence showing that it no longer works against existing Covid strains.

Adults

Referrals to secondary care are made to Somerset Primary Link Service by phone: 01749 836 700. The service is open 8am –8pm, Mon- Sat.

Somerset Primary Link will arrange transport for your patient if needed and will usually call the patient back within an hour to make arrangements. Please share the required treatment window with the SPL team.

Children

• Taunton Paediatric Assessment Unit (TA1 5DA) on 01823 342072.
• Yeovil Paediatric Assessment Unit ( BA21 4AT). This unit does not have a direct phone line but you can contact the Paediatric team by requesting to speak to the on call Paediatrician team via Yeovil hospital switchboard.

UKHSA Notification

Further Clinical Assessment required

• The backdoor numbers for Somerset GP Surgeries are available on the RADAR backdoor numbers page here
• To contact the Somerset OOH provider you will need to dial 111 from an WIFI call ( to circumnavigate your Bristol location), and then select option 3 for HCPs. Alternatively the shift manager has a number that may be tried instead.
• If you are concerned a patient is very unwell and requires an ambulance, phone 999 on their behalf.

Safeguarding

If you need to make a safeguarding referral for a Somerset -based CMDU patient you can find out how to do so via this Somerset Safeguarding page:  Safeguarding - NHS Somerset ICB

All patients referred into the CMDU Service should be provided with information on

• What to do if their symptoms worsen, and where to seek advice.
  • This link may be helpful to text to patients: COVID-19 symptoms and what to do - NHS
• Infection Control Measures:
  • How to avoid catching and spreading COVID-19 infection. - NHS

If prescribing Paxlovid provide the patient with advice on

How to take the medication

The standard dosage is 300 mg Nirmatrelvir (two 150 mg tablets)  with with 100 mg ritonavir (one 100 mg tablet), all taken together orally twice daily for 5 days.

Figure 1: Ilustration of Paxlovid packaging and dosage required to be taken. You need to take all 3 tablets behind the yellow foil in the morning and all 3 tablets behind the blue foil in the evening.

Paxlovid can be taken with or without food. The tablets should be swallowed whole and not chewed, broken or crushed.

What to do if they forget to take the Paxlovid:

• A missed dose can be taken as soon as possible and within 8 hours of the scheduled time, and then normal dosing should be resumed.
• If more than 8 hours has elapsed, the missed dose should not be taken and treatment should resume according to the normal dosing schedule.

What to do if they experience side effects from Paxlovid:

• Side effects include diarrhoea, nausea/vomiting, and changes in sense of taste. These are usually minor. Anaphylaxis is rare.
• The following suggestions may mask the bad taste: Chewing sugar-free gum, having a supply of sweet hard candies (sugar-free, if preferred) or mints, sucking on ice, brushing teeth frequently or using mouthwash, and drinking plenty of fluids throughout the day.

For most people, diarrhoea and vomiting due to Paxlovid clears up after treatment and tends to be mild. Patients should be advised to drink plenty of fluids and avoid foods that may upset their stomach like spicy, fried or fatty foods.

Patient information links to send via text message

Advice for all patients with Covid 19:

• Advice on Covid 19 symptoms and what to do: COVID-19 symptoms and what to do - NHS
• Infection control advice: How to avoid catching and spreading COVID-19 infection. - NHS

Patient Information on Paxlovid can be found via the following links:

• Uk Website: Patient information for Paxlovid - GOV.UK
• This link: COVID-19 antiviral treatment: Paxlovid - GOV.UK provides patient information on Paxlovid in multiple languages,  English large print, Braille, an audio version and British Sign language version.
• Easy Read Information on Covid 19 treatments : Treatments-for-COVID-19-Easy-Read.pdf

The CMDU Service Handbook can be found on RADAR here

The CMDU Clinical Handbook can be found on RADAR here

We welcome feedback, learning and questions about the service, that can be submitted via this CMDU portal link; we hope to hold another Q& A session soon for CMDU colleagues.

CMDU Assessment Checklist