Clozapine use in adults with swallowing difficulties

Using our advice

Please see Medicines suitable for adults with swallowing difficulties (SPS page)

The choice of medicine formulation should be made on an individual basis, taking account of patient factors. Follow our stepwise guide Choosing medicines formulations in swallowing difficulties (SPS page)

There are additional considerations regarding clozapine, which are covered within this article. We suggest how clozapine may be given safely in swallowing difficulties, to avoid missed or delayed doses.

Safety considerations

Clozapine is a high-risk medicine. Consider the following points when adults on clozapine develop swallowing difficulties.

Avoid missing doses

Clozapine doses should not be missed. Clozapine tablets can be crushed (‘off-label’ use) for administration if necessary while waiting for advice on alternatives.

If doses are missed, seek advice from the person’s specialist mental health team. It can be dangerous to miss clozapine doses and restart at the full dose. If more than two days’ treatment is missed, clozapine must be restarted at the original starting dose and retitrated. Monitoring requirements may also change.

Seek specialist advice

Contact the person’s specialist mental health team for advice, but do not delay giving a dose if it can be swallowed safely. The specialist can initiate changes to brand, formulation or dose for ongoing treatment. If the person is in an acute hospital, also contact the psychiatric liaison team, if available.

Clozapine-specific requirements

Clozapine has specific prescribing, monitoring, supply and administration requirements. It can only be prescribed by brand name.

There are three brands of clozapine (one with a branded generic), each with its own monitoring service. The three monitoring services are:

• UK Clozaril Patient Monitoring Service (CPMS)
• Denzapine Monitoring Service (DMS)
• Zaponex Treatment Access System (ZTAS)

Patients can only be registered with one service at any one time. Trusts are unlikely to be registered with all three services. Clozapine is not usually prescribed or supplied in primary care.

For further information see our resources:

• Clinical considerations for patients prescribed clozapine (SPS page)
• Managing the risks associated with patients prescribed clozapine (SPS page)

Choosing clozapine preparations

In an acute situation, choice of clozapine formulation is limited to that which the person is currently prescribed. In the longer term, you may be able to switch to a different formulation or brand after discussion with the person’s mental health team. Clozapine doses should not be missed while an alternative formulation is sought.

Crushing clozapine tablets and giving with fluid or soft food is generally a safe and practical option. For people who need a texture-modified diet, use the fluid consistency or food texture that is safe for them. Our article Why and how medicines are given with soft food or thickened fluid (SPS page) explains further.

In all cases, seek advice from the person’s specialist mental health team, but do not delay giving a dose if it can be swallowed safely. The specialist can initiate changes if necessary and liaise with the appropriate clozapine monitoring service(s). The mental health team may recommend clozapine blood level monitoring if tablets are crushed or the brand or formulation is changed.

Choosing medicines formulations in swallowing difficulties (SPS page) has general advice on choosing medicines formulations for adults with swallowing difficulties.

Clozaril and Clozapine Viatris

Available as tablets and orodispersible tablets.

Can only be used if the patient, prescriber and dispensing pharmacy are registered with CPMS, the Clozaril Patient Monitoring Service.

Tablets

Available as 25mg and 100mg strengths, are scored and licensed to be split in half. They can be crushed and mixed with water or soft food; this is off-label use. The tablets are uncoated but the drug is insoluble; be careful to ensure the whole dose is taken.

Orodispersible tablets

Available as 12.5mg, 25mg, 50mg, 100mg and 200mg strengths, licensed for oral administration. They should be placed on the tongue and will rapidly disintegrate in saliva to be swallowed. Orodispersible tablets may not be suitable for people unable to control their swallow. The tablets can be dispersed in water; this is ‘off-label’.

Denzapine

Available as tablets and oral suspension.

Can only be used if the patient, prescriber and dispensing pharmacy are registered with DMS, the Denzapine Monitoring Service.

Tablets

Available as 25mg, 50mg, 100mg and 200mg strengths, are scored and licensed to be split in half. They can be crushed and mixed with water or soft food; this is off-label use. The tablets are uncoated but the drug is insoluble; be careful to ensure the whole dose is taken.

Oral suspension

A licensed preparation (50mg/ml) that can be mixed with water if necessary. Avoid mixing with acidic liquids such as orange juice. It does not require fridge storage and has an expiry of 90 days after opening. Store the bottle in the outer carton to protect from light. Shake the bottle vigorously for 10 seconds before each use. as clozapine particles may settle.

Zaponex

Available as tablets and orodispersible tablets.

Can only be used if the patient, prescriber and dispensing pharmacy are registered with ZTAS, the Zaponex Treatment Access System.

Tablets

Available as 25mg, 50mg, 100mg and 200mg strengths, are scored and licensed to be split in half. They can be crushed and mixed with water or soft food; this is off-label use. The tablets are uncoated but the drug is insoluble; be careful to ensure the whole dose is taken.

Orodispersible tablets

Available as 12.5mg, 25mg, 50mg, 100mg and 200mg strengths, licensed for oral administration. They should be placed on the tongue and will rapidly disintegrate in saliva to be swallowed. Orodispersible tablets may not be suitable for people unable to control their swallow. The tablets can be dispersed in water; this is ‘off-label’.

Switching preparations

In all cases of switching, liaise with the person’s specialist mental health team. Counsel the person or carer about the changes made, and ensure they can take or administer the preparation safely.

Reduced blood levels of clozapine have been seen in some people switched from whole tablets to crushed tablets or suspension, but data are sparse. Be careful to ensure the whole dose of crushed tablet is taken and that suspensions are shaken before use.

Monitor the person for response and tolerability if the brand, formulation or method of administration is changed. Ask the person or carer to report any changes in mental or physical health.

There have been reports of relapse when people stabilised on one brand of clozapine have switched to another. However, in most cases, switching appears to be safe and uneventful.

Following a switch, it may be useful to monitor clozapine blood levels if a baseline level is available. Seek advice from the person’s specialist mental health team who will arrange testing if necessary.

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