Ruling 1110
Whenever one says or hears the blessed name of His Eminence, the Messenger of Allah (Ṣ) – such as ‘Muḥammad’ and ‘Aḥmad’ – or an epithet (laqab) or kunyah[1] of his – such as ‘Muṣṭafā’ and ‘Abū al-Qāsim’ – even during prayers, it is recommended that he recite ṣalawāt.
-Ayatullah Sistani, Practical Laws of Islam, Prayer (Salah)
1
This is an appellation given to someone as the father or mother of someone.