Inclusion Criteria:

- Male or female

- Aged > 18 years

- Suffering from a newly diagnosed squamous cell carcinoma of the oral cavity,
oropharynx, hypopharynx or larynx histologically-confirmed and having undergone
resective surgery

- Prior neoadjuvant chemotherapy allowed provided that, the patient did not experience
a WHO grade > 2 oral mucositis during the neoadjuvant therapy.

- Patient eligible to receive concurrent chemo-radiation defined as:

1. A continuous course of conventional external beam irradiation (IMRT eligible)
with a minimum cumulative radiation dose of 50 Gy or a maximum of 70 Gy, based
on a daily dosing between 1.8 and 2.2 Gy combined with platinum based
chemotherapy on a weekly or tri-weekly cycles.

2. Planned radiation treatment fields must include at least two oral tissue sites
(among right or left buccal mucosa, floor of mouth, tongue, right or left soft
palate) with each site receiving a total of 50 Gy or a maximum of 70 Gy. The
radiation treatment plan will be reviewed by a designated radiation oncologist.

- ECOG performance status ≤2

- Screening laboratory tests:

1. Haemoglobin ≥ 10g/dL

2. Absolute neutrophil counts ≥ 1500 cells/mm3

3. Platelets ≥ 100.000/mm3

4. Conjugated bilirubin ≤ 2 times Upper Limit of Normal (ULN)

5. Serum AST and ALT ≤ 3 ULN

6. Negative serum pregnancy test

- Women of child bearing potential must have effective contraception method (oral or
device)

- Signed written informed consent

Exclusion Criteria:

- Tumours of the lips, sinuses, salivary glands

- Prior radiation of the head and neck area

- Curative surgery less than 2 weeks or more than 15 weeks prior to the initiation of
RT-CT

- Presence of active infectious disease

- Presence of active oral infectious disease, including oropharyngeal candidiasis
and/or orofacial herpes

- Presence of oral mucositis

- Known or suspected chronic viral diseases including HIV

- Systolic blood pressure < 100 mmHg and/or Diastolic blood pressure < 50 mmHg

- Recent stroke within the last 6 months

- Bradyarrhythmia (<60 b/min), including sinus node dysfunction or AV nodal conduction
block 2nd or 3rd degree

- Subjects with orthostatic hypotension, defined by a decrease of systolic BP and/or
diastolic BP above 20 mmHg when the patient stands up

- Renal insufficiency (creatinine blood level > 1.5ULN)

- Ongoing heavy alcohol consumption (>100g alcohol/day)

- Administration of any concomitant treatment likely to interfere with clonidine

- Known hypersensitivity to clonidine, history of allergy or intolerance to milk
proteins or any other component of the product

- Presence of severe or uncontrolled depression

- Pregnant or breast-feeding women

- Inability to give informed consent or comply with study requirements

- Unable or unwilling to comply with follow-up visits

- Participation to a clinical trial within 30 days prior to randomization and during
the entire duration of the study